Automation

Valve Automation Reference & FAQ

Everything You Need to Know About
Valve Automation Accessories

The definitive technical guide to valve positioners, limit switch boxes, air filter regulators, solenoid valves, air volume boosters, and hazardous area certifications — from Archer Automation LLC, Houston, Texas.

Valve Positioners

Limit Switch Boxes

Air Filter Regulators

Solenoid Valves

Volume Boosters

ATEX / IECEx / UL

In Stock · Houston TX

Valve Automation — Fundamentals

What it is, how it works, and why it matters

Valve automation is the use of mechanical, pneumatic, or electrical devices to open, close, or precisely position a process valve without manual intervention. In oil and gas refineries, petrochemical plants, power stations, water treatment facilities, and manufacturing operations, hundreds or thousands of valves must be operated quickly, safely, and repeatably — often in locations that are hazardous, remote, or inaccessible to personnel.

An automated valve assembly typically consists of:

Automated valves reduce labor cost, eliminate exposure of workers to hazardous conditions, enable remote operation from a control room, support safety instrumented systems (SIS), and achieve positioning accuracy that no human operator can match continuously over years of service.

These represent fundamentally different applications and require different accessories:

CharacteristicOn/Off (Shutoff) ValveControl Valve
Position statesFully open or fully closedAny position 0–100%
Valve typesBall, butterfly, gate, plugGlobe, rotary, angle body
Actuator typeTypically rotary (90°) pneumaticLinear or rotary pneumatic
Key accessorySolenoid valve + limit switch boxValve positioner
Control signalOn/off (digital)4-20 mA or 3-15 psi (analog)
FeedbackOpen/closed confirmationContinuous position signal
Speed requirementFast stroking (ESD applications)Precise, stable positioning

An on/off valve uses a solenoid valve to direct air pressure to the actuator (open) or vent it (close/spring return), and a limit switch box to confirm the valve has reached its end-of-travel position. A control valve uses a positioner to continuously compare the commanded position to the actual position and correct any error, achieving precise throttling control.

The type of valve determines whether you need a rotary positioner (EPR, PPR) or linear positioner (EPL, PPL), and whether the actuator is single-acting (spring return) or double-acting (air-to-open and air-to-close).

pneumatic actuator converts compressed air pressure into mechanical force to move a valve. For rotary valves, this is typically done by a scotch-yoke or rack-and-pinion mechanism. For linear (globe) valves, a spring-opposed diaphragm or piston is used.

Single-Acting (Spring Return): Air pressure is applied to one side of the actuator to move the valve in one direction. A spring returns the valve to its “fail” position when air pressure is removed. This is the standard for safety-critical on/off valves — a power or air failure causes the valve to default to its safe position (fail-open or fail-closed). Requires only one air port connection on the positioner or solenoid valve.

Double-Acting: Air is used to move the valve in both directions — one port to open, another to close. No spring is present. Provides higher torque in both directions, used for large valves or where spring return is not practical. Requires two air connections (output A and output B) from the positioner. If air supply is lost, the valve stays in its last position.

Archer's ASD-5000 and ASD-7000 smart positioners use the same unit for both single-acting and double-acting applications — eliminating inventory complexity. The EPR and EPL also accommodate both configurations.

A complete automated valve assembly typically includes some or all of the following accessories, depending on application requirements:

AccessoryFunctionRequired For
Valve PositionerPositions valve precisely in response to 4-20 mA or 3-15 psi signalControl valves, throttling service
Air Filter RegulatorCleans and regulates instrument air supply pressureAll pneumatically operated valves
Solenoid ValveOn/off control of air to actuator; ESD de-energize-to-tripOn/off valves, safety trips
Limit Switch Box (VPM)Visual indication + electrical feedback of valve positionOn/off valves, confirmation of position
Air Volume BoosterIncreases air flow rate to large actuators to speed strokingLarge actuators, fast-stroking ESD valves
Mounting BracketNAMUR-standard or custom bracket to mount accessoriesAll accessories
Tubing & FittingsPneumatic interconnections between componentsAll pneumatic assemblies

 

Valve Positioners

PPR · PPL · EPR · EPL · ASD-5000 · ASD-7000

valve positioner is a closed-loop controller mounted directly on a pneumatic actuator. It continuously senses the actual valve position (through a mechanical feedback shaft or non-contact sensor), compares it to the desired position commanded by the control system, and adjusts the air pressure to the actuator until the two match.

 

Without a positioner, a control valve is subject to:

You need a positioner whenever precise, repeatable throttling is required. Common applications include flow control loops, pressure control, temperature control via heat exchangers, and any service where the valve must hold a specific intermediate position reliably.

Rule of thumb: If your control system sends a 4-20 mA or 3-15 psi signal to modulate a valve (not just open/close it), you need a positioner. If you only need open/closed operation, a solenoid valve and limit switch box are sufficient.

There are three main categories of pneumatic valve positioner:

TypeInput SignalArcher ModelsKey Feature
Pneumatic (P/P)3-15 psi pneumaticPPR, PPLIntrinsically Safe, no electronics
Electro-Pneumatic (I/P)4-20 mA DCEPR, EPL, EP-XPDirect 4-20 mA; diaphragm/torque motor
Smart (Digital)4-20 mA + HART/FF/ProfibusASD-5000, ASD-7000Auto-calibration, diagnostics, bus comms

 

Additionally, both pneumatic and electro-pneumatic positioners come in two feedback configurations:

The Archer PPR (rotary) and PPL (linear) are classic 3-15 psi force-balance positioners. They convert a pneumatic input signal directly into a proportional actuator output — entirely without electronic components. The instrument signal acts on an input capsule, deflecting a flapper relative to a nozzle; the resulting back-pressure shifts a pilot valve to route air to the actuator. A feedback spring connected to the actuator shaft opposes the input force, establishing balance at the commanded position.

Input Signal

3–15 psi pneumatic

Linearity (single)

±1.0% F.S.

Sensitivity

Within ±0.5% F.S.

Air Supply Max

7 bar (100 psi)

Temperature

-20°C to +70°C std.

Protection

Class 1, Div. 1, Type 4X

Choose PPR/PPL when:

The Archer EPR and EPL use a diaphragm valve and torque motor I/P conversion mechanism rather than the older relay/spool valve design used by many competitors. This is a critical distinction for real-world performance:

FeatureSpool/Relay Type (Competitors)Archer EPR/EPL (Diaphragm)
Dirt toleranceSpool valves foul with dirty air✔ Highly resistant — no spool valve
Air bleedHighest (continuous)— ~50% lower than relay type
Vibration resistanceRelay can resonate✔ Diaphragm/torque motor immune
Explosion-proofVaries✔ UL/cUL Cl. 1, Div.1, Grp C&D, T6
CalibrationSPAN/ZERO manual— Manual SPAN/ZERO (field simple)
Stainless gaugesOptional/extra cost✔ Standard included
Service lifeVaries✔ Proven 20+ year design life

 

Additional EPR/EPL features:

EPR — Rotary Cam Feedback

EPL — Linear Lever Feedback

EP-XP — Enhanced Explosion-Proof

smart positioner adds a microprocessor between the 4-20 mA control signal and the pneumatic output. Instead of mechanical SPAN and ZERO screws, the positioner runs an automatic calibration routine that maps the full actuator stroke in seconds. Additional capabilities include digital communication, valve diagnostics, and data logging.

The Archer ASD-5000 and ASD-7000 use a diaphragm valve and torque motor I/P mechanism — the same proven technology as the EPR/EPL — but under microprocessor control. This gives the Archer ASD series a critical advantage over competing smart positioners that use piezo valves:

FeaturePiezo-Valve Smart Positioners (Others)Archer ASD-5000/7000
Air filtration required✗ Must filter to 40 micron — fouling causes failure✔ 5 micron standard — much more tolerant
Vibration tolerance✗ Sensitive — hunting in rough service✔ High — torque motor design
Single/double acting✗ Different valve block required✔ Same unit for both configurations
Calibration✔ One-touch auto✔ One-touch auto
HART communication✔ Yes✔ 7th generation HART
Foundation FieldbusSome models✔ ASD-7000 option
ATEX FlameproofSome models✔ ASD-7000 (Ex d IIB T6)
Position sensorVaries✔ Non-contact hall-effect (no wear)
Air bleed✔ Zero bleed (piezo)— Low bleed (not zero)

 

ASD-5000 key features: 4-20 mA with HART 7, ATEX/IECEx Intrinsically Safe, one-touch auto-calibration, partial stroke testing (PST), valve signature diagnostics, LCD display with push-button programming, stainless steel enclosure option.

ASD-7000 additional features: ATEX/IECEx Flameproof (Ex d IIB T6) for Zone 1 hazardous areas, HART / Foundation Fieldbus / Profibus options, SIL-capable, operating range -40°C to +85°C.

Split-range control uses a single 4-20 mA output from a controller to operate two or more valves, each responding to a different portion of the control signal range. This allows a single PID loop to control two actuators in sequence.

 

Common split-range configurations:

Archer EPR, EPL, PPR, and PPL positioners all support ½ split range as a standard feature. Each positioner is configured with its own SPAN and ZERO settings to respond to its assigned portion of the signal range.

Split-range positioners use the same hardware — only the calibration adjustments differ. No special split-range model is required for Archer positioners.

Follow this decision sequence:

  1. Identify your control signal: 3-15 psi → PPR/PPL pneumatic. 4-20 mA → EPR/EPL or ASD series.
  2. Identify your valve/actuator type: Quarter-turn rotary (ball, butterfly) → R suffix (EPR, PPR, ASD-5000/7000 rotary). Sliding stem/linear (globe, gate) → L suffix (EPL, PPL).
  3. Identify your actuator action: Single-acting (spring return) or double-acting. All Archer positioners support both; ASD series uses same unit for either.
  4. Assess your environment: Dirty air, high vibration? → EPR/EPL or ASD (diaphragm/torque motor). Must be IS with no barriers? → PPR/PPL. Division 1 Flameproof + HART? → ASD-7000.
  5. Identify diagnostic needs: Need HART, PST, valve diagnostics? → ASD-5000 or ASD-7000. Simple throttling with proven reliability? → EPR/EPL.
  6. Temperature range: Standard service → standard models. High temp (+120°C) or low temp (-40°C) → check options table or contact Archer.

Not sure? Contact Archer Automation at (713) 817-3337 or sales@archer-automation.com — we provide no-cost application sizing support.

Valve Positioners

PPR · PPL · EPR · EPL · ASD-5000 · ASD-7000

valve positioner is a closed-loop controller mounted directly on a pneumatic actuator. It continuously senses the actual valve position (through a mechanical feedback shaft or non-contact sensor), compares it to the desired position commanded by the control system, and adjusts the air pressure to the actuator until the two match.

 

Without a positioner, a control valve is subject to:

You need a positioner whenever precise, repeatable throttling is required. Common applications include flow control loops, pressure control, temperature control via heat exchangers, and any service where the valve must hold a specific intermediate position reliably.

Rule of thumb: If your control system sends a 4-20 mA or 3-15 psi signal to modulate a valve (not just open/close it), you need a positioner. If you only need open/closed operation, a solenoid valve and limit switch box are sufficient.

There are three main categories of pneumatic valve positioner:

TypeInput SignalArcher ModelsKey Feature
Pneumatic (P/P)3-15 psi pneumaticPPR, PPLIntrinsically Safe, no electronics
Electro-Pneumatic (I/P)4-20 mA DCEPR, EPL, EP-XPDirect 4-20 mA; diaphragm/torque motor
Smart (Digital)4-20 mA + HART/FF/ProfibusASD-5000, ASD-7000Auto-calibration, diagnostics, bus comms

 

Additionally, both pneumatic and electro-pneumatic positioners come in two feedback configurations:

The Archer PPR (rotary) and PPL (linear) are classic 3-15 psi force-balance positioners. They convert a pneumatic input signal directly into a proportional actuator output — entirely without electronic components. The instrument signal acts on an input capsule, deflecting a flapper relative to a nozzle; the resulting back-pressure shifts a pilot valve to route air to the actuator. A feedback spring connected to the actuator shaft opposes the input force, establishing balance at the commanded position.

Input Signal

3–15 psi pneumatic

Linearity (single)

±1.0% F.S.

Sensitivity

Within ±0.5% F.S.

Air Supply Max

7 bar (100 psi)

Temperature

-20°C to +70°C std.

Protection

Class 1, Div. 1, Type 4X

Choose PPR/PPL when:

The Archer EPR and EPL use a diaphragm valve and torque motor I/P conversion mechanism rather than the older relay/spool valve design used by many competitors. This is a critical distinction for real-world performance:

FeatureSpool/Relay Type (Competitors)Archer EPR/EPL (Diaphragm)
Dirt toleranceSpool valves foul with dirty air✔ Highly resistant — no spool valve
Air bleedHighest (continuous)— ~50% lower than relay type
Vibration resistanceRelay can resonate✔ Diaphragm/torque motor immune
Explosion-proofVaries✔ UL/cUL Cl. 1, Div.1, Grp C&D, T6
CalibrationSPAN/ZERO manual— Manual SPAN/ZERO (field simple)
Stainless gaugesOptional/extra cost✔ Standard included
Service lifeVaries✔ Proven 20+ year design life

 

Additional EPR/EPL features:

EPR — Rotary Cam Feedback

EPL — Linear Lever Feedback

EP-XP — Enhanced Explosion-Proof

smart positioner adds a microprocessor between the 4-20 mA control signal and the pneumatic output. Instead of mechanical SPAN and ZERO screws, the positioner runs an automatic calibration routine that maps the full actuator stroke in seconds. Additional capabilities include digital communication, valve diagnostics, and data logging.

The Archer ASD-5000 and ASD-7000 use a diaphragm valve and torque motor I/P mechanism — the same proven technology as the EPR/EPL — but under microprocessor control. This gives the Archer ASD series a critical advantage over competing smart positioners that use piezo valves:

FeaturePiezo-Valve Smart Positioners (Others)Archer ASD-5000/7000
Air filtration required✗ Must filter to 40 micron — fouling causes failure✔ 5 micron standard — much more tolerant
Vibration tolerance✗ Sensitive — hunting in rough service✔ High — torque motor design
Single/double acting✗ Different valve block required✔ Same unit for both configurations
Calibration✔ One-touch auto✔ One-touch auto
HART communication✔ Yes✔ 7th generation HART
Foundation FieldbusSome models✔ ASD-7000 option
ATEX FlameproofSome models✔ ASD-7000 (Ex d IIB T6)
Position sensorVaries✔ Non-contact hall-effect (no wear)
Air bleed✔ Zero bleed (piezo)— Low bleed (not zero)

 

ASD-5000 key features: 4-20 mA with HART 7, ATEX/IECEx Intrinsically Safe, one-touch auto-calibration, partial stroke testing (PST), valve signature diagnostics, LCD display with push-button programming, stainless steel enclosure option.

ASD-7000 additional features: ATEX/IECEx Flameproof (Ex d IIB T6) for Zone 1 hazardous areas, HART / Foundation Fieldbus / Profibus options, SIL-capable, operating range -40°C to +85°C.

Split-range control uses a single 4-20 mA output from a controller to operate two or more valves, each responding to a different portion of the control signal range. This allows a single PID loop to control two actuators in sequence.

 

Common split-range configurations:

Archer EPR, EPL, PPR, and PPL positioners all support ½ split range as a standard feature. Each positioner is configured with its own SPAN and ZERO settings to respond to its assigned portion of the signal range.

Split-range positioners use the same hardware — only the calibration adjustments differ. No special split-range model is required for Archer positioners.

Follow this decision sequence:

  1. Identify your control signal: 3-15 psi → PPR/PPL pneumatic. 4-20 mA → EPR/EPL or ASD series.
  2. Identify your valve/actuator type: Quarter-turn rotary (ball, butterfly) → R suffix (EPR, PPR, ASD-5000/7000 rotary). Sliding stem/linear (globe, gate) → L suffix (EPL, PPL).
  3. Identify your actuator action: Single-acting (spring return) or double-acting. All Archer positioners support both; ASD series uses same unit for either.
  4. Assess your environment: Dirty air, high vibration? → EPR/EPL or ASD (diaphragm/torque motor). Must be IS with no barriers? → PPR/PPL. Division 1 Flameproof + HART? → ASD-7000.
  5. Identify diagnostic needs: Need HART, PST, valve diagnostics? → ASD-5000 or ASD-7000. Simple throttling with proven reliability? → EPR/EPL.
  6. Temperature range: Standard service → standard models. High temp (+120°C) or low temp (-40°C) → check options table or contact Archer.

Not sure? Contact Archer Automation at (713) 817-3337 or sales@archer-automation.com — we provide no-cost application sizing support.

Air Filter Regulators

FR-10 · FR-20 · FR-30 Series

Compressed air in industrial plants is never perfectly clean. Even with upstream dryers and filters, instrument air supply lines accumulate:

Any of these contaminants will damage or impair the performance of positioners, solenoid valves, and other precision instruments. The air filter regulator provides two essential functions at the point of use:

  1. Filtration: Removes particulates, water, and oil droplets down to 5 microns before they reach sensitive instrument internals
  2. Pressure regulation: Maintains a constant, stable output pressure to the instrument regardless of fluctuations in the upstream supply line — critical for positioner accuracy and solenoid valve reliability

Smart positioners using piezo valves require air filtered to 40 microns or finer. Archer EPR/EPL and ASD positioners are designed to tolerate dirtier air, but an air filter regulator is still required on every instrument to maintain accuracy and protect against pressure surges.

The Archer FR Series air filter regulators are designed to provide clean, dry, regulated instrument air to valve positioners, solenoid valves, and pneumatic actuators. All models feature 5-micron filter elements, stainless steel pressure gauges as standard, self-relief function to balance output and setting pressures, and availability in aluminum die-cast or stainless steel 316 housing.

ModelPort SizeOutput PressureMax SupplyTemp. RangeDrain Type
FR-10NPT 1/4 or PT(Rc) 1/40-4 bar (60 psi) or 0-8 bar (120 psi)15 bar (225 psi)-20°C to +70°CFixed (manual)
FR-20NPT 1/4 or PT(Rc) 1/40-4 bar or 0-8 bar15 bar (225 psi)-20°C to +70°C or -40°C to +80°CManual or Auto (float)
FR-30NPT 1/2, NPT 3/4, PT(Rc) 1/2 or 3/40-4 bar or 0-8 bar15 bar (225 psi)-20°C to +70°C or -40°C to +80°CManual or Auto (float)

FR-10: The compact standard unit for positioners and solenoid valves in most applications. Rugged aluminum die-cast or optional stainless steel 316 housing. Stable setting pressure with high-capacity 5-micron filter. Self-relief function prevents over-pressurization. Weight: 0.5 kg aluminum / 1 kg SS.

FR-20: Adds exceptional sensitivity and precision setting, outstanding stability and repeatability, and optional auto-drain (float type) for wet environments or unattended service. Available in extended temperature range (-40°C to +80°C) for outdoor arctic or process areas. Weight: 0.65 kg / 1.4 kg.

FR-30: High-flow unit for larger actuators, volume boosters, or multiple instruments sharing a single supply point. ½” and ¾” NPT ports handle larger air volumes without excessive pressure drop. Weight: 1.6 kg / 3.4 kg.

FR10-R1 / FR10-N1 (Aluminum)

FR11-R1 / FR11-N1 (SS316)

FR30 — 1/2″ and 3/4″ NPT

The correct supply pressure setting depends on your actuator and valve requirements. General guidelines:

All Archer FR series regulators include a stainless steel pressure gauge as standard — always install with the gauge visible for verification during commissioning and maintenance checks.

Aluminum die-cast housing (standard): Suitable for most industrial environments including outdoor installation. Lower cost and lighter weight. Appropriate where the atmosphere does not contain significant concentrations of chlorides, sulfides, or other aggressive corrosives.

 

Stainless Steel 316 housing: Required in:

Stainless steel FR units are approximately 2x the weight and cost of aluminum equivalents but provide significantly extended service life in aggressive environments. Archer offers SS316 versions of all FR-10, FR-20, and FR-30 models.

Solenoid Valves for Valve Automation

On/off control · NAMUR mount · Single & double acting

solenoid valve is an electromechanically operated directional control valve that uses an electromagnetic coil (solenoid) to move an internal plunger or spool, which in turn opens or closes pneumatic ports to direct air flow. When the coil is energized, the magnetic field lifts the plunger against a spring, opening the valve. When de-energized, the spring returns the plunger to its original position.

 

In valve automation, solenoid valves serve several critical roles:

Solenoid valves are classified by the number of ports (“ways”) and positions:

3/2-way (3-port, 2-position): Three ports — supply (P), work/actuator (A), and exhaust (R). Two positions — open and closed. This is the standard configuration for single-acting (spring-return) pneumatic actuators. When energized: P→A (air to actuator, valve opens). When de-energized: A→R (actuator vents, spring closes valve). Available normally closed (NC) or normally open (NO).

5/2-way (5-port, 2-position): Five ports — supply (P), two work ports (A and B), and two exhaust ports (R1 and R2). Two positions. Standard for double-acting pneumatic actuators. When energized: P→A (opens), B→R. When de-energized: P→B (closes), A→R. Provides air-to-open and air-to-close, with no spring return.

5/3-way (5-port, 3-position): Adds a center position where all ports are either blocked (closed center — valve stays in position), vented (exhaust center — actuator loses air), or pressurized. Used for fail-in-place applications on double-acting actuators.

2/2-way: Simple on/off shutoff — one inlet, one outlet. Used as a block valve on the instrument air supply rather than directly on the actuator.

Smart positioners using piezo valves require air filtered to 40 microns or finer. Archer EPR/EPL and ASD positioners are designed to tolerate dirtier air, but an air filter regulator is still required on every instrument to maintain accuracy and protect against pressure surges.

NAMUR mounting (per VDI/VDE 3845) allows a solenoid valve to be bolted directly onto the face of a rotary pneumatic actuator using a standardized bolt pattern and O-ring sealing — eliminating all external pneumatic tubing between the solenoid and actuator. Two O-rings seal the supply and work ports directly at the interface.

Advantages of NAMUR mounting:

NAMUR solenoid valves use G1/4″ or G1/2″ port sizing. US actuators may use #10-24 thread patterns. In-line solenoid valves with threaded NPT ports (1/4″, 3/8″, 1/2″) are used where NAMUR mounting is not available or the solenoid must be located remotely from the actuator.

“De-energize to trip” (also called “normally energized” or “energize to hold”) means the solenoid valve is continuously energized during normal operation to hold the process valve open. When a safety system trips — due to a process alarm, power failure, instrument air failure, or control system fault — the solenoid coil de-energizes, air is vented from the actuator, and the spring forces the valve to its safe position (typically closed).

 

This is the preferred configuration for ESD valves because:

Never use "energize to trip" (NC solenoid, energize to close) for ESD valves unless specifically required by process safety analysis. A failed solenoid coil in an "energize to trip" design will not provide the ESD function when needed.

Industrial solenoid valves for valve automation are available in these standard voltages:

For hazardous area solenoid valves (Explosion-Proof or IS certified), 24 VDC is the overwhelming preference because:

The LSB-7000 integrated solenoid valve (built into the limit switch box) simplifies the wiring by combining the solenoid and limit switches in one cable entry — critical in hazardous areas where minimizing penetrations reduces risk and installation cost.

Solenoid Valves for Valve Automation

On/off control · NAMUR mount · Single & double acting

solenoid valve is an electromechanically operated directional control valve that uses an electromagnetic coil (solenoid) to move an internal plunger or spool, which in turn opens or closes pneumatic ports to direct air flow. When the coil is energized, the magnetic field lifts the plunger against a spring, opening the valve. When de-energized, the spring returns the plunger to its original position.

 

In valve automation, solenoid valves serve several critical roles:

Solenoid valves are classified by the number of ports (“ways”) and positions:

3/2-way (3-port, 2-position): Three ports — supply (P), work/actuator (A), and exhaust (R). Two positions — open and closed. This is the standard configuration for single-acting (spring-return) pneumatic actuators. When energized: P→A (air to actuator, valve opens). When de-energized: A→R (actuator vents, spring closes valve). Available normally closed (NC) or normally open (NO).

5/2-way (5-port, 2-position): Five ports — supply (P), two work ports (A and B), and two exhaust ports (R1 and R2). Two positions. Standard for double-acting pneumatic actuators. When energized: P→A (opens), B→R. When de-energized: P→B (closes), A→R. Provides air-to-open and air-to-close, with no spring return.

5/3-way (5-port, 3-position): Adds a center position where all ports are either blocked (closed center — valve stays in position), vented (exhaust center — actuator loses air), or pressurized. Used for fail-in-place applications on double-acting actuators.

2/2-way: Simple on/off shutoff — one inlet, one outlet. Used as a block valve on the instrument air supply rather than directly on the actuator.

Smart positioners using piezo valves require air filtered to 40 microns or finer. Archer EPR/EPL and ASD positioners are designed to tolerate dirtier air, but an air filter regulator is still required on every instrument to maintain accuracy and protect against pressure surges.

NAMUR mounting (per VDI/VDE 3845) allows a solenoid valve to be bolted directly onto the face of a rotary pneumatic actuator using a standardized bolt pattern and O-ring sealing — eliminating all external pneumatic tubing between the solenoid and actuator. Two O-rings seal the supply and work ports directly at the interface.

Advantages of NAMUR mounting:

NAMUR solenoid valves use G1/4″ or G1/2″ port sizing. US actuators may use #10-24 thread patterns. In-line solenoid valves with threaded NPT ports (1/4″, 3/8″, 1/2″) are used where NAMUR mounting is not available or the solenoid must be located remotely from the actuator.

“De-energize to trip” (also called “normally energized” or “energize to hold”) means the solenoid valve is continuously energized during normal operation to hold the process valve open. When a safety system trips — due to a process alarm, power failure, instrument air failure, or control system fault — the solenoid coil de-energizes, air is vented from the actuator, and the spring forces the valve to its safe position (typically closed).

 

This is the preferred configuration for ESD valves because:

Never use "energize to trip" (NC solenoid, energize to close) for ESD valves unless specifically required by process safety analysis. A failed solenoid coil in an "energize to trip" design will not provide the ESD function when needed.

Industrial solenoid valves for valve automation are available in these standard voltages:

For hazardous area solenoid valves (Explosion-Proof or IS certified), 24 VDC is the overwhelming preference because:

The LSB-7000 integrated solenoid valve (built into the limit switch box) simplifies the wiring by combining the solenoid and limit switches in one cable entry — critical in hazardous areas where minimizing penetrations reduces risk and installation cost.

Hazardous Area Approvals — Complete Guide

ATEX · IECEx · UL/NEC · CSA · SIL · Gas Groups · Temperature Classes

hazardous area (also called a “hazardous location” in North America or an “explosive atmosphere” in IEC/ATEX terminology) is any location where flammable gases, vapors, mists, or combustible dusts may be present in concentrations sufficient to form an ignitable or explosive mixture with air.

Industries with hazardous areas include:

Any electrical equipment installed in a hazardous area must be certified to prevent it from becoming a source of ignition — through arcing contacts, hot surfaces, or electrostatic discharge. Without certification, using standard electrical equipment in a hazardous area creates the risk of an explosion or fire. Certification is a legal requirement in all jurisdictions.

 

Valve automation accessories — limit switch boxes, smart positioners, electro-pneumatic positioners, and solenoid valves — all contain electrical components and require hazardous area certification for use in explosive atmospheres.

Both ATEX and IECEx are based on the same underlying technical standards (IEC 60079 series) and classify equipment for use in explosive atmospheres, but they differ in legal basis, geography, and certification process:

AspectATEXIECEx
Full nameATmosphères EXplosiblesIEC System for Certification to Standards for Explosive Atmospheres
Legal basisEU Directive 2014/34/EU (mandatory in EU)International voluntary scheme (not legally binding)
GeographyEuropean Union + EEA countriesGlobal — accepted in 50+ countries
Self-certificationPermitted for Category 3 (Zone 2) equipmentNot permitted — always independent assessment
Certification rigorNotified Body required for Cat. 1 & 2ExCB (testing) + QAR (factory audit) always required
Certificate verificationEU Declaration of ConformityIECEx Certificate publicly searchable online at iecex.com
Applies toBoth electrical and non-electrical equipmentElectrical equipment only

Products with both ATEX and IECEx certification can be deployed on global projects — in European refineries, Asian petrochemical plants, Middle Eastern LNG facilities, and Australian offshore platforms — without re-certification. Archer’s LSB-3000 and ASD-7000 carry both certifications for this reason.

Hazardous areas are classified by the likelihood and duration of an explosive atmosphere being present:

IEC / ATEX Zone System (Gas):

Zone 0
Continuous

Explosive gas present continuously or for long periods during normal operations

Zone 1
Likely

Explosive gas likely to occur in normal operation

Zone 2
Unlikely

Explosive gas not likely in normal operation; may occur briefly

IEC / ATEX Zone System (Dust):

Zone 20
Continuous

Combustible dust present continuously or for long periods

Zone 21
Likely

Combustible dust cloud likely in normal operation

Zone 22
Unlikely

Combustible dust cloud not likely; present only briefly

North American Class/Division System (NEC/CEC):

NECDescriptionIEC Equivalent
Class I, Division 1Flammable gas present under normal conditions OR if equipment failsZone 0 + Zone 1
Class I, Division 2Flammable gas present only under abnormal conditions (equipment failure)Zone 2
Class II, Division 1Combustible dust present under normal conditionsZone 20 + Zone 21
Class II, Division 2Combustible dust present only under abnormal conditionsZone 22
Class IIIIgnitable fibers (e.g., textile mills) — no IEC equivalent

Equipment rated for Zone 1 is acceptable in Zone 2 (higher safety level covers lower hazard). Similarly, Division 1 rated equipment is acceptable for Division 2 areas. The Archer LSB-3000 and ASD-7000 are rated for Zone 1 / Division 1 — the most stringent hazardous area classification for process industries.

Gas Groups classify flammable gases and vapors by their energy required for ignition and their explosion characteristics. Equipment must be certified for the gas group(s) present in the hazardous area.

IEC / ATEX Gas Groups (Equipment Group II — surface industries):

GroupRepresentative GasRisk LevelNotes
IICHydrogen, acetyleneHighestIIC covers all gases — select IIC equipment for any gas group
IIBEthylene, cyclopropaneHighIIB covers IIB and IIA gases
IIAPropane, methane, natural gasModerateMost common in oil and gas

North American Gas Groups (NEC/CEC):

GroupRepresentative GasIEC Equivalent
Group AAcetyleneIIC
Group BHydrogenIIC
Group CEthylene, cyclopropaneIIB
Group DPropane, methane, natural gas, gasolineIIA

Most oil and gas applications involve Group D (NEC) or Group IIA/IIB (IEC) gases. The Archer EPR/EPL is UL-certified for Class I, Division 1, Groups C and D, T6. The LSB-3000 and ASD-7000 are certified for IIC — the most stringent gas group, covering all hazardous gas applications globally.

These are different protection concepts (methods of preventing ignition), each appropriate for different applications:

Explosion-Proof / Flameproof (Ex d): The enclosure is designed and tested to contain any internal explosion — preventing it from propagating to the surrounding atmosphere through specially designed flame paths (flanged joints). Used in Division 1 (US) / Zone 1 (IEC). The Archer LSB-3000 and ASD-7000 use this method. Note: the enclosure is not “explosion-proof” in the sense of preventing an internal explosion, but rather in preventing it from causing an external explosion.

 

Intrinsically Safe (Ex ia / Ex ib): Limits the electrical energy in the circuit to levels too low to ignite the hazardous atmosphere, even under fault conditions. The device itself consumes very little energy — requires IS barriers (Zener or galvanic isolator) in the safe area. Used for sensors, transmitters, and solenoid valves with very low power consumption. Ex ia is suitable for Zone 0 (the most demanding); Ex ib for Zone 1. Archer PPR/PPL pneumatic positioners are IS by virtue of containing no electrical components. ASD-5000 is ATEX/IECEx Ex ia certified.

 

Increased Safety (Ex e): Additional measures prevent sparks and excessive temperatures in equipment that doesn’t normally produce arcs — terminal boxes, motors, lighting fixtures. Not appropriate for switching devices.

 

Non-sparking / Non-incendive (Ex n / Ex nA): Equipment designed not to produce sparks under normal operating conditions. Used in Zone 2 / Division 2 only. Simpler and lower cost than Flameproof or IS — suitable for equipment unlikely to fault.

Purge and Pressurization (Ex p): Enclosure is continuously purged with clean air or inert gas, preventing entry of hazardous atmosphere. Used for large control panels and analyzer enclosures in Zone 1/Division 1.

MethodCodeZoneBest ForArcher Example
FlameproofEx dZone 1 (1&2)Switch boxes, positioners, solenoidsLSB-3000, ASD-7000
Intrinsically SafeEx iaZone 0,1,2Sensors, transmitters, IS solenoidsASD-5000, PPR/PPL
Intrinsically SafeEx ibZone 1,2Sensors, solenoidsLSB switches (P&F)
Non-sparkingEx n/nAZone 2 onlyLow-risk equipment, terminal boxesLSB-1000 (Div. 2)
General PurposeIP6xNon-hazardousWeatherproof locationsLSB-1000, FR series

A complete ATEX/IECEx marking follows this structure. Example from the Archer LSB-3000:

ⓔ II 2 G Ex d IIC T6 Gb / II 2 D Ex tb IIIC T85°C Db

Marking ElementValue (Example)Meaning
CE mark + Notified Body No.⓬ (ATEX only)EU certification; Notified Body number
Ex symbolⓔ or ⟨Ex⟩Explosion protection present
Equipment GroupIIII = surface industries (not mines)
Equipment Category21=Zone 0; 2=Zone 1; 3=Zone 2
Type of AtmosphereGG = gas/vapor/mist; D = dust
Protection TypeEx dd = Flameproof; ia = IS (Zone 0); ib = IS (Zone 1)
Gas GroupIICIIC = Hydrogen/Acetylene (covers all gases)
Temperature ClassT6Max surface 85°C — most stringent class
Equipment Protection LevelGbEPL Gb = very high protection for gas, Zone 1

North American UL/cUL marking example (Archer EPR/EPL):

cULus Listed — Class I, Division 1, Groups C and D, T6 — Type 4X

This means: UL certified for US and Canada (cULus) — Flammable gas present in normal operation (Division 1) — Ethylene/Propane/Natural gas environments (Groups C&D) — Max surface temperature 85°C (T6) — Weatherproof, corrosion-resistant enclosure (Type 4X).

Always verify the complete certification string — not just "ATEX certified." A product certified Ex n (Zone 2 only) is not suitable for Zone 1 installation, regardless of how it's marketed.

Archer Automation products carry the following hazardous area certifications:

ProductUL/cUL (North America)ATEX (Europe)IECEx (International)Other
EPR / EPL PositionerClass I, Div. 1, Grp C&D, T6, Type 4XCE
PPR / PPL PositionerClass I, Div. 1, Type 4X (IS by design)CE
ASD-5000Ex ia IIC T6 Ga/GbEx ia IIC T6CE, SIL 2
ASD-7000Ex d IIB T6 Gb / Ex ia IIC T6 GaEx d IIB T6 / Ex ia IIC T6CE, HART/FF/Profibus, SIL 2
LSB-1000Type 4, 4x, IP66/67Ex ia IIC (switches)CE
LSB-3000Type 4, 4xEx d IIC T6 / Ex ia IICEx d IIC T6 / Ex ia IICCE, EAC, KCs
LSB-7000Ex d IIC T6 (with solenoid)Ex d IIC T6CE, EAC
FR Series (filter regulators)CE marked⟨Ex⟩ (non-electrical)CE

SIL 3 Capable

IECEx

ATEX

UL / cUL

The IP (Ingress Protection) rating per IEC 60529 defines an enclosure’s protection against solids and liquids. The two-digit code indicates: first digit = solid protection (0-6); second digit = liquid protection (0-9K).

IP RatingSolid ProtectionLiquid ProtectionApplication
IP65Dust-tight (no ingress)Protected against water jets from any directionIndoor/outdoor; not suitable for washdown
IP66Dust-tightProtected against powerful water jets (heavy seas)Outdoor; heavy rain; high-pressure washdown
IP67Dust-tightProtected against temporary immersion (1 m, 30 min)Areas subject to flooding; valve pits
IP68Dust-tightProtected against continuous immersion (depth and time per manufacturer)Subsea / permanent immersion applications

The Archer LSB-1000 is rated IP66 and IP67 standard, with optional IP68 for submersible applications. LSB-3000 (Flameproof) is also rated IP67.

NEMA Types (North American equivalent):

Most Archer limit switch boxes and positioners carry both NEMA Type 4X and IP66/67 ratings, satisfying both North American and international specifications simultaneously.

SIL (Safety Integrity Level) is a measure of risk reduction provided by a Safety Instrumented Function (SIF) — a combination of sensors, logic solvers, and final elements (valves) that take a process to a safe state when a hazardous condition is detected. SIL levels are defined in IEC 61508 (functional safety standard) and applied to process industries through IEC 61511.

SIL LevelProbability of Failure on Demand (PFD)Risk Reduction Factor
SIL 10.1 to 0.01 (10% to 1%)10 to 100
SIL 20.01 to 0.001 (1% to 0.1%)100 to 1,000
SIL 30.001 to 0.0001 (0.1% to 0.01%)1,000 to 10,000
SIL 4< 0.0001> 10,000

For valve automation, the final element (valve + actuator + solenoid valve + positioner) is a critical part of the SIL calculation. Key concepts:

The Archer ASD-7000 carries SIL 2 certification (IEC 61508) as a single device. SIL 3 is achievable in redundant configurations. Contact Archer for FMEDA data sheets for SIL calculations on your specific application.

An Intrinsically Safe (IS) barrier is a device installed in the safe area (control room or marshaling cabinet) that limits the voltage, current, and energy that can be delivered to IS-rated field instruments in the hazardous area. If a fault occurs — a short circuit, insulation failure, or power supply overvoltage — the barrier prevents energy exceeding the safe limit from reaching the field instrument.

Two barrier types are used:

IS barriers are required when:

When using Archer LSB limit switch boxes with hermetically sealed TTL (non-contact reed) switches in Division 2 / Zone 2 — barriers are NOT required. TTL switches are hermetically sealed and can be used in Division 2 Groups A, B, C & D without conduit seal fittings.

Lock-Out Valves

Pneumatic instrument air isolation for safe maintenance

A lock-out valve (also called a pneumatic lockout/tagout valve, supply isolation valve, or instrument air isolation valve) is a manually operated valve installed in the instrument air supply line to an automated valve assembly. It provides a positive, lockable isolation point that allows maintenance personnel to safely isolate the pneumatic supply — and lock it in the isolated (off) position — before working on the positioner, solenoid valve, limit switch box, or actuator. Why lock-out valves are required:

A standard ¼-turn ball valve or needle valve is not LOTO-compliant unless it has a lockable handle that can accept a padlock. Always specify a lockable lock-out valve for instrument air isolation on all automated valve assemblies.

Archer Automation offers lock-out valves designed specifically for instrument air supply isolation in valve automation applications. These are lockable quarter-turn ball valves with handles that accept a standard padlock through the handle flange — preventing re-opening while the maintenance lock is applied.

Key features of Archer lock-out valves:

Lock-out valves are typically installed between the instrument air header tap and the air filter regulator, or between the filter regulator and the positioner/solenoid valve supply port. Contact Archer for current model availability and material options.

Best practice: Install one lock-out valve per valve assembly upstream of the air filter regulator. This provides a single lockable isolation point that simultaneously isolates the positioner, solenoid valve, and actuator with one padlock application.

The terms are related but have a specific technical distinction in process plant practice:

 

Air supply block valve: Any manually operated valve (ball, needle, globe) that can isolate the instrument air supply. Standard block valves are used for operational isolation — for example, removing a filter element during operation. They are not necessarily lockable.

 

Lock-out valve (LOTO valve): A specific type of block valve with an integral locking mechanism on the handle — typically a hasp or hole through the handle flange that accepts a padlock. When the padlock is applied in the closed position, the valve physically cannot be opened until the padlock is removed by the person who holds the key. This “positive energy isolation” is the defining requirement of OSHA LOTO.

 

In practice, many plants use the terms interchangeably and specify a lockable ball valve for all instrument air supply points on automated valve assemblies — which satisfies both operational isolation and LOTO requirements simultaneously.

Lock-Out Valves

Pneumatic instrument air isolation for safe maintenance

A lock-out valve (also called a pneumatic lockout/tagout valve, supply isolation valve, or instrument air isolation valve) is a manually operated valve installed in the instrument air supply line to an automated valve assembly. It provides a positive, lockable isolation point that allows maintenance personnel to safely isolate the pneumatic supply — and lock it in the isolated (off) position — before working on the positioner, solenoid valve, limit switch box, or actuator. Why lock-out valves are required:

A standard ¼-turn ball valve or needle valve is not LOTO-compliant unless it has a lockable handle that can accept a padlock. Always specify a lockable lock-out valve for instrument air isolation on all automated valve assemblies.

Archer Automation offers lock-out valves designed specifically for instrument air supply isolation in valve automation applications. These are lockable quarter-turn ball valves with handles that accept a standard padlock through the handle flange — preventing re-opening while the maintenance lock is applied.

Key features of Archer lock-out valves:

Lock-out valves are typically installed between the instrument air header tap and the air filter regulator, or between the filter regulator and the positioner/solenoid valve supply port. Contact Archer for current model availability and material options.

Best practice: Install one lock-out valve per valve assembly upstream of the air filter regulator. This provides a single lockable isolation point that simultaneously isolates the positioner, solenoid valve, and actuator with one padlock application.

The terms are related but have a specific technical distinction in process plant practice:

 

Air supply block valve: Any manually operated valve (ball, needle, globe) that can isolate the instrument air supply. Standard block valves are used for operational isolation — for example, removing a filter element during operation. They are not necessarily lockable.

 

Lock-out valve (LOTO valve): A specific type of block valve with an integral locking mechanism on the handle — typically a hasp or hole through the handle flange that accepts a padlock. When the padlock is applied in the closed position, the valve physically cannot be opened until the padlock is removed by the person who holds the key. This “positive energy isolation” is the defining requirement of OSHA LOTO.

 

In practice, many plants use the terms interchangeably and specify a lockable ball valve for all instrument air supply points on automated valve assemblies — which satisfies both operational isolation and LOTO requirements simultaneously.

Lock-Out Valves

Pneumatic instrument air isolation for safe maintenance

A lock-out valve (also called a pneumatic lockout/tagout valve, supply isolation valve, or instrument air isolation valve) is a manually operated valve installed in the instrument air supply line to an automated valve assembly. It provides a positive, lockable isolation point that allows maintenance personnel to safely isolate the pneumatic supply — and lock it in the isolated (off) position — before working on the positioner, solenoid valve, limit switch box, or actuator. Why lock-out valves are required:

A standard ¼-turn ball valve or needle valve is not LOTO-compliant unless it has a lockable handle that can accept a padlock. Always specify a lockable lock-out valve for instrument air isolation on all automated valve assemblies.

Archer Automation offers lock-out valves designed specifically for instrument air supply isolation in valve automation applications. These are lockable quarter-turn ball valves with handles that accept a standard padlock through the handle flange — preventing re-opening while the maintenance lock is applied.

Key features of Archer lock-out valves:

Lock-out valves are typically installed between the instrument air header tap and the air filter regulator, or between the filter regulator and the positioner/solenoid valve supply port. Contact Archer for current model availability and material options.

Best practice: Install one lock-out valve per valve assembly upstream of the air filter regulator. This provides a single lockable isolation point that simultaneously isolates the positioner, solenoid valve, and actuator with one padlock application.

The terms are related but have a specific technical distinction in process plant practice:

 

Air supply block valve: Any manually operated valve (ball, needle, globe) that can isolate the instrument air supply. Standard block valves are used for operational isolation — for example, removing a filter element during operation. They are not necessarily lockable.

 

Lock-out valve (LOTO valve): A specific type of block valve with an integral locking mechanism on the handle — typically a hasp or hole through the handle flange that accepts a padlock. When the padlock is applied in the closed position, the valve physically cannot be opened until the padlock is removed by the person who holds the key. This “positive energy isolation” is the defining requirement of OSHA LOTO.

 

In practice, many plants use the terms interchangeably and specify a lockable ball valve for all instrument air supply points on automated valve assemblies — which satisfies both operational isolation and LOTO requirements simultaneously.

Archer vs. Competing Products

Topworx · Westlock · Moniteur · Rotork Biffi · Emerson Fisher · ABB · Siemens

Topworx (an Emerson brand) is one of the most widely installed limit switch box lines in North American process plants. Topworx offers the GO Switch and DXP/EXP series, known for their rugged design and proximity sensor options. Archer LSB series products are a direct replacement across the Topworx product range.

FeatureTopworx DXP / EXPArcher LSB-1000 / LSB-3000
Weatherproof option✔ DXP Series, IP65/66✔ LSB-1000, IP66 & IP67 standard
Flameproof option✔ EXP Series, ATEX/IECEx✔ LSB-3000, ATEX/IECEx, IIC T6
Integrated solenoid✔ Available as option✔ LSB-7000 — flameproof + solenoid
Stainless steel housing— Select models✔ LSB-3000 SS316 standard option
Non-contact reed switches✔ Available✔ TTL Tungsten and Rhodium standard
P&F proximity sensors✔ Available✔ NAMUR NJ2-V3 / NBB series
Stock availability (US)— Distributor dependent✔ Two US stock locations, fast ship
EAC / KCs certification— Select models✔ LSB-3000 standard certifications

Archer LSB accessories are direct mechanical replacements for Topworx DXP and EXP assemblies on NAMUR-mounted actuators. The indicator drum color coding and NAMUR bracket dimensions are interchangeable. Contact Archer with your Topworx model number for a direct cross-reference.

Westlock Controls (now part of Curtiss-Wright) is particularly well known for its non-contact magnetic position sensing technology and for the Quadra-Trak and 2200 Series switch boxes, which have significant installed base in refining and chemical plants.

FeatureWestlock 2200 / Quadra-TrakArcher LSB Series
Non-contact sensing✔ Magnetic (Quadra-Trak flagship)✔ Hermetically sealed reed switches (TTL)
Mechanical switch option✔ Available✔ SPDT and DPDT options
Flameproof (Zone 1)✔ ATEX available✔ LSB-3000, ATEX/IECEx IIC T6
ESD integrated option✔ Available✔ LSB-7000
Stainless steel housing✔ Available✔ LSB-3000 SS316
US stock availability— Extended lead times reported✔ In stock, Houston TX, ships fast

A key differentiator: Archer LSB switch boxes are available from stock in Houston for immediate delivery — a significant advantage when a refinery is in shutdown turnaround with same-day replacement requirements. Archer provides direct cross-references to Westlock 2200 and Quadra-Trak configurations. Contact us with your Westlock part number for a replacement recommendation.

Emerson Fisher FIELDVUE DVC6200 is one of the most widely used digital valve controllers in the world, known for excellent diagnostics and deep integration with Emerson DeltaV DCS. However, the DVC6200 uses a piezo valve mechanism and is known to have sensitivity to dirty air and vibration in some plant conditions.

FeatureFisher DVC6200Archer ASD-5000 / 7000
I/P mechanism— Piezo valve (sensitive to dirty air)✔ Diaphragm/torque motor (robust)
Air filtration requirement— 40 micron required✔ 5 micron standard — more forgiving
Vibration tolerance— Sensitive to high vibration service✔ High vibration resistance
Single/double acting— Different models required✔ Same unit for both configurations
Auto-calibration✔ Yes — one touch✔ Yes — one touch
HART communication✔ Yes✔ Yes — HART 7th generation
Profibus / FF✔ Separate DVC6200f model✔ ASD-7000 (HART + FF + Profibus)
ATEX Flameproof (Zone 1)✔ Available✔ ASD-7000
Price point✗ Premium pricing✔ Competitive pricing; fast delivery

The Archer ASD series is particularly compelling as a DVC6200 replacement in high-vibration service (compressor stations, rotating equipment skids) and in plants with older instrument air systems where 40-micron filtration maintenance is unreliable. The ASD uses the same HART DD (Device Descriptor) structure and is configurable with standard HART 375/475 field communicators.

The ABB TZIDC and Siemens SIPART PS2 are both respected European smart positioners widely used in global process plants. Both use piezo valve technology for the I/P stage.

FeatureABB TZIDCSiemens SIPART PS2Archer ASD-5000/7000
I/P mechanismPiezoPiezo✔ Diaphragm/torque motor
Dirty air tolerance40 micron required40 micron required✔ 5 micron — more tolerant
Auto-calibration
HART✔ HART 7
Profibus✔ TZIDC-300✔ PS2-HW✔ ASD-7000
Foundation Fieldbus✔ PS2-FF✔ ASD-7000
US stock availabilityVaries by distributorVaries by distributor✔ In stock, Houston TX
US/Canada focusGlobal productGlobal product✔ US and Canada optimized

The Archer ASD series matches ABB and Siemens on digital functionality while offering superior tolerance to the real plant conditions — dirty air and vibration — that cause piezo-based positioners to degrade over time. For US and Canadian plants, Archer also offers the advantage of Houston-based stock with rapid delivery versus importing European product through distribution channels.

Rotork Biffi (formerly Biffi Italia, acquired by Rotork in 2014) offers both pneumatic actuators and valve accessories including positioners (ICON2000 series) and limit switch boxes for their actuator product line. Biffi is well known in the LNG and offshore markets.

 

Key points of comparison:

Moniteur Devices is a US-based manufacturer of valve position monitors and limit switch boxes with a strong installed base in refining and petrochemical plants, particularly in Texas and the Gulf Coast region. Moniteur is known for its robust designs and US manufacturing.

 

Archer offers a comparable product line with the following distinctions:

Archer accessories are mechanically compatible with NAMUR-mounted Moniteur units and can replace Moniteur switch boxes during turnaround without actuator modification. Contact us for a Moniteur model cross-reference.

Archer vs. Competing Products

Topworx · Westlock · Moniteur · Rotork Biffi · Emerson Fisher · ABB · Siemens

Topworx (an Emerson brand) is one of the most widely installed limit switch box lines in North American process plants. Topworx offers the GO Switch and DXP/EXP series, known for their rugged design and proximity sensor options. Archer LSB series products are a direct replacement across the Topworx product range.

FeatureTopworx DXP / EXPArcher LSB-1000 / LSB-3000
Weatherproof option✔ DXP Series, IP65/66✔ LSB-1000, IP66 & IP67 standard
Flameproof option✔ EXP Series, ATEX/IECEx✔ LSB-3000, ATEX/IECEx, IIC T6
Integrated solenoid✔ Available as option✔ LSB-7000 — flameproof + solenoid
Stainless steel housing— Select models✔ LSB-3000 SS316 standard option
Non-contact reed switches✔ Available✔ TTL Tungsten and Rhodium standard
P&F proximity sensors✔ Available✔ NAMUR NJ2-V3 / NBB series
Stock availability (US)— Distributor dependent✔ Two US stock locations, fast ship
EAC / KCs certification— Select models✔ LSB-3000 standard certifications

Archer LSB accessories are direct mechanical replacements for Topworx DXP and EXP assemblies on NAMUR-mounted actuators. The indicator drum color coding and NAMUR bracket dimensions are interchangeable. Contact Archer with your Topworx model number for a direct cross-reference.

Westlock Controls (now part of Curtiss-Wright) is particularly well known for its non-contact magnetic position sensing technology and for the Quadra-Trak and 2200 Series switch boxes, which have significant installed base in refining and chemical plants.

FeatureWestlock 2200 / Quadra-TrakArcher LSB Series
Non-contact sensing✔ Magnetic (Quadra-Trak flagship)✔ Hermetically sealed reed switches (TTL)
Mechanical switch option✔ Available✔ SPDT and DPDT options
Flameproof (Zone 1)✔ ATEX available✔ LSB-3000, ATEX/IECEx IIC T6
ESD integrated option✔ Available✔ LSB-7000
Stainless steel housing✔ Available✔ LSB-3000 SS316
US stock availability— Extended lead times reported✔ In stock, Houston TX, ships fast

A key differentiator: Archer LSB switch boxes are available from stock in Houston for immediate delivery — a significant advantage when a refinery is in shutdown turnaround with same-day replacement requirements. Archer provides direct cross-references to Westlock 2200 and Quadra-Trak configurations. Contact us with your Westlock part number for a replacement recommendation.

Emerson Fisher FIELDVUE DVC6200 is one of the most widely used digital valve controllers in the world, known for excellent diagnostics and deep integration with Emerson DeltaV DCS. However, the DVC6200 uses a piezo valve mechanism and is known to have sensitivity to dirty air and vibration in some plant conditions.

FeatureFisher DVC6200Archer ASD-5000 / 7000
I/P mechanism— Piezo valve (sensitive to dirty air)✔ Diaphragm/torque motor (robust)
Air filtration requirement— 40 micron required✔ 5 micron standard — more forgiving
Vibration tolerance— Sensitive to high vibration service✔ High vibration resistance
Single/double acting— Different models required✔ Same unit for both configurations
Auto-calibration✔ Yes — one touch✔ Yes — one touch
HART communication✔ Yes✔ Yes — HART 7th generation
Profibus / FF✔ Separate DVC6200f model✔ ASD-7000 (HART + FF + Profibus)
ATEX Flameproof (Zone 1)✔ Available✔ ASD-7000
Price point✗ Premium pricing✔ Competitive pricing; fast delivery

The Archer ASD series is particularly compelling as a DVC6200 replacement in high-vibration service (compressor stations, rotating equipment skids) and in plants with older instrument air systems where 40-micron filtration maintenance is unreliable. The ASD uses the same HART DD (Device Descriptor) structure and is configurable with standard HART 375/475 field communicators.

The ABB TZIDC and Siemens SIPART PS2 are both respected European smart positioners widely used in global process plants. Both use piezo valve technology for the I/P stage.

FeatureABB TZIDCSiemens SIPART PS2Archer ASD-5000/7000
I/P mechanismPiezoPiezo✔ Diaphragm/torque motor
Dirty air tolerance40 micron required40 micron required✔ 5 micron — more tolerant
Auto-calibration
HART✔ HART 7
Profibus✔ TZIDC-300✔ PS2-HW✔ ASD-7000
Foundation Fieldbus✔ PS2-FF✔ ASD-7000
US stock availabilityVaries by distributorVaries by distributor✔ In stock, Houston TX
US/Canada focusGlobal productGlobal product✔ US and Canada optimized

The Archer ASD series matches ABB and Siemens on digital functionality while offering superior tolerance to the real plant conditions — dirty air and vibration — that cause piezo-based positioners to degrade over time. For US and Canadian plants, Archer also offers the advantage of Houston-based stock with rapid delivery versus importing European product through distribution channels.

Rotork Biffi (formerly Biffi Italia, acquired by Rotork in 2014) offers both pneumatic actuators and valve accessories including positioners (ICON2000 series) and limit switch boxes for their actuator product line. Biffi is well known in the LNG and offshore markets.

 

Key points of comparison:

Moniteur Devices is a US-based manufacturer of valve position monitors and limit switch boxes with a strong installed base in refining and petrochemical plants, particularly in Texas and the Gulf Coast region. Moniteur is known for its robust designs and US manufacturing.

 

Archer offers a comparable product line with the following distinctions:

Archer accessories are mechanically compatible with NAMUR-mounted Moniteur units and can replace Moniteur switch boxes during turnaround without actuator modification. Contact us for a Moniteur model cross-reference.

Buying from Archer Automation

Distribution · Stock · Lead times · Support · US & Canada

Archer Automation products are available through our network of qualified distributors and factory-trained representatives across the US and Canada. Our distribution partners are trained on product selection, application engineering, hazardous area certification, and post-sale technical support — ensuring you get the right product, correctly specified, with local service capability.

 

To reach our distribution network or purchase directly:

For engineering contractors, EPCs, system integrators, and OEM valve manufacturers, Archer can establish direct procurement relationships for project-based purchases. Contact us to discuss project pricing, delivery scheduling, and documentation requirements.

Archer Automation maintains inventory at two US stocking locations, specifically structured to support rapid fulfillment for both planned project purchases and emergency replacement situations. Our team understands that plant shutdowns, turnarounds, and unplanned outages cannot wait weeks for imported product.

 

Standard in-stock items (LSB-1000, LSB-3000, EPR, EPL, ASD-5000, FR-10, FR-20, FR-30, AVB series, mounting brackets) typically ship:

For turnaround and emergency situations: Contact Archer directly at (713) 817-3337. We prioritize turnaround orders and will pull from either of our two stocking locations to meet your schedule.

 

Custom configurations (special switch combinations, non-standard enclosure materials, unique certifications, or high-quantity project requirements) may have longer lead times. Contact Archer early in the planning phase for project delivery scheduling.

Two stocking locations mean we can route your order from whichever location is geographically closer to your plant or distributor — reducing transit time for urgent shipments across the continental US and Canada.

Yes — Archer Automation serves both the United States and Canada. Canadian plants, refineries, upgraders, and engineering firms can order directly or through our Canadian distribution network. All relevant certifications for Canada (cULus listings, Canadian Standards Association equivalents) are carried on Archer products.

 

Archer’s primary geographic focus is the US and Canadian process industry market — the Gulf Coast, Midcontinent, Western Canadian oilsands, Ontario refining, and other major industrial regions. This focus means we maintain the right products in stock for North American applications, certifications, and specifications (NPT fittings, UL/CSA certifications, ANSI flange patterns).

 

For international inquiries outside the US and Canada, contact Archer to discuss specific project requirements, certification needs, and logistics.

Yes — all Archer Automation products are shipped with the documentation appropriate to the product and certification level:

Calibration: ASD-5000 and ASD-7000 smart positioners are shipped uncalibrated and are configured by the end user or plant engineer using the integral push-button interface or a standard HART 375/475 field communicator. One-touch auto-calibration completes in minutes on the installed valve — no specialist required. EPR and EPL positioners require simple ZERO/SPAN adjustment during commissioning.

 

For project documentation requirements (material test reports, functional test certificates, third-party inspection), contact Archer early in the project to discuss documentation packages.

Archer Automation products are sold and supported through a network of qualified distributors and factory-trained representatives who are equipped to provide:

The straightforward design philosophy of Archer products — proven mechanical mechanisms, clear ZERO/SPAN adjustments, one-touch auto-calibration on ASD models — means that most service tasks can be performed by plant instrument technicians without specialist support. Detailed installation and maintenance manuals are included with every product.

For technical support questions, contact Archer directly at (713) 817-3337 or sales@archer-automation.com and we will connect you with the appropriate technical resource for your region.

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