with spdt v3 microswitches or v3 inductive...

Installation, Operating & Setting Instructions. Westlock 793 Rotary Pneumatic Positioner

With SPDT V3 Microswitches OR V3 Inductive Proximity Sensors

WESTLOCK CONTROLS LTD 22 CHAPMAN WAY, TUNBRIDGE WELLS, KENT, TN2 3EF, ENGLAND. TEL: +44 (0)1892 516277. FAX: +44 (0)1892 516279

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The following document details the installation, operation, setting and maintenance instructions for the Westlock Controls Ltd - 793 Rotary Pneumatic Positioner – introduced 07/2012.

This symbol warns the user of possible danger. Failure to observe this warning may lead to personal injury or death and/or severe damage to equipment. This symbol identifies information about operating the equipment in a particular manner that may damage it or result in a system failure. Failure to observe this warning can lead to total failure of the equipment or any other connected equipment.

This symbol draws attention to information that is essential for understanding the operation and/or features of the equipment.

Contents 1/. Mounting arrangement 2/. Pneumatic connection 3/. Setting procedure (Calibration) 4/. Field wiring (where applicable) 5/. Switch/cam setting (where applicable) 6/. Gauge block assembly 7/. Overall dimension detail 8/. Technical data 9/. Spares list




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1.0 Mounting Instructions. All positioners are designed for direct mounting to actuator and NAMUR mounting (using appropriate Namur bracket not supplied). See figures 1 and 2 below.

Figure 1. Direct mounting to actuator

Figure 2. Mounting using Namur bracket

The M5 internal screws in this configuration are essential as they ‘cap off’ or seal the Housing.




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1.1 For standard direct action operation (increasing signal to open actuator) ensure that the actuator is in the CLOSED position (fully clockwise) and that the flats on the top of the positioner shaft are at right angles to the longitudinal axis of the actuator.

For reverse action (increasing signal to close actuator) ensure that the actuator is in the OPEN position (fully anti-clockwise) and that the flats on the top of the positioner shaft are parallel to the longitudinal axis of the actuator.

1.2 Before mounting the 793 unit it will be necessary to remove the top cover. To do this, completely loosen the 4off M5 socket cap head captive screws in each corner and remove the cover by lifting vertically. Keep the cover safe taking care not to damage the seal detail.

1.3 Fit the positioner on the top face of the actuator according to figure 1 or 2 above. The longitudinal axis of the positioner should be parallel to the actuator cylinder axis. Tighten the internal fixing or blanking screws to a torque value of 18 to 22 lb. Ins.

1.4 Ensure that the feedback cam in the positioner is correctly fitted with the correct range profile bearing against the feedback arm roller. (Positioners are stocked to suit 3 – 15 psig and direct action). For direct action, ensure that anti-clockwise rotation of the positioner shaft, when viewed from above, will cause the cam to compress the spring. For reverse operation ensure that clockwise rotation of the positioner shaft, when viewed from above, will cause the cam to compress the spring.




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2.0 Pneumatic connection

2.1 Connect the air ports as shown in Fig 3 for direct operation and in Fig 4 for reverse operation.




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3.0 Setting Procedure The positioner is pre-set for direct acting prior to leaving the factory. If re-adjustment is necessary to suit a specific actuator, proceed using the following instructions. With the positioner correctly mounted to the actuator, as per fig 1 or 2, and with cover removed, connect the air supply, signal and actuator piping to the positioner as shown in Figs 3 & 4. 3.1 Apply a signal pressure of approximately 9 psig and gradually reduce this to 3

psig. If the actuator just reaches the clockwise limit of rotation as the signal reaches 3 psig, no adjustment is necessary.

3.2 If the actuator does not reach the clockwise limit of rotation at 3 psig, with reference to Fig 5, loosen the locknut and turn the zero-adjusting nut 1/6 of a turn clockwise, when viewed from above. Repeat until zero is correctly achieved.

3.3 If the actuator reaches the clockwise limit of rotation before the signal reaches 3 psig, turn the zero-adjusting nut 1/6 of a turn anti-clockwise, when viewed from above, and repeat until zero is correctly achieved.

3.4 Gradually increase the signal to 15 psig. If the actuator just reaches the counter-clockwise limit of rotation as the signal reaches 15 psig, then no adjustment is necessary.

3.5 If the actuator does not reach the counter-clockwise limit of rotation at 15 psig, this indicates that the spring rate is too high. Loosen the hex socket set screw in the range adjustment collar (see fig 5), hold the collar stationary using a hex wrench (Allen key) and turn the spring slightly clockwise. The zero adjusting nut must now be used to achieve full counter-clockwise rotation

3.6 Conversely, if the actuator reached the counter-clockwise limit of rotation before 15 psig, turn the spring slightly anti-clockwise with respect to the range adjustment collar. Again, re-adjust the zero adjusting nut to achieve full counter-clockwise limit of rotation. The zero and range settings are highly interactive and steps 3.2 to 3.7 must be repeated until zero and span are acceptable.

Note; In steps 3.2 to 3.7, clockwise and anti-clockwise rotations are viewed from the adjusting nut end of the spring.




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After completing the setting procedure, ensure that the hex skt set screw and the locknut are re-tightened. (Hold zero adjusting nut so that it will not move as locknut is tightened).




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4.0 Field Wiring (when switches are present). 4.1 The terminal strip base has been designed to offer easy access for wire

termination to the terminal strip. 4.2 It is not essential to remove the terminal strip to connect the field wiring, but if

required, first remove the terminal strip retaining screw and keep safe as this will be required to secure the terminal strip when complete.

4.3 Lift the terminal strip evenly off of the two base pins and terminate the wiring in

accordance with the wiring diagram which is located on the underside of the cover.

4.4 Reinstall by positioning the terminal strip over the two base pins and pressing

evenly in the direction of the pins. 4.5 Secure with the retaining screw removed in step 4.2. Switch/sensor options; Mechanical Switch – SPDT Form C. Electrical rating – 24, 48, 110 & 240 VAC / 15Amps, 24 VDC / 5 Amps, 48 VDC / 2.5 Amps.




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Alternative Inductive Proximity Sensors. P&F - NJ2-V3-N, NBB3-V3-Z4, NBB2-V3-E2 IFM - IS5026, IS5001, IS0003, IS5003, NS5002 Turck - Bi2-Q10S-AP6X, Bi2-Q10S-YOX Telemecanique - XS7-H10PA340. Wired as follows;

Mechanical V3 Microswitch

Inductive Proximity Sensor




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5.0 Switch cam setting; (See Fig 6). Notes; Either switch can be designated “open” or “closed”. To determine if switch has been activated an electrical continuity tester is recommended. For inductive proximity switches, the appropriate power supply and measuring instrument will be required to sense activation. See switch product literature for recommendations. 5.1 Ensure actuator/valve is in the fully clockwise position. Lift the bottom cam and

rotate clockwise until switch/sensor is activated and then release. The spring will push the cam back onto the splined shaft.

5.2 Operate the actuator to the opposite extreme, push down on the top cam and turn counter-clockwise until the upper switch/sensor is activated.

5.3 Operate the actuator from one extreme to the other several times to ensure that the switches/sensors activate correctly.

FIG 6



WESTLOCK CONTROLS LTD 22 CHAPMAN WAY, TUNBRIDGE WELLS, KENT, TN2 3EF, ENGLAND. TEL: +44 (0)1892 516277. FAX: +44 (0)1892

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6.0 Gauge Block assembly - Retrofit or connection instructions

See Fig 6 6.1 Remove any fittings that currently occupy the positions shown in

diagram, namely: - pressure gauge x 3, supply, exhaust and actuator “open” and “closed” ports.

6.2 With all appropriate surfaces clean and free from any damage, position the two ‘o’ rings (item 8) on gauge manifold block (item 1) before fitting block to existing valve block and secure using two M5 x 30 long screws (item 4).

6.3 Reconnect pneumatic lines using new elbows (item 5) and tube (item 7) and fit gauges (items 2 & 3) as shown with due regard to the notes below.

Notes; a. During installation item 6 – Dust caps, quantity 4, are to be removed and

discarded. b. Ensure when fitting item 5 – Elbow, that the ‘o’ ring supplied with the fitting

is present. c. The tapered thread on the gauges (items 2 & 3) should be sealed into

respective blocks using a proprietary sealant such as PTFE tape or similar.




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Gauge Block assembly - when fitted (or retrofitted or kit) - Fig 6




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Overall dimension detail




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Technical data Input signal

Single range 3 – 15 psi (0.2 – 1.0 bar) standard Split range 3 – 9 psi (0.2 – 0.6 bar) 9 – 15 psi (0.6 – 1.0 bar). Cam characteristics Linear (Standard) Curve 1, range: 3 – 15 psi = 90° (Opt) Curve 2, range: 3 – 9 psi = 65° (Opt) Curve 2, range: 9 – 15 psi = 65° (Opt) Curve 3, range: 3 – 15 psi = 65° Other characteristics on request Supply Media Comp air or inert gas, dust free, oil free with 5 micron inlet filter. Supply pressure 30 – 100 psi (150 psi max) 2 – 8 bar (10 bar max) Air consumption 0.6 cfm in balanced condition With 60 psi (4 bar) supply. Environmental Environmental Temp -5° to +160°F (-20° to +70°C). Mounting and connections Mounting position Any orientation. No limits. Mounting kit Direct or Namur Air connections Supply and output G1/4. (BSPP)

Signal G1/8 (BSPP) Materials of construction

Housing Anodised & electrostatic powder coated aluminium alloy

Diaphragm Nitrile rubber Valve spool Stainless steel

Cover Anodised & electrostatic powder coated aluminium alloy

Mass 4 lbs (1.85 kg)

Options Gauges 1 x Signal air 0 – 30psi (0 – 2 bar) 2 x Supply air 0 – 150psi (0 – 8 bar)

Limit switches See switch section (above)




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793 Positioner Spares List.

with spdt v3 microswitches or v3 inductive...

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