Type 3766 Pneumatic Positioner Type 3767 Electropneumatic ...

1 ApplicationSingle-acting or double-acting positioners for attachment topneumatic control valves. Supplied with a Pneumatic inputsignal to 1 bar or 3 to 15 psi (Type 3766) or an electricinput signal from 0/4 to 20 mA or 1 to 5 mA (Type 3767).Rated travels from to 120 mm or opening angle up to 90 The positioners ensure a fixed assignment between the valvestemposition (controlled variable x) and the Pneumatic or electric in-put signal (reference variable w). They compare the input signalreceived from the control unit with the travel of the controlvalveand, issue the corresponding output signal pressure pst(outputvariable y). A reversing amplifier for double-acting actuatorsproduces two opposed signal features Arbitrary mounting position; suitable for normal orsplit-range operation; excellent dynamic response; negligiblysmall influence of supply air; adjustable proportional band(P-band); adjustable air output capacity; low air supply con-sumption; very insensitive to mechanical vibrations.

2 Low-maintenance compact design Versions for hazardous areas in type of protection "IntrinsicSafety"II 2G Ex ia IIC T6 orII 3G Ex nA II T6 for Zone 2(see "Summary of approvals") Type of protection "Flameproof Enclosure" Ex d withType 3766 Positioner and Type 6116 i/p Converter (Fig. 2) Special version with CrNiMo steel housing available Direct attachment to Type 3277 Pneumatic Actuator (Fig. 4) Attachment to actuators according to IEC 60534-6 (Fig. 3) Attachment to rotary actuators acc. to VDI/VDE 3845 (Fig. 5)Benefits of integral Positioner attachment (Fig. 4) Tight and exact mechanical connection between actuator andpositioner. No misalignment during shipping Concealed linkage protected against touch and external in-fluences to fulfill requirements of accident prevention regula-tions UVV (VBG 5) Simple Pneumatic connection between actuator and Positioner Presetting of the unit: Actuator with positionerOptional pressure gauge for monitoring the input and outputsignal pressure (dial range from 0 to 6 bar and 0 to 90 psi).

3 Refer to Information Sheet T 8350 EN for details on the selectionand application of positioners, converters, limit switches and so-lenoid Type 3766 Pneumatic Positioner Type 3767 Electropneumatic positionerRefer to article code for details on possible Information SheetT 8350 ENEdition January 2010 Data SheetT 8355 ENType 3766 Pneumatic PositionerType 3767 Electropneumatic PositionerFig. 1 Type 3767 Electropneumatic PositionerFig. 3 Attachment acc. toIEC 60534(NAMUR)JISFig. 2 Type 3766 Ex d Positioner withType 6116 i/p ConverterFig. 4 Direct attachment toType 3241-7 ControlValveFig. 5 Attachment toType 3278 Rotary ActuatorPrinciple of operation(Figs.)

4 6 to 8)The only difference between the two positioners is an i/p con-verter unit (E) in the Electropneumatic Positioner . Bothpositioners function according to the force-balance the Type 3767 Electropneumatic Positioner , the control signal(i) flows through the plunger coil (E2) in the field of a permanentmagnet (E1). The force, proportional to the DC current i, is bal-anced against the force of the backpressure at the balancebeam (E3) which is created at the flapper plate (E7) by the jetstream leaving the nozzle (E6). Any changes in the signal causea proportional change in the pressure pesupplied to the pneu-matic control pressure pecreates a force at the measuring diaphragm (5)which is compared to the force of the range spring (4).

5 If thecontrol signal causes the Pneumatic input pressure (pe) or theposition of the lever (1) to change, the diaphragm lever (3) func-tioning as a flapper plate varies the distance to the nozzle ( ). The position of the internal turnboard for the operatingdirection (7) determines which nozzle is Pneumatic booster (10) and the pressure regulator (9) areprovided with supply air. The controlled supply flows againstthe diaphragm lever (3) over the Xp restriction (8) and the noz-zle ( or ). Any changes in the control signal or the posi-tion of the lever (1) cause a variation of pressure both upstreamand downstream of the booster (10). The output signal pressurepstissued by the booster flows over the volume restriction (11) tothe actuator and positions the valve to match the input travel is transmitted to the pick-up lever (1) via the pin ( )in globe valves.

6 Whereas, in rotary valves (Fig. 8), a camfollower roll (20) is attached to the front end of the pick-up lever(1) which follows the rotary motion of a cam disk (22) on the ac-tuator shaft (21). The force of the range spring (4) is changed bythe linear motion of pick-up Positioner must be fitted with a reversing amplifier for at-tachment to double-acting actuators, which generates two op-posed signal pressures (pst1and pst2).The adjustable restrictions Xp (8) and Q (11) are used to opti-mize the control loop. Two adjusting screws ( and ) allowthe adaptation of the control valve to the signal pressure. ZEROand SPAN of the reference variable can be adjusted fordifferent operating modes, such as split-range direction: As the reference variable (pe) increases,the output signal pressure (pst) can either be increasing (direct>>) or decreasing (reverse <>).

7 The operating direction is deter-mined by the position of the turnboard (7) and can be 9 10 11 12epFig. 7 Functional diagram of Type 3767 Positioner2T 8355 9 10 11 12epFig. 6 Functional diagram of Type 3766 Positioner (deflection of pick-up lever in case of directattachment to Type 3277 Pneumatic Actuator)TravelOperating directionControl signal peSupply airOutput signalpressure pstFig. 8 Transmission of rotary motion to the positionerLegend for Figs. 6 to 81 LeverEi/p converter shaftE2 Plunger (>>)E3 Balance (<>)E4 Universal joint3 Diaphragm lever (flapper)E5 Spring4 Range springE6 Nozzle5 Measuring diaphragmE7 Flapper screw (SPAN) screw (ZERO)E9 Damping7 Turnboard for op.

8 DirectionE10 Protective diode8Xp restriction (gain)9 Pressure regulator10 Booster20 Cam follower roll11 Volume restriction Q21 Actuator shaft12 Solenoid valve (optional)22 Cam diskTravelPress. signal peSupply airOutput signalpressure pstOperating direction3T 8355 ENTable 1 Technical data All pressures in bar (gauge)Type 3766 and Type 3767 PositionersTravel rangeDirect attachment to Type 3277 Actuator: .. 30 mmAttachment acc. to IEC 60534 (NAMUR): .. 120 mmOpening angle70 , 75 or 90 depending on cam diskReference variablewType 3766 Signal rangebar (psi) .. 1 bar (3 .. 15 psi)Spanbar (psi) .. bar (6 .. 12 psi) bar (29 psi)Reference variablewType 3767 Signal rangeTwo-wire device, reverse polarity protection0/4.

9 20 mA1 .. 5 mASpan8 .. 20 mA2 .. 4 mAInternal resistance Riat 20 C200 880 Supply airSupply air .. 6 bar (20 .. 90 psi)Air quality acc. toISO 8573-1 (2001-02)Maximum particle size and density: Class 4 Oil contents: Class 3; Pressure dew point:Class 3 or at least 10 K below the lowest ambient temperature to be expectedOutput signal pressure pstCan be limited between 0 .. approx. and 0 .. 6 bar (0 .. approx. 35 and 0 .. 90 psi)CharacteristicLinearDeviation from terminal-based conformity: 1 %Hysteresis %Sensitivity %Operating directionReversibleProportional band .. % (proportional-action coefficient Kp: > 200 .. 40)Air consumptionWith air supply of barWith air supply of 6 barType 3766 230 In/h 230 In/h1)Type 3767 280 In/h 280 In/h1)Air deliveryActuator filled with mn3 mn3/hActuator mn3 mn3/hPermissibleambienttemperature7)Type 3766 Standard C:Optional limit switches/solenoid valve/position transmitterwith plastic cable gland C:Optional limit switches/solenoid valve with metal cable glandLow temperature version C:Optional limit switches/solenoid valve with metal cable glandType 3767 Standard C:Optional limit switches/solenoid valve/position transmitterwith plastic cable gland C.

10 Optional limit switches/solenoid valve with metal cable glandLow temperature version C:Optional limit switches/solenoid valve with metal cable glandInfluenceTemperature: %/10 K Supply air: 1 % between .. 6 barElectromagnetic compatabilityRequirements specified in EN 61000-6-2 and EN 61000-6-3 are metVibrationsNo influence between 10 und 150 Hz and 4 gExplosion protection2)Type of protectionII 2G Ex ia IIC T6 orII 3G Ex nA II T6 for Zone 2 Degree of protectionIP 54 (IP 65 and NEMA 4 possible by fitting a filter check valve (see accessories))WeightApprox. 1 kgAdditional equipmentLimit switches2 inductive proximity switchesType SJ 2-SNControl circuitSpecifications corresponding to the connected switching amplifierHysteresis at rated travel 1 %Solenoid valveInputBinary DC voltage signalNominal signal6 V DC12 V DC24 V DCSignal 0 (off)3) V V VSignal 1 (on)4) V V VMaximum permissible signal28 V25 V32 VInternal resistance Riat 20 C2909 5832 11714 Air consumption in steady stateIn addition to the Positioner Off 60 ln/h On 10 ln/h1)Closing time forrated travel andsignal pressurerange ( )Type 3277 Actuator120 cm 240 cm 350 cm 700 cm.