Damper and Actuator Manual268.1Actuator Literature SectionProduct BulletinD-9502Issue Date0985©1985 Johnson Controls, Inc.1Code No. LIT-1628399PD-9502 PneumaticDamper Actuator PositionerThe D-9502 Pneumatic DamperActuator Positioners areprecision relay devices used toadjust and maintain damperactuators in exact positions onthose applications requiringprecise or otherwise specialdamper positioning. Refer toTable 1 for models available.The basic positioner providesdynamic stabilization and/orsequential control of damperactuators. It is available factoryinstalled on most D-3000 SeriesDamper Actuators. Refer to theappropriate actuator productdata literature for more details.On D-3153 Series Actuators, aspecial positioner mounting kit(D-9502-9) is available forchanging basic D-9502positioner control to two-stageoperation. Refer to InstallationData D-9502-A.1.Depending on the size of theactuator used, up to threeadditional actuators may becontrolled by a singlepositioner/actuator assembly;for example, multiple actuatorsmodulating large or coupleddampers.OperationFeedback from the actuatorshaft (through the positionerspring and lever arm assembly)activates the positioner tocompensate for external forcesat the shaft and holds theactuator at the position dictatedby the controller.Supply air enters the controlchamber of the relay and isadmitted to the actuator whenthe control pressure in the pilotchamber exceeds theestablished starting point. Thispressure causes the actuatorshaft to move. Movement of theshaft is fed back to the relayFig. 1: D-9502 Positioner Installed on D-3153 Series Actuator withUniversal Mounting BracketSpecifications2 D-9502 Product Bulletinthrough the positioner springand lever arm to impose abalancing force against thecontrol pressure. When allforces are in balance, thepositioner will not allow supplyair to pass through to theactuator. The actuator willestablish a position proportionalto the value of the pressure fromthe controller. Any change inshaft position will inbalance therelay, causing air pressure in theactuator to increase or beexhausted to reestablish abalance at the desired shaftposition.Application and DrawingIdentificationOperating RangeThe operating range isdetermined by the span andstarting point adjustments of thepositioner. The lower value ofthe range is the control signalpressure at which the actuatorbegins to stroke. The uppervalue is the control signalpressure at which the actuatorreaches its maximum stroke.The difference between theupper and lower values of thecontrol signal pressure is theoperating span.Operation SpanThe operating span of theD-9502 Positioner is adjustablefrom 3 to 13 PSI (21 to 91 kPA)and is determined by thelocation of the spring in thepositioner spring arm (seeFig. 3). When attached to thehole closest to the positionercover, the spring allows a spanof 3 PSI. When attached to thehole furthest from the cover, thespring allows a span of 13 PSI.D-9502 Product Bulletin 3Starting PointThe starting point is the point atwhich the actuator begins tostroke. It is adjustable form 2 to12 PSIG (14 to 84 kPa) usingthe starting point adjustingscrew located under the cover(see Fig. 3). Turning the screwcounterclockwise will increasethe starting point and clockwisewill decrease the starting point.Note: The sum of the startingpoint pressure and theoperating span must notexceed the supply airpressure to the positioner. Atypical supply pressure isusually between 20 and25 PSIG (140 and 175 kPa).Maintain a starting pointpressure and correspondingoperating span accordingly.MountingThe D-9502 Positioner isfurnished with a mountingbracket for attachment directlyonto the actuator body. Whenmounting the assembly, allowspace for removal of the coverand adjustment of the relay.When a D-3000 Series DamperActuator is ordered with apositioner, the positioner isfactory installed on the actuator(see the appropriate actuatorproduct data literature for moredetails).CalibrationThe following is a typicalexample of how a D-9502Positioner is used to adjust theoperating range and change thespan of a damper actuator.Assume an actuator has aspring range of 8 to 13 PSIG(56 to 91 kPa) resulting in aspan of 5 PSI (35 kPa), and thatit is desirable to use a D-9502Positioner to obtain an operatingrange of 6 to 13 PSIG (42 to91 kPa) resulting in a span of7 PSI (49 kPa). To make theadjustment, refer to Fig. 3 andproceed as follows:1.Attach one end of thepositioner spring to the holein the lever arm whichcorresponds to a 7 PSIspan. The other end of thepositioner spring must berelocated to make thespring perpendicular to thelever arm.2.Apply a controller outputpressure of 6 PSIG to thepositioner.3.Remove the positionercover and turn the startingpoint adjusting screwclockwise until the actuatorjust begins to stroke. Note:The output pressurereading can be takeneither using a pressuregage in the output line orat the hypodermic needletest point on thepositioner body.4.Increase the controlleroutput to 13 PSIG. At thispoint, the actuator shouldbe fully stroked.Note: In some cases,adjusting the starting pointwill affect the operating spanand a different hole in thelever arm will need to beselected.The D-9502 will now position thedamper actuator over a range of6 to 13 PSIG.--Repair Parts Listed on Next Page--4 D-9502 Product BulletinControls GroupFAN 268.1507 E. Michigan StreetDamper and Actuator ManualP.O. Box 423Revision Date 0985Milwaukee, WI 53202Printed in U.S.A.Next >