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Fisherr 846 Electro-Pneumatic Transducer

The Fisher 846 electro-pneumatic transducer is a

rugged, field-mountable transducer that accepts an

electrical input signal and converts it to a pneumatic

output signal. Typically, the 4 to 20 mA is converted to

0.2 to 1.0 bar (3 to 15 psi). In the most common

application, the transducer converts an electrical

output signal from a controller to a pneumatic signal

necessary to operate a control valve actuator or

pneumatic positioner.

The transducer includes a deflector/nozzle design

(figure 1) that consists of two nozzles positioned so

that the constant air flow exiting the supply nozzle is

directed at the entrance of the receiver nozzle. Each

nozzle has a large bore of 0.41 mm (0.016 inches),

which provides good resistance to plugging. The input

current signal positions a deflector bar within the

nozzle's flow stream. As the input signal changes, the

deflector bar moves to alter the flow stream to the

receiver nozzle, establishing a pilot pressure at the

receiver nozzle. The pilot pressure, in turn, controls the

booster stage and output of the transducer.

An electronic feedback control network constantly

compares the value of the pneumatic output signal

with the input current signal. A solid-state pressure

sensor is part of the electronics package monitoring

the pneumatic output (figure 3). A comparator circuit

in the control network detects input-output deviations

and adjusts the output by moving the deflector in the

pilot stage to a corrected position. Because of this

feedback network, the transducer can correct for

error-producing effects such as variations in supply

pressure and downstream leakage.

X0234

W6307-1

846 MOUNTED

ON FISHER 667 ACTUATOR

FISHER 846 ELECTRO-

PNEUMATIC TRANSDUCER

846 Transducer

D102127X012

Product Bulletin

62.1:846

March 2015

Summary of content (12 pages)

PAGE 1
Product Bulletin 846 Transducer 62.1:846 March 2015 D102127X012 Fisherr 846 Electro-Pneumatic Transducer The Fisher 846 electro-pneumatic transducer is a rugged, field-mountable transducer that accepts an electrical input signal and converts it to a pneumatic output signal. Typically, the 4 to 20 mA is converted to 0.2 to 1.0 bar (3 to 15 psi).
PAGE 2
Product Bulletin 846 Transducer 62.1:846 March 2015 D102127X012 Specifications Multirange Performance: 9.7 m3/hr (360 scfh) at 2.5 bar (35 psi) supply pressure Input Signal 4-20 mA DC, field adjustable split ranging. Equivalent Circuit Temperature Limits See figure 4 Operating: -40 to 85_C (-40 to 185_F) Storage: -40 to 93_C (-40 to 200_F). Output Signal Standard Performance: J 0.2 to 1.0 bar (3 to 15 psi). Rangeability between 0.1 to 1.2 bar (1 and 18 psi) Multirange Performance: J 0 to 1.
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Product Bulletin 846 Transducer 62.1:846 March 2015 D102127X012 Specifications (Continued) Adjustments Zero and Span: Screwdriver adjustments located in terminal compartment. Remote Pressure Reading (optional) ON or OFF; jumper selectable Frequency Range: 0-10,000 Hz Amplitude: 0.4-1.
PAGE 4
Product Bulletin 846 Transducer 62.1:846 March 2015 Features D102127X012 Figure 1. Detail of Deflector/Nozzle Pilot Stage n Vibration Resistant—The low-mass pilot stage, mechanically damped deflector bar, and rugged construction provide stable performance in vibration. n Large Diameter Nozzles—Large diameter nozzles, free-flow pilot stage design, and large internal pneumatic supply passages provide excellent tolerance to reducing the effects of contaminant buildup and erosion.
PAGE 5
Product Bulletin 846 Transducer 62.1:846 March 2015 D102127X012 Figure 2. Master Module Construction TERMINAL COVER TRANSDUCER HOUSING MASTER MODULE A6326 MODULE COVER STROKE PORT Figure 3. Functional Block Diagram Figure 4. Equivalent Circuit 846 TRANSDUCER 6 VDC 4 TO 20 mA INPUT 50 OHMS ELECTRONIC CIRCUIT MAGNETIC ACTUATOR PILOT STAGE POWER SUPPLY SOLID-STATE PRESSURE SENSOR BOOSTER STAGE 3 TO 15 PSI OUTPUT, TYPICAL Note: The 846 is not a constant resistor in series with an inductor.
PAGE 6
Product Bulletin 846 Transducer 62.1:846 March 2015 D102127X012 Figure 5. Dimensions 67 COVER REMOVAL (2.62) CLEARANCE 1/4-18 NPT SUPPLY CONN 68 (2.69) 59 (2.31) 78 (3.08) 156 (6.15) 29 (1.13) 137 (5.38) MODULE COVER REMOVAL CLEARANCE 119 (4.68) 168 (6.60) 5/16-18 3 PLACES 129 (5.07) 1/2-14 NPT CONDUIT CONN 1/4-18 NPT OUTLET CONN PLUGGED WHEN GAUGE NOT FURNISHED 14B7364-C 6 5.
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Product Bulletin 846 Transducer 62.1:846 March 2015 D102127X012 Figure 6. Dimensions with Optional Fisher 67CFR Filter-Regulator (Yoke Mounted) 67 (2.62) COVER REMOVAL CLEARANCE 13 (0.50) 191 (7.51) 6 (0.25) FOR PROPER MOISTURE DRAINAGE THIS END MUST BE UP 78 (3.08) 1 CENTERLINE OF ACTUATOR MODULE COVER REMOVAL CLEARANCE 137 (5.38) YOKE MOUNTED mm (INCH) Note: 1 The mounting positions shown allow any moisture buildup in the terminal compartment to drain to the signal wire conduit entrance.
PAGE 8
Product Bulletin 846 Transducer 62.1:846 March 2015 D102127X012 Figure 7. Dimensions with Optional Fisher 67CFR Filter-Regulator (Surface/Wall Mounted) 67 (2.62) COVER REMOVAL CLEARANCE 222 (8.76) FOR PROPER MOISTURE DRAINAGE THIS END MUST BE UP 1 89 (3.50) 19 (0.76) 13 (0.50) 89 (3.50) 61 (2.39) MODULE COVER 137 REMOVAL (5.38) CLEARANCE 10/0.
PAGE 9
Product Bulletin 846 Transducer 62.1:846 March 2015 D102127X012 Figure 8. Dimensions with Optional Fisher 67CFR Filter-Regulator (Pipe Stand Mounted) 210 (8.27) 148 (5.82) 67 (2.62) 1/2-14 NPT CONDUIT CONN COVER REMOVAL CLEARANCE 60 (2.38) FOR PROPER MOISTURE DRAINAGE THIS END 2 MUST BE UP 1 13 (0.50) 156 (6.15) 54 (2.51) 67CFR 1/4-18 NPT SUPPLY CONN 1/2-14 NPT OUTLET CONN PLUGGED WHEN GAUGE NOT FINISHED 1/2-14 NPT CONDUIT CONN 262 (10.31) 137 (5.
PAGE 10
Product Bulletin 846 Transducer 62.1:846 March 2015 D102127X012 Table 2. Hazardous Area Classifications for Canada—cCSAus Certification Body Certification Obtained Ex ia Intrinsically Safe Class I Division 1 Groups A,B,C,D T4 per drawing GE59146 CSA XP Explosion-proof Class I Division 1 Groups C,D DIP Dust Ignition-proof Class II III Division I Groups E,F,G T4 NI Non-incendive Class I, Division 2, Groups A,B,C,D T4 Entity Rating Vmax = 30 VDC Imax = 100 mA Ci = 0.
PAGE 11
Product Bulletin 846 Transducer 62.1:846 March 2015 D102127X012 Table 5. Hazardous Area Classifications—IECEx Certificate IECEx Certification Obtained Intrinsically Safe Gas Ex ia IIC T4/T5 Ga Flameproof Gas Ex d IIB T5/T6 Gb Entity Rating Ui = 40 VDC Ii = 200 mA Pi = 1.
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Product Bulletin 62.1:846 March 2015 846 Transducer D102127X012 Neither Emerson, Emerson Process Management, nor any of their affiliated entities assumes responsibility for the selection, use or maintenance of any product. Responsibility for proper selection, use, and maintenance of any product remains solely with the purchaser and end user. Fisher is a mark owned by one of the companies in the Emerson Process Management business unit of Emerson Electric Co.