Fisher 3710 User manual

D101728X012
Type s 3 710 , 3 72 0 P neumati c P ositioners
Typ
e 3 72 2 C onverter
Incorporates Errata dated August 1994; see page 42
Incorporates Loop Schematics dated December 1994
Figure1. Positioners
W6144/IL
W6058-1/IL
SUPPLY
CONNECTION
    
     
    
     
Instruction Manual
Form 5300
July 1993 Types 3710, 3720, 3722

Types 3710, 3720, 3722
2
Contents
Introduction 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Scope of Manual 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Description 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Type Number Description 3. . . . . . . . . . . . . . . . . . . .
Positioner to Actuator Mountings List 3. . . . . . . . . .
Specifications 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installing the Type 3722 Converter 3. . . . .
Mounting the Positioner 6. . . . . . . . . . . . . . . . .
Connections 10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Supply Connection 11. . . . . . . . . . . . . . . . . . . . . . . . .
Output Connections 12. . . . . . . . . . . . . . . . . . . . . . . .
Instrument Connection 12. . . . . . . . . . . . . . . . . . . . . .
Vent Opening, Purge Option, and Actuator
Vent Connection 12. . . . . . . . . . . . . . . . . . . . . . . . .
Connecting the Purge Tube 13. . . . . . . . . . . . . . . .
Electrical Connection for the Type 3722
Positioner 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Diagnostic Connections 14. . . . . . . . . . . . . . . . . . . . .
Calibration 16 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Setting the Initial Cam Position 16. . . . . . . . . . . . . . .
Zero and Span Adjustments 17. . . . . . . . . . . . . . . . .
Standard or Beacon Indicator Alignment 18. . . . . .
Changing Positioner Action 19. . . . . . . . . . .
Single-Action/Double-Action 19 . . . . . . . . . . . . . . . . .
Direct-Action/Reverse-Action 19 . . . . . . . . . . . . . . . .
Split-Range Operation 20. . . . . . . . . . . . . . . . . . . . . .
Changing the Spool Valve (To Increase Positioner
Output Capacity) 20. . . . . . . . . . . . . . . . . . . . . . . .
Changing the Span Adjuster Assembly (To Change
Positioner Input Range) 21. . . . . . . . . . . . . . . . . .
Principle of Operation 22. . . . . . . . . . . . . . . . . .
Positioner Maintenance 23. . . . . . . . . . . . . . . .
Replacing the Standard or Beacon Indicator 23. . .
Removing the Type 3722 Converter 23. . . . . . . . . .
Removing the Positioner 23. . . . . . . . . . . . . . . . . . . .
Removing the Feedback Arm Assembly 25. . . . . . .
Disassembling the Feedback Arm Assembly
and Span Adjuster Assembly 25. . . . . . . . . . . . . .
Removing the Feedback Shaft (Cam Shaft) 26. . . .
Disassembling the Spool Valve, Action Block,
and Gasket 26. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Disassembling the Input Module and
Summing Beam Assembly 27. . . . . . . . . . . . . . . .
Replacing the Input Module Diaphragm 27. . . . . . .
Assembling the Input Module and Summing
Beam Assembly 28. . . . . . . . . . . . . . . . . . . . . . . . .
Assembling the Spool Valve, Action Block, and
Gasket 29. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Assembling the Feedback Shaft (Cam Shaft) 29. .
Replacing the Feedback Arm Assembly
and Span Adjuster Assembly 30. . . . . . . . . . . . . .
Type 3722 Converter Maintenance 30. . . .
Disassembling the Type 3722 Converter 30. . . . . .
Assembling the Type 3722 Converter 30. . . . . . . . .
Testing the Type 3722 Converter Module 31. . . . .
Parts Ordering 31. . . . . . . . . . . . . . . . . . . . . . . . . . .
Parts Kits 31. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Parts List 31. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Positioner Common Parts 31. . . . . . . . . . . . . . . . . . .
Diagnostic Connections 35. . . . . . . . . . . . . . . . . . . . .
Type 3722 Electro-Pneumatic Converter 36. . . . . .
Positioner Mounting Parts 37. . . . . . . . . . . . . . . . . . .
Introduction
Scope of Manual
This instruction manual includes installation, operation,
calibration, maintenance, and parts ordering informa-
tion for the Type 3710 pneumatic positioner and Type
3720 electro-pneumatic positioner. This manual also
provides field installation and maintenance information
for the Type 3722 electro-pneumatic converter. Refer
to separate instruction manuals for information on the
actuator, control valve, and other accessories.
Only personnel qualified through training or experience
should install, operate, or maintain the positioner. If
there are any questions concerning the instructions in
this manual, contact your Fisher sales office or sales
representative before proceeding.
Description
The Fisher Controls Type 3710 pneumatic positioner
and the Type 3720 electro-pneumatic positioner are
used with either diaphragm actuators (spring return) or
piston rotary actuators (spring return or double-action)
as shown in figure 1. These positioners provide a
valve ball or disk position for a specific input signal.
These positioners can easily be configured to provide
single- or double-action output for Fisher Controls
rotary actuators.
The Type 3710 pneumatic positioner accepts a pneu-
matic input signal. The Type 3720 electro-pneumatic
positioner accepts a milliampere (mA), direct current

Types 3710, 3720, 3722
3
W6059-1*/IL
Figure 2. Mounting the Positioner Base Plate
MOUNTING
SCREW
FEEDBACK
SHAFT
MOUNTING
SCREWS
TIE BAR
EXTENSION
(KEY 44) POSITIONER
MOUNTING
PLATE (KEY 43)
(dc), input signal. Refer to the type number description
for an explanation of type numbers.
The Type 3710 pneumatic positioner provides a valve
position for a standard pneumatic input signal. The
positioner may also be split-ranged. See table 2 for
input signal ranges.
The Type 3720 electro-pneumatic positioner provides
a valve position for a milliampere (mA), direct current
(dc), input signal. The positioner may also be split-
ranged. See table 2.
Type Number Description
The following descriptions provide specific information
on the different positioner constructions. If you do not
know the type number of a specific unit, refer to the
nameplate on the positioner (key 5, figure 26).
Type 3710: A pneumatic rotary valve positioner
Type 3720: An electro-pneumatic rotary valve posi-
tioner consisting of a Type 3710 with a Type 3722
attached.
Type 3722: An electro-pneumatic converter used for
conversion of a 4 to 20 milliampere (mA), direct cur-
rent (dc), input signal to a pneumatic input signal for
the pneumatic positioner. Use this unit in combination
with a Type 3710 positioner to make a Type 3720 po-
sitioner.
Positioner to Actuator Mountings List
The positioner mounts directly to the actuator cover
plate of Fisher Controls Types 1051, 1052, and 1061
actuators. See table 3 for actuator sizes.
Figure 2 shows a positioner ready for mounting on a
Fisher Controls piston rotary actuator. A mounting
plate (key 43) is used to mount the positioner base
plate to Fisher Controls Types 1031, 1032, 1051,
1052, 1061, and 1062 actuators. See table 3 for ac-
tuator sizes.
Specifications
Specifications are shown in table 1.
Installing the T ype 3722 Converter
WARNING
Avoid personal injury from sudden
release of process pressure. Before
mounting the Type 3720 electro-
pneumatic positioner or Type 3722
electro-pneumatic converter:
Disconnect any operating lines pro-
viding air pressure, electric power, or a
control signal to the actuator. Be sure
the actuator cannot suddenly open or
close the valve.

Types 3710, 3720, 3722
4
Table1. Specifications
Unless otherwise specified, the specifications listed
are for all positioner type numbers.
Available Configurations
Refer to the type number description
Input Signal(1)
Type 3710:
Standard: J3 to 15 psig (0.2 to 1.0 bar) or J6 to
30 psig (0.4 to 2.0 bar)
Split-Range: J3 to 9 psig (0.2 to 0.6 bar) and 9 to
15 psig (0.6 to 1.0 bar) or J6 to 18 psig (0.4 to 1.2
bar) and 18 to 30 psig (1.2 to 2.0 bar)
Type 3720:
Standard: J4 to 20 mA dc constant current with
30 V dc maximum compliance voltage
Split-Range: J4 to 12 mA dc or 12 to 20 mA dc
Output Signal(1)
Pneumatic pressure as required by the actuator up
to full supply pressure
Action(2):Field-reversible between Jdirect and
Jreverse within the pneumatic positioner
Equivalent Circuit
Type 3720: 120 ohms shunted by three 5.6 V zener
diodes. See figure 10
Typical Performance(1)(4)
Type 3710 Pneumatic Positioner
Independent Linearity: ±0.5% of output span
Hysteresis: 0.5% of output span
Deadband: 0.3% of input span
Type 3720 Electro-Pneumatic Positioner
Independent Linearity: ±1.0% of output span
Hysteresis: 0.6% of output span
Deadband: 0.35% of input span
Electromagnetic Interference (EMI)(1)
Type 3720: When tested per SAMA Standard
PMC 33.1-1978, change in steady-state deviation is
less than ±1% in an electromagnetic field classified
as 3-abc with a field strength of 30 V/m. Positioner
is tested with cover on and with external wiring in
rigid metal conduit.
Maximum Supply Air Demand(3) (Double-Action
Output)
Standard Spool Valve: 60 psig (4.1 bar) supply,
480 scfh (13 normal m3/hour)
High-Capacity Spool Valve: 60 psig (4.1 bar) sup-
ply, 860 scfh (23 normal m3/hour)
Operating Influences(1)
Supply Pressure Sensitivity: A 10% change in
supply pressure changes the valve shaft position less
than the following percentages of valve rotation:
Type 3710: 1.0% at 60 psig supply pressure
Type 3720: 1.5% at 60 psig supply pressure
Supply Pressure(1)
Minimum Recommended: 5 psig (0.3 bar) above
actuator requirement
Maximum: 150 psig (10.3 bar)
Steady-State Air Consumption(3)
Type 3710:
Standard Spool Valve: 23 scfh (0.61 nor-
mal m3/hour) at 60 psig (4.1 bar) supply pressure
High-Capacity Spool Valve: 28 scfh (0.75 nor-
mal m3/hour) at 60 psig (4.1 bar) supply pressure
Type 3720:
Standard Spool Valve: 30 scfh (0.80 nor-
mal m3/hour) at 60 psig (4.1 bar) supply pressure
High-Capacity Spool Valve: 35 scfh (0.93 nor-
mal m3/hour) at 60 psig (4.1 bar) supply pressure
Operative Temperature Limits(1)
J–40 to 180°F (–40 to 80°C) or J–40 to 250°F
(–40 to 121°C)
Housing Classification for Type 3720
NEMA 3R, IEC 529 IP14; Mounting orientation re-
quires converter vent (key 78, figure 27) to be be-
low horizontal
Electrical Classification for Type 3720
Refer to the Hazardous Area Classification bulletin
for specific approvals
Pressure Connections
1/4-inch NPT female
Conduit Connection for Type 3720
J1/2-inch NPT female (standard) or
JM20 female (optional)
Rotary Valve Rotation
J90 degrees (standard)
Approximate Weight
Type 3710: 4.5 pounds (2.04 kg)
Type 3720: 6.0 pounds (2.72 kg)
1. This term is defined in ISA Standard S51.1:1979.
2. For direct action, an increasing input signal extends actuator rod. For reverse action, an increasing input signal retracts actuator rod.
3. Scfh — standard cubic feet per hour (60°F and 14.7 psia). Normal cubic meters per hour (0°C and 1.01325 bar absolute).
4. Typical valves tested using a Fisher Controls Type 1061 size 30 actuator at 60 psig (4.1 bar) supply pressure. Performance may vary with other actuator types and supply pressures.

Types 3710, 3720, 3722
5
Table 2. Input Signal Range
POSITIONER TYPE
INPUT SIGNAL RANGE
POSITIONER TYPE Pneumatic Electronic
T ype 3710
w/3 to 15 psig span adj. ass’y
(no color coding)
J3 - 15 psig (0.2 - 1.0 bar)
J3 - 9 psig (0.2 - 0.6 bar) and
9 - 15 psig (0.6 - 1.0 bar),
split-ranging
–––
T ype 3710
w/6 to 30 psig span adj. ass’y
(red color coding)
J6 - 30 psig (0.4 - 2.0 bar)
J6 to 18 psig (0.4 - 1.2 bar)
and
18 - 30 psig (1.2 - 2.0 bar),
split-ranging
–––
T ype 3720
–––
J4 - 20 mA, dc
J4 - 12 mA, dc, or 12 - 20
mA,
dc, split-ranging
T able 3. Positioner to Actuator Mountings
POSITIONER T O ACTUA TOR MOUNTINGS
POSITIONER T O ACTUA TOR MOUNTINGS
Direct Mounting to Actuator Cover Plate(1) Mounting Plate Required
SFisher Type 1051, sizes 30(2), 40, and 60
SFisher Type 1052, sizes 30(2), 40, 60, and 70
SFisher Type 1061, sizes 30, 40, 60, and 68
SFisher Type 1031, sizes 26, 33, 45, 60, and 80
SFisher Type 1032, sizes 45, 70, 185, 280, 425,
680, 1125, 1370, 2585, and 4580
SFisher Type 1051, size 33
SFisher Type 1052, sizes 20, 33
SFisher Type 1061, sizes 80, 100
SFisher Type 1066, sizes 20, 27, and 75
1. Includes purge tube option.
2. The size 30 actuator is no longer manufactured by Fisher Controls. The Types 3710, 3720 positioners are available for field installation on existing size 30 actuators.
DUse bypass valves or completely
shut off the process to isolate the valve
from process pressure. Relieve process
pressure on both sides of the valve.
Drain the process media from both
sides of the valve.
DVent the power actuator loading
pressure and relieve any actuator spring
precompression.
DRelieve any supply or output pres-
sure in the existing positioner.
DWhen installing an
electro-pneumatic positioner or
converter in a hazardous area, turn off
control signals until installation is
complete. Be sure all safety barriers,
connections, and the converter housing
cap and O-ring are properly installed
before supplying a control signal to the
unit.
DUse lock-out procedures to be sure
that the above measures stay in effect
while you work on the equipment.
WARNING
The positioner can provide full supply
pressure to any connected equipment.
To avoid personal injury and equipment
damage, make sure supply pressure
never exceeds the maximum safe work-
ing pressure of any connected equip-
ment.
See figure 3.
To change an existing Type 3710 positioner into a
Type 3720 positioner, install a Type 3722
electro-pneumatic converter. The Type 3722
electro-pneumatic converter mounts over the input and
supply connections of the Type 3710 positioner.
1. Be sure all safety procedures have been followed.
Remove the input and supply connections from the
existing Type 3710 base plate and clean the ports.
2. Locate the two O-rings (key 85, figure 27) and
properly lubricate (key 82) them. Place one O-ring in
the recessed area surrounding the input port on the
positioner base plate. Place the other O-ring around
the supply port.

Types 3710, 3720, 3722
6
Figure3. T ype 3722 Electro-Pneumatic Converter
W6145/IL
EXTERNAL
GROUNDING
SCREW
SUPPLY
CONNECTION
3. Locate the two socket head mounting screws (key
84). Properly orient the converter and secure it to the
positioner base plate with the mounting screws. Be
sure the O-rings remain in place while securing the
converter to the positioner base plate.
4. Connect supply pressure to the converter supply
port.
Mounting the Positioner
Typically, a positioner is ordered with an actuator. At
the factory, the positioner is mounted on the actuator
and calibrated. However, a positioner can be order
separately and mounted on an existing actuator.
To field-mount a positioner to an existing actuator, an
actuator cover plate with mounting holes and purge
tube knockout may be required. Check the existing
actuator cover plate. It must have three positioner
mounting holes and, for specific actuators, a purge
tube knockout. See table 3.
If the proper mounting holes are present, perform the
following mounting procedure and then follow the cal-
ibration procedures in this instruction manual. Refer to
the appropriate instruction manuals for actuator and
valve mounting procedures.
WARNING
Avoid personal injury from sudden re-
lease of process pressure. Before
mounting the positioner:
Disconnect any operating lines pro-
viding air pressure, electric power, or a
control signal to the actuator. Be sure
the actuator cannot suddenly open or
close the valve.
Use bypass valves or completely
shut off the process to isolate the valve
from process pressure. Relieve process
pressure on both sides of the valve.
Drain the process media from both
sides of the valve.
Vent the power actuator loading
pressure and relieve any actuator spring
precompression.
Use lock-out procedures to be sure
that the above measures stay in effect
while you work on the equipment.
When installing a positioner or
converter in a hazardous area, turn off
control signals until installation is com-
plete. Be sure all safety barriers, con-
nections, and the converter housing cap
and O-ring are properly installed before
supplying a control signal to the unit.

Types 3710, 3720, 3722
7
WARNING
The positioner can provide full supply
pressure to connected equipment. To
avoid personal injury and equipment
damage, make sure the supply pressure
never exceeds the maximum safe work-
ing pressure of any connected equip-
ment.
Note
Mounting, Actuator Types
The positioner mounts directly to the
actuator cover plate of several Fisher
Controls actuators. See table 3. To
directly mount the positioner to an
existing Fisher Controls actuator, you
must use an actuator cover plate with
three positioner mounting holes and the
5/8-inch purge option knockout plug.
See the parts list for the specific actua-
tor cover plate required above to inte-
grally mount the positioner.
See figures 4, 29 for positioner
mounting drawings.
Note
Replacing An Existing Type 3610
Positioner
To mount the positioner to an actuator
with an existing Type 3610 positioner,
remove the Type 3610 positioner and
replace it with an appropriate metal cov-
er plate and four cap screws. For assis-
tance, contact your Fisher Controls
sales office or representative.
1. See figure 5 for a typical actuator. Remove the ac-
tuator travel indicator machine screws, travel indicator,
and actuator cover cap screws.
Note
Rod End Bearing
When removing the actuator cover plate,
take care not to change the position of
the rod end bearing on the end of the
turnbuckle inside the actuator housing.
2. If necessary, install a new cover plate.
a. Remove the existing cap screws and actuator
cover plate from the actuator housing.
b. Remove the retaining ring (e-clip) and hub from
the cover plate.
c. Install the hub and retaining ring into the new
actuator/positioner cover plate.
Note
Cover Plate Orientation
Position the actuator cover plate so the
positioner mounting holes on the new
cover plate allow placement of the posi-
tioner in the desired orientation.
Actuator cover alignment on the Type
1052 actuator can be aided by moving
the actuator slightly away from its ”up”
travel stop using a regulated air source.
If the hole alignment cannot be obtained
in this manner, temporarily loosen the
cap screws that secure the housing to
the mounting yoke and shift the
housing slightly. Do not completely
travel the actuator while the cover is
removed.
Tighten the actuator cap screws before
continuing.
3. Position the new actuator/positioner cover plate so
the positioner mounting holes on the new cover plate
allow placement of the new positioner in the desired
orientation. Secure the new cover plate to the actua-
tor.
4. Install the positioner tie bar (key 42) in place of the
travel indicator on the actuator hub.
Note
Positioner Mounting Alignment
Before installation of the positioner
mounting plate (key 43), review the
mounting drawings (figures 4, 29).
Properly align the positioner mounting
plate before attaching the mounting
plate to the actuator cover plate. Note
that the three positioner mounting holes
must be aligned to match the three
mounting screws which will pass
through the base of the positioner.

Types 3710, 3720, 3722
8
Figure4. Typical Positioner/Actuator Combinations
42B8466-A/DOC
42B8466-A/DOC

Types 3710, 3720, 3722
9
Figure5. Typical Piston Actuator (T ype 1061)
W6147-1/IL
W6146-1/IL
       
    

Types 3710, 3720, 3722
10
Figure 6. Loosening the Cam Locknut
W5916/IL
5. If the specific actuator requires a positioner
mounting plate (key 43), install the mounting plate
using the cap screws (key 45).
6. Unscrew the four captive cover screws and remove
the cover assembly (key 7) from the positioner.
7. See figure 6. Loosen the cam locknut (key 37) and
rotate the feedback shaft (key 38) as necessary to
align the slot in the feedback shaft end with the tie bar
on the actuator hub. Tighten the cam locknut.
8. Align the positioner with the mounting holes in the
new actuator cover plate or positioner mounting plate.
Be sure that the tie bar fits securely into the feedback
shaft end slot. Secure the positioner to the actuator
cover plate or mounting plate using the (hex) socket
head cap screws (key 46).
9. Before installing the positioner cover, properly align
the valve position indicator (standard, low-profile indi-
cator or optional beacon indicator). Follow the stan-
dard or beacon indicator alignment procedure given in
this instruction manual. Then, install the positioner
cover assembly.
Connections
WARNING
The positioner is capable of providing
full supply pressure to connected equip-
ment. To avoid personal injury and
equipment damage, make sure the sup-
ply pressure never exceeds the maxi-
mum safe working pressure of any con-
nected equipment.
To complete the installation of a positioner, connect
tubing and fittings between the positioner and the ac-
tuator. The fittings, tubing, and mounting parts re-
quired depend on the type number and optional equip-
ment such as filter, regulator, and bypass valve.
Positioner pressure and electrical connection locations
are shown in figure 7. All pressure connections are
1/4-inch NPT female. Use 3/8-inch tubing or 1/4-inch
pipe for all tubing connections.