Instruction Manual For

ACTAIRE LINEAR PNEUMATIC POSITIONERS

Series C40, C42, C44

PRINCIPLE OF OPERATION

Refer to the proper Schematic Illustration for each Series of Positioner. With air pressure applied to the supply port of the Pilot, and the instrument signal at mid-range, the unit is in force balance.

Series C40 (Figure 1)

The Series C40 Positioner is a direct, single acting output, force balance instrument having a characterized feedback suitable for use with spring or fixed air pressure return linear Actuators. The instrument signal acts upon a Diaphragm Assembly creating a force toward the Pilot Valve. An opposing force from the Suppression Spring counteracts this force. The Cantilever Range Spring is in its mid-zero position. An increase in the instrument signal causes an increased force toward the Pilot Valve and moves it open, increasing the output pressure to the Actuator. This increase causes the Stem to extend further and through the Lever Arm, rotates the Cam clockwise. A Cam follower rises and twists the Cantilever Range Spring in the counter clockwise direction, resulting in a force at the end of the Cantilever Range Spring directed away from the Pilot Valve. The Stem continues to extend until the force of the Cantilever Range Spring equals the increase in the instrument signal above its mid-point. A decrease in the instrument signal from its mid-point causes the Diaphragm Assembly to move away from the Pilot Valve and open the Exhaust Seat. As the output pressure decreases, the Stem retracts and rotates the Cam counter clockwise. The Cam Follower drops which twists the Cantilever Range Spring in the clockwise direction, resulting in a force directed toward the Pilot Valve. The Stem continues to retract until the force of the Cantilever Range Spring equals the decrease in the instrument signal below its mid-point.

Series C42 (Figure 3)

The Series C42 Positioner is a double acting output, force balance instrument having a characterized feedback suitable for use with cylinder type linear Actuators. The instrument signal acts upon a Diaphragm Assembly creating a force toward the Direct Pilot Valve. An opposing force from the Suppression Spring counteracts this force. The Cantilever Range Spring is in its mid-zero force position. An increase in the instrument signal causes an increased force toward the Direct Pilot Valve and moves it open, increasing the direct output pressure to one (1) side of the Actuator. At the same time, the direct output pressure is applied to the Reverse Pilot Valve to open its Exhaust Seat, thus decreasing the reverse output pressure to the other side of the Actuator. This causes the Stem to extend further and through the Lever Arm, rotates the Cam clockwise. A Cam Follower rises and twists the Cantilever Range Spring in the counter clockwise direction, resulting in a force at the end of the Cantilever Range Spring directed away from the Direct Pilot Valve. The Stem continues to extend until the force of the Cantilever Range Spring equals the increase in the instrument signal above its mid-point. A decrease in the instrument signal from its mid-point causes the Diaphragm Assembly to move away from the Direct Pilot Valve and open its Exhaust Seat. As the direct output pressure decreases, it causes the Reverse Pilot Valve to open, thus increasing the reverse output pressure. This causes the Stem to retract and rotates the Cam counter clockwise. The Cam Follower drops which twists the Cantilever Range Spring in the clockwise direction, resulting in a force directed toward the Direct Pilot Valve. The Stem continues to retract until the force of the Cantilever Range Spring equals the decrease in the instrument signal below its mid-point.

Series C44 (Figure 2)

The Series C44 Positioner is a reverse, single acting output, force balance instrument having a characterized feedback suitable for use with spring or fixed air pressure return linear Actuators. The instrument signal acts upon a Diaphragm Assembly creating a force away from the Pilot Valve. An opposing force from the Suppression Spring counteracts this force. The Cantilever Range Spring is in its mid-zero force position. An increase in the instrument signal causes an increased force away from the Pilot Valve and opens the Exhaust Seat, decreasing the output pressure to the Actuator. This decrease causes the Stem to retract further and through the Lever Arm, rotated the Cam counter clockwise. A Cam Follower falls and twists the Cantilever Range Spring in the clockwise direction, resulting in a force at the end of the Cantilever Range Spring directed toward the Pilot Valve. The Stem continues to retract until the force of the Cantilever Range Spring equals the increase in the instrument signal above its mid-point. A decrease in the instrument signal from its mid-point causes the Diaphragm Assembly to move toward the Pilot Valve and open the Supply Seat. As the output pressure increases, the Stem extends and rotates the Cam clockwise. The Cam Follower rises which twists the Cantilever Range Spring in the counter clockwise direction, resulting in a force directed away from the Pilot Valve. The Stem continues to extend until the force of the Cantilever Range Spring equals the decrease in the instrument signal below its mid-point.

INSTALLATION

The following information is general in nature since each installation is designed for the particular Actuator being used. Drawings 144-003 and 144-212 show the location of two (2) mounting holes on the rear of the Positioner Housing. The Positioner should be mounted on a sturdy bracket of at least 1/8" thickness or on a yoke or spacer bars. The mounting in the vertical direction should be such that the Lever Arm is horizontal when the Actuator is at the mid-position of its stroke. A clearance of at least plus/minus 2 5/8" should be allowed for rotation of the Lever Arm over the full stroke.

Two (2) types of attachments of the Actuator can be used, a fixed turnbuckle or sliding pin. For the fixed turnbuckle, the Positioner should be mounted so that the turnbuckle is vertical at the mid-position of the stroke. For the sliding pin arrangement, the mounting of the Positioner depends upon the minimum and maximum stroke that the mating bracket is intended to accept.

The force to move the Lever Arm is directed downward for an Actuator whose Stem extends on increase of instrument pressure and is directed upward for an Actuator whose Stem retracts on an increased instrument pressure. The force varies from 0.5 lbs. to 50 lbs. depending upon the stroke and the action of the Cam. The strength of the mounting part should be designed accordingly.

The Lever Arm accepts two (2) ranges of Actuator stroke, ½" - 2" and 1" - 4". Numbers corresponding to the travel desired are marked on the Lever Arm. The marks for ½" - 2" of stroke are associated with Cam Sectors marked A and C. The marks for 1" - 4" of stroke are associated with Cam Sectors marked B and D. Depending upon the Cam in use, the turnbuckle or pin should be adjusted on the Lever Arm to the mark corresponding to the desired stroke mark.

ZERO AND RANGE ADJUSTMENT

With the Positioner properly mounted, the Lever Arm is horizontal when the Actuator is in the mid-position of stroke. The Stem attachment to the Lever Arm should be at the desired stroke mark. Apply an air pressure to the supply port. Make sure this supply pressure does not exceed the safe pressure for the Actuator. Adjust the instrument signal to the mid-point of its span. Turn the Zero Adjust Nut until the center mark of the Cam is vertical and under the Cam Follower. Turning the Zero Adjust Nut clockwise, decreases (Series C40, C42) / increases (Series C44) the output pressure. Reduce the instrument signal to its minimum value of range and note the Actuator position and the position of the minimum mark on the Cam. It should be vertical. Raise the instrument signal to its maximum value of range and note the Actuator position and the position of the maximum mark on the Cam. It should now be in the vertical position. If the Actuator stroke is correct, no further adjustments are necessary. If the stroke is not correct, readjust the attachment of the turnbuckle or pin on the Lever Arm. Moving the attachment inward shortens the stroke and moving the attachment outward lengthens the stroke. Repeat the above steps until the proper stroke and mid-position are obtained. CAUTION: DO NOT EXCEED THE MAXIMUM AND MINIMUM LIMITS OF STROKE BY MORE THAN 10% OF RANGE.

CHANGING THE POSTIONER ACTION

Series C40

The Series C40 Postioner uses a direct, single acting Pilot whose output pressure increases as the instrument signal increases. When used with a direct acting Actuator whose Stem extends on increase in instrument signal, the Cam rotates clockwise as the instrument signal increases causing the Cam Follower to rise. When used with a reverse acting Actuator whose Stem retracts on increase in instrument signal, the Cam rotates counter clockwise as the instrument signal increases causing the Cam Follower to rise. Cam Sectors marked A and B are for direct acting Actuators and Cam Sectors marked C and D are for reverse acting Actuators.

Series C42

The Series C42 Positioner uses a double acting Pilot whose direct output pressure P1 can be connected to the Actuator so that an increase would cause the Stem to extend. At the same time, the reverse output pressure P2 would be connected to the other side of the Actuator. In this form, the overall system would be direct such that the Stem extends on increase in instrument signal pressure. The Cam would rotate clockwise as the Stem extends and the Cam would be placed on Sector A or B. To reverse the action, switch the output pressure connections to the Actuator such that the direct output pressure P1 causes the Stem to retract. At the same time, reverse the Cam so that Sector C or D is used. In this form, the Stem retracts on increase in instrument signal.

Series C44

The Series C44 Positioner uses a reverse, single acting Pilot whose output pressure decreases as the instrument signal increases. When used with a direct acting Actuator whose Stem retracts on increase in instrument signal, the Cam rotates counter clockwise as the instrument signal increases causing the Cam Follower to fall. When used with a reverse acting Actuator whose Stem extends on increase in instrument signal, the Cam rotates clockwise as the instrument signal increases causing the Cam Follower to fall. Cam Sectors marked A and B are for direct acting Actuators and Cam Sectors marked C and D are for reverse acting Actuators.

General

To reverse the direction of feedback, remove the Cam Retaining Nut, hold the Cam Follower up as high as possible and slide the Cam off the Cam Shaft. Replace the Cam as desired and replace the Cam Retaining Nut.

CHANGING THE INSTRUMENT SIGNAL RANGE

The Instrument Signal Range of the Positioner is determined by the Cantilever Range Spring and the Suppression Spring. Before making a change, mechanically block the Cam Follower and Cam so that the Lever Arm is horizontal. This puts the Cantilever Range Spring in its zero force mid-position. Referring to Figure 4, remove the Spring Post Screw from the Spring Post. Remove the Clamp Nut and Clamp Screw holding the Cantilever Range Spring to the Cam Follower and remove the Clamp Plate. Remove the Cantilever Range Spring. Turn the Zero Adjust Nut counter clockwise until it disengages and remove the Suppression Spring. Replace with the new Suppression Spring and replace the Zero Adjust Nut. Reassemble the Cantilever Range Spring to the Cam Follower. Insert the Clamp Screw through the Cam Follower, Cantilever Range Spring, Clamp Plate and the Clamp Washer, and attach the Clamp Nut. Position the Clamp Plate so that its lower edge is parallel with the Cam Follower and securely tighten the Clamp Nut. This should place the Cantilever Range Spring in a vertical position. Tighten the Spring Post Screw attached to the Spring Post which clamps the Cantilever Range Spring in the proper position. The range change is now completed.

POSITIONER BY-PASS OPERATION (Optional for Series C40, C44 only)

If the Positioner is provided with a By-Pass option, the Positioner will be shipped with the By-Pass Lever in the "Positioner" operating position. The "By-Pass" or "Positioner" position is indicated on the By-Pass Lever. With the By-Pass Lever in the "By-Pass" position, the instrument signal is now connected to the output port and thus to the Actuator and the supply port is blocked. In this mode of operation, the four (4) screw can be removed and the Cap/By-Pass Section of the Positioner removed and the Cap/By-Pass Section of the Positioner removed without disrupting operation of the Actuator. The remainder of the Positioner then can be removed from the Actuator and serviced as required.

ELECTRIC LIMIT SWITCHES (Optional)

If the Positioner is provided with Electric Limit Switches, adjust the instrument pressure so that the Cam Shaft rotates counter clockwise to the desired limit of rotation. Rotate the CCW Limit Collar until the pin strikes the Switch Bracket. Rotate slightly further until the CCW Limit Switch trips. Lock the two (2) Set Screws with the Allen Wrench.

Adjust the instrument pressure so that the Cam Shaft rotates clockwise to the desired limit of rotation. Rotate the CW Limit Collar clockwise until the pin strikes the Switch Bracket. Rotate slightly further until the CW Limit Switch trips. Lock the two (2) Set Screws with the Allen Wrench.

Contact the factory if a detailed parts list is required.

CAM CHARACTERISTICS

When you Positioner is shipped from the factory, the proper Cam and Cam Sector are in place according to your order. This selection will be made from three (3) Cams that provide two (2) ranges of stroke, three (3) characteristic curves and provisions to reverse the direction of the feedback.

Figure 5 shows the relationship of Actuator stroke to instrument signal for the three (3) Cam characteristics. Curve 1 is Linear. Curves 2 and 3 are approximately Equal Percentage or Quick Opening depending upon the Sector being used, the action of the Positioner and the action of the Actuator. Each Cam is marked with its part number and each Cam Sector is identified.

There are three (3) marks on the edge of each Cam Sector. These indicate the start, middle and end of the stroke of the Actuator. See "Zero and Range Adjustment" paragraph for proper range adjustment.

DEFINITIONS

Care must be taken in defining action and characteristics in order to avoid misapplication of the Positioner and difficulty in the field. Figure 6 and Figure 7 define the various terms used to describe the Positioner and its use with Actuators and Valves.

TROUBLESHOOTING

If it is suspected that the Positioner is not operating correctly, check the following:

1. Is the Cam in the proper orientation for your application? [Refer to PIB No. 8 (Series C40, C44), PIB No. 12 (Series C42).]

2. Is the Positioner properly mounted? (Refer to the "Installation" paragraph.)

3. Is the turnbuckle in the proper position on the Lever Arm for the desired stroke?

4. Is the Positioner piped correctly?

5. Make sure supply pressure exceeds minimum pressure needed to move the Actuator.

6. Is there an instrument and output pressure at the Positioner? (If the Positioner is equipped with Pressure Gauges, check the instrument pressure reading on the Instrument Gauge and the output pressure reading on the Output Gauge. If the Positioner is not equipped with Pressure Gauges, connect gauges to instrument and output ports and note readings.)

7. Is the Actuator working properly? (Disconnect the supply pressure from the Positioner and connect the supply pressure to the Actuator. Does the Actuator move full stroke?)

If additional help is needed, call our factory or return the Positioner to us for inspection.

WARRANTY

(a) Warranty:

(1) Seller warrants that, at the time of shipment, the products manufactured or repaired by Seller and sold hereunder shall be free from defects in material and workmanship.

(b) Warranty Adjustment:

(1) Seller agrees to repair or furnish a replacement for, but not install, any product which within one (1) year from the date of shipment by Seller shall, upon test and examination by Seller, prove defective within the above warranty. [Pneumatic Positioners shall be warranted for two (2) years from date of shipment.]

(2) If any defect within this warranty period appears, Buyer shall notify Seller immediately.

(3) No product will be accepted for return or replacement without the written authorization of Seller. Independent sales representatives of Seller are not empowered to authorize warranty returns. Upon such authorization and in accordance with instructions from Seller, the product will be returned to Seller, FOB Seller's factory, shipping charges prepaid. Replacement made under this warranty will be shipped FOB Seller's factory at Seller's expense.

(c) Exclusions from Warranty:

(1) THE FOREGOING WARRANTY IS IN LIEU OF AND EXCLUDES ALL OTHER EXPRESSED OR IMPLIED WARRANTIES OF MERCHANTABILITY OF FITNESS FOR ANY PARTICULAR USE.

(2) Seller will not be liable for any special or consequential damages or for loss, damage or expense directly or indirectly arising from the use of the products or any inability to use them either separately or in combination with any other equipment or material or from any other cause.

(3) The warranty does not extend to any product manufactured by Seller which has been subjected to misuse, neglect, accident, improper installation, or to use in violation of instructions furnished by Seller.

(4) Products or components such as charts, tubes, cells, batteries, probes, and the like items which have limited life under normal usage are specifically excluded from this warranty.

(5) The warranty does not extend or apply to any product or component which has been repaired or altered at any place other than at a Seller factory, or by persons not expressly approved in writing by Seller, nor to any product or components, the serial number of which has been removed, defaced or changed.

(6) Components manufactured by any supplier other than Seller shall bear only that warranty made by the manufacturer of that product.