Fisher 3710, 3720, 3722 Instruction Manual

Instruction Manual
Form 5300
July 1993

Types 3710, 3720, 3722

Type
Typ

Incorporates Errata dated August 1994; see page 42
Incorporates Loop Schematics dated December 1994

s 3

e 3

710

72

, 3

2 C

72

0 P

neumati

onverter

c P

ositioners

W6144/IL

    

     

SUPPLY
CONNECTION

Figure 1. Positioners

W6058-1/IL

    

     

D101728X012

Types 3710, 3720, 3722

Contents

Introduction

Scope of Manual 2.
Description 2

Type Number Description 3.
Positioner to Actuator Mountings List 3.

Specifications 3

Installing the Type 3722 Converter
Mounting the Positioner
Connections

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.

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Assembling the Spool Valve, Action Block, and

Gasket 29.

2.

Assembling the Feedback Shaft (Cam Shaft) 29.
Replacing the Feedback Arm Assembly

and Span Adjuster Assembly 30.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Type 3722 Converter Maintenance

Disassembling the Type 3722 Converter 30.
Assembling the Type 3722 Converter 30.
Testing the Type 3722 Converter Module 31.

3.

Parts Ordering

6.

Parts Kits

10

Parts List

Positioner Common Parts 31.
Diagnostic Connections 35.
Type 3722 Electro-Pneumatic Converter 36.
Positioner Mounting Parts 37.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Introduction

.

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. . .

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. . . .

. . . . .

30.

31.

31.

31.

Calibration

Setting the Initial Cam Position 16.
Zero and Span Adjustments 17.
Standard or Beacon Indicator Alignment 18.

Changing Positioner Action

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
Positioner Maintenance

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.

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. .

16

Scope of Manual

This instruction manual includes installation, operation,
calibration, maintenance, and parts ordering informa­tion for the Type 3710 pneumatic positioner and Type
3720 electro-pneumatic positioner. This manual also

19.

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.

22.

23.

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 pneu­matic input signal. The Type 3720 electro-pneumatic
positioner accepts a milliampere (mA), direct current

2

MOUNTING
SCREW

FEEDBACK
SHAFT

Types 3710, 3720, 3722

TIE BAR

W6059-1*/IL

MOUNTING
SCREWS

Figure

2. Mounting the Positioner Base Plate

EXTENSION
(KEY 44)

(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 split­ranged. 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).

POSITIONER
MOUNTING
PLATE (KEY 43)

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 ac­tuator sizes.

Specifications

Specifications are shown in table 1.

Installing

the T

ype 3722 Converter

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 cur­rent (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 po­sitioner.

WARNING

Avoid personal injury from sudden
release of process pressure. Before
mounting the Type 3720 electro­pneumatic positioner or Type 3722
electro-pneumatic converter:

 Disconnect any operating lines pro­viding air pressure, electric power, or a
control signal to the actuator. Be sure
the actuator cannot suddenly open or
close the valve.

3

Types 3710, 3720, 3722

Table 1. 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:

J 3 to 15 psig (0.2 to 1.0 bar) or J 6 to

30 psig (0.4 to 2.0 bar)

Split-Range:

J 3 to 9 psig (0.2 to 0.6 bar) and 9 to

Operating Influences

Supply Pressure Sensitivity: A 10% change in

supply pressure changes the valve shaft position less
than the following percent ages of valve rotat ion:

Type 3710:
Type 3720:

1.0% at 60 psig supply pressure

1.5% at 60 psig supply pressure

Supply Pressure

Minimum Recommended: 5 psig (0.3 bar) above

actuator requirement
Maximum: 150 psig (10.3 bar)

15 psig (0.6 to 1.0 bar) or J 6 to 18 psig (0.4 to 1.2
bar) and 18 to 30 psig (1.2 to 2.0 bar)

Type 3720:

Standard:

J 4 to 20 mA dc constant current with

30 V dc maximum compliance voltage

Split-Range:

Output Signal

J 4 to 12 mA dc or 12 to 20 mA dc

(1)

Pneumatic pressure as required by the actuator up
to full supply pressure

Action

(2)

: Field-reversible between J direct and

J reverse 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:
Hysteresis:
Deadband:

0.5% of output span

0.3% of input span

±0.5% of output span

Type 3720 Electro-Pneumatic Positioner

Independent Linearity:
Hysteresis:
Deadband:

0.6% of output span

0.35% of input span

Electromagnetic Interference (EMI)

Type 3720:

When tested per SAMA Standard

±1.0% of output span

(1)

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) sup­ply, 860 scfh (23 normal m3/hour)

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.

Steady-State Air Consumption

Type 3710:

Standard Spool Valve:

mal m3/hour) at 60 psig (4.1 bar) supply pressure

High-Capacity Spool Valve:

mal m3/hour) at 60 psig (4.1 bar) supply pressure

Type 3720:

Standard Spool Valve:

mal m3/hour) at 60 psig (4.1 bar) supply pressure

High-Capacity Spool Valve:

mal m3/hour) at 60 psig (4.1 bar) supply pressure

Operative Temperature Limits

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 re­quires converter vent (key 78, figure 27) to be be­low 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

J 1/2-inch NPT female (standard) or
J M20 female (optional)

Rotary Valve Rotation

J 90 degrees (standard)

Approximate Weight

Type 3710: 4.5 pounds (2.04 kg)
Type 3720: 6.0 pounds (2.72 kg)

(1)

(1)

(3)

23 scfh (0.61 nor-

28 scfh (0.75 nor-

30 scfh (0.80 nor-

35 scfh (0.93 nor-

(1)

4

Types 3710, 3720, 3722

Table

2. Input Signal Range

POSITIONER TYPE

T

w/3 to 15 psig span adj. ass’y

w/6 to 30 psig span adj. ass’y

Direct Mounting to Actuator Cover Plate

S Fisher Type 1051, sizes 30
S Fisher Type 1052, sizes 30

S Fisher Type 1061, sizes 30, 40, 60, and 68

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.

ype 3710

(no color coding)

T

ype 3710

(red color coding)

T

ype 3720

(2)

, 40, and 60

(2)

, 40, 60, and 70

T

able 3. Positioner to Actuator Mountings

POSITIONER T

(1)

O ACTUA

Pneumatic Electronic

J 3 - 15 psig (0.2 - 1.0 bar)
J 3 - 9 psig (0.2 - 0.6 bar) and

9 - 15 psig (0.6 - 1.0 bar),
split-ranging

J 6 - 30 psig (0.4 - 2.0 bar)
J 6 to 18 psig (0.4 - 1.2 bar)

and
18 - 30 psig (1.2 - 2.0 bar),
split-ranging

–––

TOR MOUNTINGS

S Fisher Type 1031, sizes 26, 33, 45, 60, and 80
S Fisher Type 1032, sizes 45, 70, 185, 280, 425,

680, 1125, 1370, 2585, and 4580

S Fisher Type 1051, size 33
S Fisher Type 1052, sizes 20, 33
S Fisher Type 1061, sizes 80, 100
S Fisher Type 1066, sizes 20, 27, and 75

INPUT SIGNAL RANGE

J 4 - 20 mA, dc
J 4 - 12 mA, dc, or 12 - 20

mA,

dc, split-ranging

Mounting Plate Required

–––

–––

D 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.

D Vent the power actuator loading
pressure and relieve any actuator spring
precompression.

D Relieve any supply or output pres­sure in the existing positioner.

D When 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.

D Use 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 work­ing pressure of any connected equip­ment.

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.

5

Types 3710, 3720, 3722

W6145/IL

SUPPLY
CONNECTION

EXTERNAL
GROUNDING
SCREW

Figure 3. T

ype 3722 Electro-Pneumatic Converter

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 cal­ibration procedures in this instruction manual. Refer to
the appropriate instruction manuals for actuator and
valve mounting procedures.

WARNING

Avoid personal injury from sudden re­lease of process pressure. Before
mounting the positioner:

 Disconnect any operating lines pro­viding 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 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.

6

Types 3710, 3720, 3722

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 work­ing pressure of any connected equip­ment.

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 actua­tor cover plate required above to inte­grally 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 cov­er plate and four cap screws. For assis­tance, contact your Fisher Controls
sales office or representative.

1. See figure 5 for a typical actuator. Remove the ac­tuator 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 posi­tioner 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 actua­tor.

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.

7

Types 3710, 3720, 3722

42B8466-A/DOC

42B8466-A/DOC

8

Figure 4. Typical Positioner/Actuator Combinations

Types 3710, 3720, 3722

W6147-1/IL

    

W6146-1/IL

       

Figure 5. Typical Piston Actuator (T

ype 1061)

9

Types 3710, 3720, 3722

W5916/IL

Figure

6. Loosening the Cam Locknut

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 indi­cator or optional beacon indicator). Follow the stan­dard 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 equip­ment. To avoid personal injury and
equipment damage, make sure the sup­ply pressure never exceeds the maxi­mum safe working pressure of any con­nected equipment.

To complete the installation of a positioner, connect
tubing and fittings between the positioner and the ac­tuator. The fittings, tubing, and mounting parts re­quired depend on the type number and optional equip­ment 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.

10

Types 3710, 3720, 3722

34B0693-A
B2386-1/IL

Figure

The conduit connection to the converter is 1/2-inch
NPT female with an M20 connection, optional.

The positioner does not have a remote vent connec­tion. Refer to the section on vent opening, purge op­tion, and actuator vent connection for instructions
about a remote vent connection.

Supply Connection

WARNING

Personal injury or property damage may
occur from an uncontrolled process if
the supply medium is not clean, dry,
oil-free, or non-corrosive gas. Industry

7. Connections

instrument air quality standards
describe acceptable dirt, oil, and
moisture content.

Because differences in air quality can
cause a variety of problems in pneumat­ic control operation, Fisher Controls has
no technical basis to recommend the
level of filtration equipment required to
prevent performance degradation of
pneumatic equipment. A filter or filter
regulator capable of removing particles
of 40 microns in diameter should be suf­ficient for most applications.

Use appropriate filtration equipment and
establish a maintenance cycle to moni­tor positioner operation.

See figure 7.

11

Types 3710, 3720, 3722

Connect a clean, dry, oil-free, non-corrosive air source
to the supply connection of the positioner. Recom­mended supply line size is 3/8-inch tubing or 1/4-inch
pipe. A supply air filter or a filter regulator capable of
removing particles 40 microns in diameter is recom­mended. Refer to the positioner specifications, table 1,
for supply pressure requirements.

Supply pressure must not exceed the following limits:

 For the positioner, do not exceed the maximum

pressure rating of 150 psig (10.3 bar).

 For actuator pressure, refer to the appropriate
actuator instruction manual for maximum allowable
pressures.

 For the valve body assembly, do not exceed the
maximum allowable torque or thrust of the specific
valve.

Output Connections

See figure 7.
Use 3/8-inch tubing between the actuator and position-

er.

For diaphragm rotary actuators (single-action out­put from the positioner): Plug OUTPUT A. Connect

OUTPUT B to the diaphragm casing connection.

For piston rotary actuators (double-action output
from the positioner): To extend the actuator stem

with increasing instrument input signal, connect OUT­PUT A to the lower actuator cylinder connection and
OUTPUT B to the upper actuator cylinder connection.
To retract the actuator stem with increasing instrument
input signal, connect OUTPUT A to the upper actuator
cylinder connection and OUTPUT B to the lower ac­tuator cylinder connection.

Instrument Connection

See figure 7.
Use 3/8-inch tubing to connect the output from the

control device to the INSTRUMENT connection on a
pneumatic positioner. For the electro-pneumatic posi­tioner, refer to the electrical connections section.

Vent Opening, Purge Option, and
Actuator Vent Connection

personal injury or property damage
could result from fire or explosion of the
accumulated gas. Personal injury or
property damage could also result from
contact with the flammable, toxic, or
reactive gas.

The positioner/actuator assembly does
not form a gas-tight seal and flammable,
toxic, or reactive gas could leak from
the assembly. Therefore, if the assembly
is enclosed, install a remote vent line
from the enclosure. Furthermore, a re­mote vent pipe from the enclosure alone
cannot be relied upon to remove all haz­ardous gas.

Use adequate ventilation and other nec­essary safety measures. Vent line piping
should comply with local and regional
codes and should be as short as pos­sible with adequate inside diameter and
few bends to reduce case pressure
buildup.

See figure 8.

The positioner does not have an external vent connec­tion. A unit exhausts actuator pressure through a
screened hole (vent opening, figure 7) located in the
positioner base plate. Do not restrict the vent opening.
Restricting the vent opening can produce a pressure
buildup in the positioner case and degrade positioner
performance.

A purge tube (key 58, figure 8) is available as an op­tion when mounting the positioner on selected Fisher
Controls actuators. One end of the purge tube with an
O-ring (key 59) installs in the actuator cover plate. The
other end of the purge tube with an O-ring installs in
the vent opening in the positioner base plate. When
the purge tube is used, it relays actuator exhaust pres­sure from the positioner into the actuator housing.

Within the actuator and positioner assembly, exhaust
pressure takes the following course:

 The actuator exhaust pressure vents from the
actuator through the positioner spool valve into the
positioner case.

 The exhaust pressure then exits the positioner
case through the vent opening.

WARNING

If a flammable, toxic, or reactive gas is
used as the supply pressure medium,

12

 The purge tube carries the exhaust pressure into
the actuator housing.

 The exhaust pressure then purges the actuator
housing and dissipates from the housing.

LONG-BLADED SCREW
DRIVER THROUGH VENT

Types 3710, 3720, 3722

PURGE TUBE (KEY 58)

O-RINGS (KEY 59)

W6073/IL

Figure

8. Mounting the Positioner Base Plate with Purge T

Most actuators manufactured by Fisher Controls do
not have vent openings. The exhaust pressure simply
dissipates from within the actuator housing. However,
the Types 1051, 1052, and 1061 actuators feature an
operational screened vent connection when a metal
access plate is specified for the actuator housing.

When using the purge option, remember: The actuator
and positioner assembly is not airtight. However, if you
use the optional purge tube to connect the positioner
to the actuator and the actuator has a vent opening,
leave open the 1/4-inch NPT vent connection in the
actuator housing to prevent pressure buildup in the
positioner case.

If the 1/4-inch NPT vent connection is available, a vent
line can be installed from the actuator. However, the
valve/actuator/positioner assembly is not airtight.
Maintain adequate ventilation and observe other safe­ty measures.

For help in selecting the purge option for positioner/
actuator combinations, contact your Fisher sales office
or representative.

Connecting the Purge Tube

The positioner mounts directly to the actuator cover
plate of Fisher Controls Types 1051, 1052, and 1061
actuators. See table 3 for actuator sizes.

With an integral mounting, a purge tube (key 58), with
two O-rings (key 59), can be used to relay actuator

ube

exhaust pressure from the positioner into the actuator
housing. If the current actuator cover plate does not
have the positioner mounting holes and purge tube
knockout, order a new cover plate. See the parts list
for the specific actuator cover plate required for each
actuator.

1. The actuator cover plate features a purge tube
knockout. Locate the knockout and use appropriate
tools to open this hole in the cover plate.

2. Install the actuator cover plate and then insert the
purge tube with O-ring into the purge tube hole in the
cover plate.

Note

Purge Tube Installation

When mounting a positioner to an ac­tuator with the purge tube installed,
guide the purge tube into the vent open­ing in the positioner base plate by re­moving the vent screen (key 41) and
then inserting an appropriate tool such
as a screwdriver through the vent open­ing into the purge tube.

When the positioner is secured to the
actuator, install the vent screen.

3. Before mounting the positioner, be sure the second
O-ring is properly fitted to the end of the purge tube.
Use care when mounting the positioner. Be sure the
purge tube with O-ring fits into the vent opening on the
rear of the positioner base plate.

13

Types 3710, 3720, 3722

4. Secure the positioner to the mounting plate using
the (hex) socket head cap screws (key 46).

5. Install the vent screen in the positioner base plate.

Electrical Connection for Type 3720
Positioner

WARNING

In explosion-proof applications, discon­nect power before removing the con­verter housing cap.

In Class I, Division 1 explosion-proof
applications, install rigid metal conduit
and a conduit seal no more than
18 inches (457 mm) from the converter.
Personal injury or property damage may
result from explosion if the seal is not
installed.

A5577*/IL

Figure

9. Field Wiring Diagram

For intrinsically-safe installations, refer
to Fisher loop schematics or to instruc­tions provided by the barrier manufac­turer for proper wiring and installation.

Use the 1/2-inch NPT (or M20 thread) conduit connec­tion for field wiring installation. Refer to figures 9 and
10 when connecting field wiring from the control de­vice to the converter. Connect the positive wire from
the control device to the converter’s positive ( + ) ter­minal and the negative wire from the control device to
the converter’s negative ( – ) terminal.

Do not overtighten the terminal screws. Maximum
torque is 4 pounds force per inch (4 lbfSin.) or

0.45 Newton-meters (0.45 NSm).

Diagnostic Connections

See figure 11.

For diagnostic testing of control valve packages
(valve, actuator, positioner, and accessories), special
connectors and hardware are available. The hardware
required for diagnostic connections includes 3/4-inch
NPT pipe nipples and pipe tees with a 1/8-inch NPT
pipe bushing for the connector. The connector con­sists of a 1/8-inch NPT body and body protector. If the
diagnostic connectors are ordered for a positioner with
gauges, 1/8-inch stems are also included.

Install connectors and hardware between the position­er and the actuator.

21B2335-D
A5578-1/IL

Figure 10. Circuit Schematic

1. Before assembling the pipe nipple, pipe tee, pipe
bushing, actuator piping, and connector body, apply
sealant (key 64) to all threads.

2. Assemble connectors and hardware. Remove stan­dard piping connections, if necessary, and install the
diagnostic connections.

D Type 3720: For a diagnostic connection to the
instrument pressure output from the converter module,
remove the 1/8-inch NPT pipe plug (key 86) from the
Type 3722 converter housing. Apply sealant (key 83)
to the threads of the 1/8-inch NPT connector body and
install it directly into the housing.

D Types 3710, 3720: For diagnostic connections
made up of a pipe nipple, pipe tee, pipe bushing, and
connector body, turn the pipe tee to position the con­nector body for easy access when doing diagnostic
testing.

14

Types 3710, 3720, 3722

13B8743-A
B2414/IL

12B8055-A
B2385/IL

Figure

1

1. Diagnostic Connections

15

Types 3710, 3720, 3722

W5916/IL

Figure

12. Loosening the Cam Locknut

Calibration

The following calibration procedures are for Type 3710
pneumatic positioner adjustment. For the Type 3720
electro-pneumatic positioner, there are no adjustments
within the Type 3722 converter portion of the position­er. All adjustments are accomplished within the pneu­matic portion of the positioner.

WARNING

Avoid personal injury or equipment
damage from sudden release of process
fluid. Before calibration:

 Use bypass valves or completely
shut off the process to isolate the valve
from process pressure.

 Release process pressure from
both sides of the valve.

Setting the Initial Cam Position

Before trying any calibration procedure, follow these
instructions to position the cam (key 36) with respect
to the valve position.

1. Unscrew the four captive cover screws (key 8) and
remove the positioner cover assembly (key 7).

2. See figure 12. Inspect the cam (key 36) and loosen
the cam locknut (key 37).

3. Disconnect the positioner output tubing at the ac­tuator and attach a regulated air source or other
means of positioning the actuator.

4. Position the actuator to correspond with the initial
valve position at minimum instrument input signal.
Stroke the actuator to the final valve position and note
the direction of actuator shaft rotation. Return the ac­tuator to its initial valve position.

5. See figure 13. Position the cam on the roller for the
desired input signal range, for example, 0 - 100%, and
insure that the arrow on the cam corresponds with the
direction of actuator shaft rotation for increasing input
signal. Tighten the cam locknut, leaving a gap of
approximately 0.031 inches (0.80 mm) between the
cam and roller.

6. Reconnect the output tubing to the actuator.

16

A6045/IL

Figure

13. Proper Cam Position

Types 3710, 3720, 3722

1
2

SPAN ADJ ASSY

NAMEPLATE
AREA

SCREENED
VENT
OPENING

ZERO ADJ PIVOT

SPAN ADJ
SHAFT
(THREADED ROD)

ZERO ADJUSTER
LOCK NUT

ZERO ADJUSTER

FEEDBACK

NOTES:

1

THE SPAN ADJ ASSY IS MADE UP OF THE RANGE SPRING, SPAN ADJ SHAFT (THREADED ROD), AND SPAN ADJ KNOB.
THE SPAN ADJ ASSY FEATURES A RED COLOR-CODED RANGE SPRING FOR A 6 TO 30 PSIG INPUT SIGNAL

2

W5947

ARM ASSY

Figure 14. Features and Adjustments

ACTION BLOCK

MOUNTING SCREW HOLE

MOUNTING SCREW HOLE

CAM

SPOOL VALVE

INPUT MODULE

SUMMING BEAM

MOUNTING
SCREW
HOLE

Zero and Span Adjustments

See figure 14.

1. To start this procedure, if necessary, unscrew the
four captive cover screws (key 8) and remove the
cover assembly (key 7).

2. Apply supply pressure.

3. Provide a way to check the input signal. Apply the
minimum input signal. For example:

 For a Type 3710 pneumatic positioner, if the in­put signal range is 3 to 15 psig (0.2 to 1.0 bar), apply
3 psig (0.2 bar).

 For a Type 3720 electro-pneumatic positioner, if
the input signal range is 4 to 20 mA, apply 4 mA to the
Type 3722 converter.

17

Types 3710, 3720, 3722

2

FEEDBACK SHAFT
(CAM SHAFT) (KEY 38)

NOTES:

1

RETAINING RING (E-CLIP) (KEY 12) IS NOT SHOWN.
THE SHAFT OF THE INDICATOR (KEY 15) PASSES THROUGH THE POSITIONER COVER

2

AND FITS OVER THE END OF THE FEEDBACK SHAFT (CAM SHAFT) (KEY 38).

W6061/IL

INDICATOR (KEY 15)

1

Figure

15. Standard Indicator

Note

Key 35

The zero adjustment locknut and zero
adjustment knob are identical parts,
key 35.

4. Loosen the zero adjustment locknut (key 35) and
turn the zero adjustment knob (key 35) until the actua­tor travels the valve to the proper position. This valve
position must correspond to the minimum input signal.

Tighten the zero adjustment locknut before proceeding
to step 5.

5. Slowly increase the input signal until the input
reaches the maximum input signal. Observe the ac­tuator travel and valve position as the input increases.
Determine the actuator/valve position at the maximum
input signal.

6. After observing the actuator/valve travel at maxi­mum input signal, return the input signal to the mini­mum input signal before turning the span adjustment
knob.

 If the actuator/valve travel, observed in step 5,
stopped short of the required valve position at maxi­mum input signal, increase the actuator/valve travel by
rotating the positioner span adjustment knob toward
the zero adjustment nut (key 35) to add active spring
coils to the range spring.

 If the actuator/valve travel, observed in step 5,
reaches the required valve position before the input
signal reaches the maximum input signal, decrease
the actuator/valve travel by rotating the positioner
span adjustment knob away from the zero adjustment

INDICATOR SCALE (KEY 14)

nut (key 35) to remove active spring coils from the
range spring.

7. After turning the span adjustment knob to change
actuator travel, re-zero the positioner using the proce­dure given in steps 4 and 5, above.

8. Increase the input signal until the input reaches the
maximum input signal. Observe the actuator/valve
travel as the input increases. Repeat steps 3 through
8 until the actuator travel corresponds to the input sig­nal range.

9. Properly align the indicator and replace the posi­tioner cover assembly.

Standard or Beacon Indicator Alignment

Note

Indicator

The standard, low-profile indicator con­sists of the indicator cover (key 14), in­dicator (key 15) with internal retaining
ring (e-clip) (key 12), and separate point­er (key 13) recessed into the indicator.
An O-ring (key 15A) fits over the molded
Phillips slot in the indicator to retain the
pointer.

The optional beacon indicator consists
of an external unit (key 10) with external
retaining ring (key 12) and extension
shaft (key 11).

See figure 15.

18

Types 3710, 3720, 3722

1. Locate the indicator/extension shaft (key 11 or key

15) inside the front cover. To align the indicator, rotate
the indicator/extension shaft to match the position of
the feedback shaft extending from the cam (key 36).

2. Install the cover assembly (key 7) so that the indi­cator/extension shaft joins with the feedback shaft.
The standard indicator (key 15) features a molded
Phillips slot that protrudes through the indicator cover
(key 14). If necessary, use a small, Phillips head
screwdriver to align the indicator with the feedback
shaft.

3. Inspect the indicator, pointer, and scale. Make sure
the proper valve position is shown. Follow the proce­dures given in this instruction manual to travel the
valve from fully opened to fully closed. Make sure the
indicator properly displays the valve travel.

If the indicator is not properly aligned, continue with
the following procedure.

4. If the indicator pointer and indicator scale are
slightly out of alignment, loosen the four machine
screws (key 3) that hold the indicator scale to the posi­tioner cover. Turn the scale to properly align it with the
pointer. Tighten the four screws and travel the valve to
confirm proper valve position indication.

5. If the pointer in the standard, low-profile indicator is
positioned in the wrong quadrant, loosen the four ma­chine screws (key 8) that hold the indicator scale (key

14) to the positioner cover. Remove the indicator scale
and O-ring (key 15A). Then, carefully lift the pointer
(key 13) from the indicator (key 15). Place the pointer
in the proper position and re-install the O-ring, indica­tor scale, and screws. Make sure the indicator scale
and pointer are now properly aligned by traveling the
valve.

6. If the internal scale of the beacon indicator is not
properly aligned, remove the four machine screws that
hold the beacon indicator (key 10) to the positioner
cover. Properly orient the beacon cover and replace
the screws. Make sure the beacon cover and scale
are now properly aligned by traveling the valve.

control signal to the actuator and acces­sories. 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 actuator loading pressure.

 Use lock-out procedures to be sure

that the above measures stay in effect
while you work on the equipment.

Single-Action/Double-Action

See figure 16 for positioner output connections. See
figure 18 for the positioner schematic.

Use 3/8-inch tubing between the positioner and actua­tor.

 For single-action output, plug positioner OUTPUT
A. Refer to the actuator instruction manual for the spe­cific connection for positioner OUTPUT B. Connect
positioner OUTPUT B to the actuator connection for
single-action. For Fisher Controls diaphragm actua­tors, this connection is known as the diaphragm casing
connection.

 For double-action output (with direct-action), refer
to the actuator instruction manual for the specific con­nections for positioner OUTPUT A and B. Connect
positioner OUTPUT A to the actuator cylinder connec­tion where actuator air pressure is exhausted during
the initial actuator stroke. Connect positioner OUTPUT
B to the actuator cylinder connection where supply
pressure enters the actuator during the initial actuator
stroke. For Fisher Controls piston actuators, OUTPUT
A connects to the lower actuator cylinder connection
and OUTPUT B connects to the upper actuator cylin­der connection.

Changing Positioner Action

WARNING

Avoid personal injury or equipment
damage from sudden release of process
fluid. Before changing positioner action:

 Disconnect any operating lines pro-

viding air pressure, electric power, or a

Direct-Action/Reverse-Action

This section explains changing the positioner action
from direct to reverse or reverse to direct. With direct­action, the actuator stem extends as the input signal to
the positioner increases. With reverse-action, the ac­tuator stem retracts as the input signal to the position­er increases.

See figure 16.

1. Turn off supply pressure. Reverse the piping con­nections between the actuator and the positioner out­put connections (OUTPUT A and OUTPUT B).

19

Types 3710, 3720, 3722

 6 to 18 psig (0.4 to 1.2 bar)

 18 to 30 psig (1.2 to 2.0 bar)

1. Turn off supply pressure. Remove the positioner
cover assembly (key 7).

2. Loosen the cam locknut (key 37). Rotate the cam
to the desired split-range value: either “0-50%” or
“50-100%”.

3. Before tightening the cam locknut, perform the cam
alignment procedure given in this manual.

4. Turn on supply pressure. Perform the zero and
span adjustment procedure given in this manual. Use
the proper input signal range to match the cam split­range value selected in step 2, above.

5. Replace the positioner cover assembly.

A6056/IL

Figure

16. Output Connections

 For single-action output, disconnect piping from
OUTPUT B. Unplug OUTPUT A and connect the
piping to it. Plug OUTPUT B.

 For double-action output, disconnect piping from
both positioner outputs. Connect piping from OUTPUT
A to OUTPUT B. Connect piping from OUTPUT B to
OUTPUT A.

It may be necessary to bend new lengths of tubing if
rigid tubing is used.

2. After reversing the piping connections, remove the
positioner cover assembly (key 7) and reverse the
cam (key 36). To reverse the cam, unscrew the cam
locknut (key 37). Remove the cam, turn it over, and
reinstall it, making sure the cam is positioned for the
proper input signal range.

3. Set the initial cam position following the cam align­ment procedure given in this manual. Tighten the cam
locknut.

4. Turn on supply pressure. Perform the zero and
span adjustment procedure given in this manual.

5. Replace the positioner cover assembly.

Split-Range Operation

Changing The Spool Valve (To Increase
Positioner Output Capacity)

WARNING

Avoid personal injury or equipment
damage from sudden release of process
fluid. Before changing the spool valve:

 Disconnect any operating lines pro­viding air pressure, electric power, or a
control signal to the actuator and acces­sories. 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 actuator loading pressure.

 Use lock-out procedures to be sure

that the above measures stay in effect
while you work on the equipment.

The positioner can be used for split-range operation
with the input signal from a single control device split
between two positioner/actuator/control valve pack­ages. One positioner will fully stroke one actuator with
an input signal range from:

 3 to 9 psig (0.2 to 0.6 bar)
 9 to 15 psig (0.6 to 1.0 bar)

20

A high-capacity spool valve is available as an option.
Use of the high-capacity spool valve permits increased
actuator stroking speed. See table 2 for outputs for the
standard and high-capacity spool valves.

1. Turn off supply pressure. Release actuator pres­sure. Remove the positioner cover assembly (key 7).

Note

Spool Valve Body, Spool

Handle the spool valve body and spool
with care. The body and spool are
manufactured to precise tolerances and
are prepared as a matched set.

2. Unscrew the two machine screws (key 3) that hold
the spool valve (key 1) onto the action block (key 28).
Remove the spool valve, taking care when separating
the spool from the flexure on the summing beam.

3. Inspect the three O-rings (key 2) found between
the spool valve and the action block. Remove and re­place the O-rings, if necessary.

Note

Spool Valve Body, Spool

Types 3710, 3720, 3722

A6044/IL

Figure

17. Spool V

alve and Summing Beam

Handle the spool valve body and spool
with care. The body and spool are
manufactured to precise tolerances and
are prepared as a matched set.

4. Check the function of the new spool valve to be
installed. The spool should slide freely in the valve
body.

Note

Spool Head, Summing Beam

See figure 17. Before securing the spool
valve, make sure the spool head makes
proper contact with the end of the sum­ming beam.

5. See figure 17. Position the spool valve on the ac­tion block. Make sure the spool extending from the
spool valve body properly engages the summing
beam. Start the two machine screws (key 3) so the
spool valve is loosely held in position on the action
block.

6. Before tightening the machine screws holding the
spool valve, make sure the end of the summing beam
does not contact the spool. Rather, the summing
beam should contact the spool head. If necessary,
adjust the position of the spool valve on top of the ac­tion block, making sure the summing beam does not
bind on the spool. Tighten the two machine screws.

7. Be sure the spool head and summing beam remain
engaged over the entire operating range of the input
module.

Changing the Span Adjuster Assembly
(To Change Positioner Input Range)

The span adjuster assembly (key 4) consists of the
span adjustment knob, span adjustment shaft
(threaded rod), range spring, and washer. The range
spring is welded to the washer and the washer is
welded to the span adjustment shaft.

To identify the span adjuster assembly for 6 to 30 psig
(0.4 to 2.0 bar) input range, red color coding appears
on the range spring.

1. Unscrew the cam locknut (key 37) and remove the
cam (key 36).

Note

Key 35

The zero adjustment locknut and zero
adjustment knob are identical parts,
key 35.

2. Loosen the zero adjustment locknut and turn the
zero adjustment knob (key 35) until the range spring is
free from the summing beam. Move the feedback arm
(key 21) until the range spring falls away from the
summing beam.

Note

Feedback Pivot

The feedback pivot cannot be removed
from the positioner base plate.

21

Types 3710, 3720, 3722

3. Remove the retaining ring (e-clip) (key 27) which
holds the feedback arm assembly (key 21) onto the
feedback pivot. Remove the washer under the retain­ing ring and pull the feedback arm from the pivot.

4. Remove the span adjuster assembly from the feed­back arm by removing the zero adjuster locknut and
sliding the span adjustment shaft (threaded rod) from
the zero adjustment pivot on the feedback arm.

5. Remove the zero adjustment knob from the span
adjuster assembly. Install the zero adjustment knob on
the new span adjuster assembly.

6. Inspect the zero adjustment pivot (key 32). Be sure
it rotates freely. If necessary, replace the zero adjust­ment pivot. Also, if necessary, replace the feedback
arm assembly (key 21) and cam roller (key 23), follow­ing the instructions given in this manual.

7. Install the new span adjuster assembly by sliding
the span adjustment shaft (threaded rod) through the
zero adjustment pivot. Install the zero adjustment lock­nut on the span adjustment shaft.

8. Install the feedback arm assembly with the new
span adjuster assembly by returning the feedback arm
assembly to the feedback pivot. Turn the zero adjust­ment locknut and zero adjustment knob as needed to
fit the range spring to the summing beam. Install the
washer and retaining ring that hold the feedback arm
assembly in position.

9. Install the cam and cam locknut. Be sure the cam
roller on the feedback arm assembly is properly posi­tioned in contact with the cam.

10. Perform the calibration procedures in this manual.

A5944-1/IL

A5944-1/IL

Figure

18. T

ype 3710 Positioner Schematic

One force applied to the summing beam is developed
from the input signal pressure on the diaphragm. The
other force is from the range spring and is proportional
to the position of the feedback lever. The feedback
lever position is determined by the location or rise of
the cam which is attached to the feedback shaft.
When the two opposing forces are equal or at a
steady state, the summing beam holds the spool in a
neutral position. At steady state, a small flow of air
passes from supply through both outputs of the spool
valve to the actuator, holding the actuator at a
constant position. At the same time, another small flow
of air exhausts out each end of the spool valve.

Principle of Operation

See figure 18.

The Type 3710 pneumatic positioner accepts a
pneumatic input signal and the Type 3720
electro-pneumatic positioner accepts a milliampere
(mA), direct current (dc), input signal from a control
device. The Type 3720 positioner uses a Type 3722
converter to provide a pneumatic input to the
pneumatic portion (Type 3710) of the
electro-pneumatic positioner.

The pneumatic portion of the positioner is a
force-balance instrument that provides a control valve
position proportional to a pneumatic input signal. The
balance of opposing forces in the positioner occurs at
the summing beam.

22

When the input pressure is increased to the dia­phragm of the input module, the diaphragm strokes
down, increasing the effective force from the input
module and compressing the range spring. The sum­ming beam moves the spool down in the spool body,
opening output port B to supply air to the left side of
the actuator. At the same time, output port A of the
spool valve opens, allowing the right side of the actua­tor to vent to atmosphere.

The piston in the actuator moves to the right, rotating
the feedback shaft and cam counterclockwise. This
rotation causes the feedback lever to rotate clockwise,
increasing the compression on the range spring.
These rotations continue until the additional force from
the spring balances with the input module force on the
summing beam. When the forces are equal, the sum­ming beam returns to its steady state or neutral posi­tion and the actuator is held at a new position.

Types 3710, 3720, 3722

The Type 3720 electro-pneumatic positioner is a
combination of a Type 3710 pneumatic positioner with
a Type 3722 electro-pneumatic converter. The
converter provides a pneumatic output pressure
proportional to the 4 to 20 milliampere (mA), direct
current (dc), input signal. The pneumatic output
pressure becomes the input signal pressure to the
Type 3710 pneumatic positioner.

Positioner

Maintenance

WARNING

Avoid personal injury or equipment
damage from sudden release of process
fluid. Before performing any positioner
maintenance:

 Disconnect any operating lines pro­viding air pressure, electric power, or a
control signal to the actuator and acces­sories. 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 actuator loading pressure.

 Use lock-out procedures to be sure

that the above measures stay in effect
while you work on the equipment.

Positioner parts are subject to normal wear and must
be inspected and replaced as necessary. The
frequency of inspection and replacement depends
upon the severity of service conditions. The following
procedure describes disassembly and reassembly of
the positioner. When inspection or repairs are
required, disassemble only those parts necessary to
accomplish the task. When reassembly is complete,
adjust the positioner as described in the calibration
section of this manual.

Due to the care Fisher Controls takes in meeting all
manufacturing requirements (heat treating, materials
of construction, dimensional tolerances, and other
characteristics specified by Fisher Controls), use only
replacement parts manufactured by Fisher Controls.

Replacing the Standard or Beacon
Indicator

1. Remove the positioner cover assembly (key 7).

2. Remove the four machine screws (key 8) that hold
the indicator scale (key 14) to the positioner cover.
Remove any other external indicator parts such as the
pointer (key 13).

Note

Indicator

The standard, low-profile indicator uses
a retaining ring (e-clip) (key 12) inside
the positioner cover. The retaining ring
holds the indicator. After removing the
external scale, remove the internal re­taining ring to free the indicator.

The optional beacon indicator uses a
retaining ring (e-clip) (key 12) on the
outside of the positioner cover. The re­taining ring holds the extension shaft.
After removing the beacon indicator, re­move the external retaining ring to free
the extension shaft.

3. Remove the internal or external retaining ring that
holds the indicator/extension shaft. Remove the indi­cator/extension shaft from the positioner cover.

4. Install the new indicator/extension shaft and secure
it with the retaining ring. Install other indicator parts
and properly align the indicator using the procedure
given in this instruction manual.

Removing the Type 3722 Converter

See figure 19.

1. Be sure all safety procedures have been followed.
Remove the input wiring and supply connection from
the installed Type 3722 housing.

2. Remove the two mounting screws (key 84) and
carefully separate the converter from the positioner
base plate. Locate the two O-rings (key 85) and
inspect them. Save or replace as necessary.

3. Be sure the input and supply ports in the positioner
base plate are clean. Apply sealant (key 64) to the
threads of any pipe nipples or other connectors to be
installed in the ports in the positioner base plate. Con­nect pneumatic input and supply pressure to the posi­tioner, if necessary.

Removing the Positioner

1. If you are planning to remove a Type 3720
positioner, be sure to turn off electric power to the
Type 3722 converter. Disconnect field wiring. Release
all pressure to the positioner. Disconnect the supply,
instrument, and output tubing.

23

Types 3710, 3720, 3722

W6149/IL

      

W6148/IL

Figure

24

    

  

19. Removing the Converter Mounting Screws

2. Unscrew the four captive cover screws (key 8) and
remove the positioner cover assembly (key 7).

3. Unscrew the three socket head screws (key 46)
and remove the positioner.

4. Inspect the feedback tie bar (key 42) attached to
the actuator hub. If necessary, unscrew the machine
screws (key 47) and remove the tie bar.

Removing the Feedback Arm Assembly

1. Unscrew the cam locknut (key 37) and remove the
cam (key 36).

Note

Key 35

The zero adjustment locknut and zero
adjustment knob are identical parts,
key 35.

2. Loosen the zero adjustment locknut and turn the
zero adjustment knob (key 35) until the range spring is
free from the summing beam. See figure 20. Move the
feedback arm (key 21) until the range spring falls away
from the summing beam.

Types 3710, 3720, 3722

W6062/IL

Figure

20. Cam Removed; Range Spring Free

From Summing Beam

Note

Note

Feedback Pivot

The feedback pivot cannot be removed
from the positioner base plate.

3. Remove the retaining ring (e-clip) (key 27) which
holds the feedback arm (key 21) onto the feedback
pivot. Remove the washer under the retaining ring and
pull the feedback arm from the pivot.

4. Remove the flanged bearing (key 22) from the
feedback pivot or from the feedback arm. Inspect and
replace the bearing, if necessary.

Disassembling the Feedback Arm
Assembly and Span Adjuster Assembly

Note

Key 35

The zero adjustment locknut and zero
adjustment knob are identical parts,
key 35.

Red Color Coding, Span Adjuster As­sembly

To identify the span adjuster assembly
for 6 to 30 psig (0.4 to 2.0 bar) input
range, red color coding appears on the
range spring.

1. Remove the feedback arm assembly and flanged
bearing (key 22) from the feedback pivot in the posi­tioner base plate. Then, remove the span adjuster as­sembly (key 4) by unscrewing the zero adjuster lock­nut (key 35) and sliding the span adjustment shaft
(threaded rod) from the zero adjustment pivot on the
feedback arm (key 21).

2. Inspect the flanged bearing. If the bearing shows
signs of wear or damage, replace it.

3. Inspect the zero adjustment pivot. Be sure the pivot
rotates freely. If necessary, remove the retaining ring
(e-clip) (key 34), washer (key 33), and zero adjust­ment pivot (key 32).

4. After removing the retaining ring, washer, and
pivot, inspect the needle bearing (key 25). The needle
bearing is pressed into the feedback arm. If the needle
bearing must be replaced, replace the feedback arm
assembly (key 21).

5. If necessary, replace the retaining ring, washer,
and zero adjustment pivot.

25

Types 3710, 3720, 3722

SPOOL VALVE
BODY

SPOOL VALVE
BODY

SPOOL

W5917*/IL

Figure

21. Spool V

6. Be sure the cam roller (key 23) turns freely. If nec­essary, remove the shoulder screw (key 24) and cam
roller from the feedback arm and replace them.

Removing the Feedback Shaft
(Cam Shaft)

1. Unscrew the cam locknut (key 37) and remove the
cam (key 36).

2. Remove the retaining ring (e-clip) (key 40) and
washer (key 39) that hold the feedback shaft (key 38)
in place.

3. Grasp the feedback shaft where it extends from the
back of the positioner base plate. Pull the feedback
shaft from the base plate, being careful not to scratch
the outside diameter of the shaft.

4. Inspect the spacer (key 69) on the shaft. Inspect
the flanged bearings (key 17) in the positioner base
plate. If the spacer or bearings show signs of wear or
damage, replace them. When re-installing the feed­back shaft, spacer, and bearings, be sure the shaft
rotates freely.

alve Body and Spool

Disassembling the Spool Valve, Action
Block, and Gasket

Note

Spool Valve Body, Spool

See figure 21. Handle the spool valve
body and spool with care. The body and
spool are manufactured to precise
tolerances and are prepared as a
matched set.

1. Unscrew the two machine screws (key 3) that hold
the spool valve (key 1) onto the action block (key 28).
Remove the spool valve, taking care when separating
the spool from the flexure on the summing beam.

2. Inspect the three O-rings (key 2) found between
the spool valve and the action block. Remove and re­place the O-rings, if necessary. Lubricate (key 63) O­rings before installation.

3. Unscrew the four machine screws (key 3) that hold
the action block onto the positioner base plate. Lift off
the action block and inspect the gasket (key 29) un­derneath it. Replace the gasket, if necessary.

4. Check the function of the spool valve. The spool
should slide freely in the valve body. Clean the spool
valve or replace it.

26

W5913/IL

Types 3710, 3720, 3722

Figure

22. Separating the Summing Beam Assembly from the Input Module

Disassembling the Input Module and
Summing Beam Assembly

1. Remove the four machine screws (key 3) that hold
the input module assembly (key 30) to the positioner
base plate. If the spool valve has not been removed,
use care when lifting off the input module and sum­ming beam assembly. Be sure to properly separate
the spool from the summing beam flexure.

2. Inspect the one O-ring (key 31) in the positioner
base plate. Replace it, if necessary.

CAUTION

Avoid damage to the diaphragm
(key 30B) when removing the machine
screw (key 30E) that joins the
diaphragm connector and the summing
beam assembly. Use a wrench or other
tool to hold the diaphragm connector
while removing the machine screw.

3. Remove the machine screw (key 30E) holding the
diaphragm connector to the summing beam assembly,
taking care not to twist the diaphragm connector and
diaphragm. Use a wrench or other tool to hold the dia­phragm connector while removing the machine screw.

4. See figure 22. Separate the summing beam as­sembly from the input module by removing one of the
two machine screws (key 20) that hold the flexure re­tainers which join the summing beam flexure to the
input module housing.

Replacing the Input Module Diaphragm

See figure 23.

1. After removing the input module, remove the four
machine screws (key 20) that hold the input module
housing together. Remove the diaphragm cover.

 Note the orientation of the diaphragm (key 30B)

inside the input module.

 Note the raised center circular area (convolution)

of the diaphragm.

 Note the orientation of the diaphragm plates. The
diaphragm plates support the diaphragm and act as
travel stops. When assembling the input module, be
sure the diaphragm plates are properly positioned.

 Pull out the assembly (diaphragm, diaphragm
plates, and diaphragm connector).

2. Grasp the diaphragm connector with a wrench or
other appropriate tool and unscrew the machine screw
(key 30F) on the opposite side of the diaphragm. Re­move the diaphragm plates and discard the dia­phragm.

27

Types 3710, 3720, 3722

W5915/IL

Figure

23. Input Module Diaphragm and Diaphragm Housing

3. See figure 24. Position the new diaphragm
(key 30B) between the diaphragm plates (key 30C).
Be sure the diaphragm convolution is properly oriented
between the diaphragm plates. Attach the diaphragm
connector (key 30D) with the machine screw
(key 30F).

4. Position the diaphragm assembly inside the input
module housing using the alignment pins. Replace the
diaphragm cover and secure it to the input module
housing with the four machine screws (key 20).

Assembling the Input Module and
Summing Beam Assembly

1. Position the summing beam and input module
housing. Place the flexure over the alignment pins ex­tending from the flexure and input module. Secure the
flexure by placing the two flexure retainers over the
alignment pins extending through the flexure. Install
the two machine screws (key 20) that hold the flexure
retainers.

CAUTION

Avoid damage to the diaphragm
(key 30B) when installing the machine
screw (key 30E) that holds the dia-

A6043/IL

Figure

24. Assembly of Input Module

phragm connector to the summing
beam assembly. Use a wrench or other
tool to hold the diaphragm connector
while installing the machine screw.

28

2. Install the machine screw (key 30E) that connects
the summing beam flexure to the diaphragm connec­tor, taking care not to twist the diaphragm connector
and diaphragm (key 30B). Use a wrench or other tool
to hold the diaphragm connector while installing the
machine screw.

3. Inspect the one O-ring (key 31) in the positioner
base plate. Replace it, if necessary. Properly lubricate
(key 63) the O-ring.

Note

Spool Head, Summing Beam

See figure 25. Before securing the input
module and summing beam assembly,
make sure the end of the summing
beam does not come in contact with the
spool shaft. Instead, the end of the sum­ming beam should engage the spool
head.

4. See figure 25. Properly position the input module
and summing beam assembly on the positioner base
plate using the alignment pins on the input module. If
the spool valve (key 1) has not been removed, use
care when positioning the input module and summing
beam assembly. Make sure the spool extending from
the spool valve body properly engages the summing
beam flexure.

5. Secure the assembly with the four machine screws
(key 3).

Assembling the Spool Valve, Action
Block, and Gasket

1. Place the action block gasket (key 29) on the
mounting area found on the positioner base plate.
Place the action block (key 28) on the gasket and se­cure it to the base plate using the four machine screws
(key 3).

2. Inspect the three O-rings (key 2) found between
the spool valve (key 1) and the action block. Replace
the O-rings, if necessary.

Types 3710, 3720, 3722

A6044-1/IL

Figure

25. Spool V

Spool Valve, Summing Beam

See figure 25. Before securing the spool
valve, make sure the spool head makes
proper contact with the end of the sum­ming beam.

4. See figure 25. Position the spool valve on the ac­tion block. Make sure the spool extending from the
spool valve body properly engages the summing
beam. Start the two machine screws (key 3) so the
spool valve is loosely held in position on the action
block.

5. Before tightening the machine screws holding the
spool valve, make sure the end of the summing beam
does not contact the spool. Rather, the summing
beam should contact the spool head. If necessary,
adjust the position of the spool valve on top of the ac­tion block, making sure the summing beam does not
bind on the spool. Tighten the two machine screws.

alve and Summing Beam

Note

Note

Spool Valve Body, Spool

See figure 21. Handle the spool valve
body and spool with care. The body and
spool are manufactured to precise
tolerances and are prepared as a
matched set.

3. Be sure the spool valve is ready for service. Clean
or replace it, if necessary.

6. Be sure the spool head and summing beam remain
engaged over the entire operating range of the input
module.

Assembling the Feedback Shaft
(Cam Shaft)

1. Inspect the feedback shaft (key 38). Be sure the
shaft is free from any damage. Inspect the flanged
bearings (key 17) and spacer (key 69). Replace, if
necessary.

29

Types 3710, 3720, 3722

2. Properly install the flanged bearings in the position­er base plate. Install the spacer on the feedback shaft.
Then, insert the shaft with spacer through the bearings
and base plate. Make sure the feedback shaft rotates
freely.

3. Install the washer (key 39) and retaining ring (e­clip) (key 40) that hold the feedback shaft in place.

4. Attach the cam (key 36) and cam locknut (key 37).

5. Set the initial cam position following the procedures
given in this manual, if necessary.

Replacing the Feedback Arm Assembly
and Span Adjuster Assembly

Note

Key 35

The zero adjustment locknut and zero
adjustment knob are identical parts,
key 35.

Note

Red Color Coding, Span Adjuster

Assembly

To identify the span adjuster assembly
for 6 to 30 psig (0.4 to 2.0 bar) input
range, red color coding appears on the
range spring.

1. Make sure the zero adjustment knob (key 35) is
installed on the span adjustment shaft (threaded rod)
before installation into the zero adjustment pivot.
Install the span adjustment assembly by sliding the
threaded rod through the zero adjustment pivot on the
feedback arm. Install the zero adjuster locknut on the
threaded rod.

2. Install the cam roller (key 23) and shoulder screw
(key 24). Be sure the cam roller rotates freely.

3. Place the flanged bearing (key 22) and feedback
arm assembly on the feedback pivot. Place the wash­er (key 26) on the pivot and install the retaining ring
(e-clip) (key 27) to secure the feedback arm on the
feedback pivot.

4. If necessary, attach the cam (key 36) and cam
locknut (key 37) to the feedback shaft.

5. Perform the calibration procedures in this manual.

Type 3722 Converter
Maintenance

Disassembling the Type 3722 Converter

See figure 26 for key number locations.

1. Turn off electrical power to the converter. Release
all supply pressure from the positioner.

2. Remove the cap (key 72) and disconnect the field
wiring from the terminal block.

 If a grounding wire is used inside the housing
compartment, disconnect the wire from the interior
housing ground screw (key 81).

 If an exterior grounding wire is used, disconnect
the grounding wire from the external ground screw
(key 81).

3. To remove the converter module, remove the two
screws (key 80) and pull the module out of the hous­ing. Inspect the O-ring (key 77) and replace it, if nec­essary.

 If you are removing the converter assembly from
the pneumatic positioner, continue with steps 4
through 6. Or:

 If you are replacing the converter module only,
obtain a replacement converter module and refer to
the procedure for assembling the converter. After re­placing the converter module, calibrate the pneumatic
portion of the positioner by performing the calibration
procedures. There is no converter module calibration.

4. Disconnect the supply tubing, output tubing, and
conduit from the converter.

5. Remove the two socket head screws (key 84) and
remove the converter from the positioner base plate
(key 16, figure 26). Inspect the two O-rings (key 85)
and replace them if necessary. Apply lubricant
(key 82) to the O-rings before replacement.

Assembling the Type 3722 Converter

Refer to figure 27 for key number locations, unless
otherwise indicated, while assembling the converter. If
the converter was removed from the pneumatic posi­tioner, re-install it using the following instructions.

1. Inspect the O-rings (key 85) and replace, if neces­sary. If the O-rings are in good condition, apply lubri­cant (key 82) to the O-rings and install them in the re­cessed areas surrounding the input and supply ports
on positioner base plate (key 16, figure 26). Be sure
the O-rings remain in place.

30

Types 3710, 3720, 3722

2. Apply sealant (key 64 or 83) to the two socket head
screws (key 86). Then, properly align the converter
and attach it to the positioner base plate using the
socket head screws. Be sure the O-rings remain in
place. Tighten the socket head screws.

3. Apply sealant (key 64 or 83) and install pipe bush­ings (key 68), pipe tees (key 56), gauges (key 53, 54,
or 55), pipe plugs (key 57 or 86), tire valves (key 62),
or diagnostic connectors as applicable to the convert­er.

4. If the converter module was removed from the
housing, apply lubricant (key 82) to the O-ring
(key 77) and insert the converter module into the
housing.

5. Replace the two screws (key 80) and tighten them.

6. Connect the supply tubing, output tubing, and con­duit to the converter.

7. Connect the wiring to the terminal block by using
installation procedures.

 If an internal grounding wire is used inside the
housing compartment, connect the wire to the internal
housing ground screw (key 81).

 If an exterior grounding wire is used, connect the
grounding wire to the exterior ground screw (key 81).

8. Inspect the O-ring (key 79) inside the converter cap
(key 72). Replace, if necessary. Lubricate (key 82) the
O-ring and install it inside the cap.

9. Lubricate (key 87) the threads of the cap and re­place it.

10. If the converter module was replaced, calibrate
the pneumatic portion of the positioner by performing
the procedures in the calibration section of this manu­al. Do not attempt to calibrate the converter module.
There are no converter module adjustments.

3. If necessary, replace the converter module and test
the new module. Then, calibrate the pneumatic portion
of the positioner by performing the procedures in the
calibration section of this manual. Do not attempt to
calibrate the converter module. There are no converter
module adjustments.

Parts Ordering

When corresponding with the Fisher sales office or
sales representative about this equipment, be sure to
mention the positioner serial number. When ordering
replacement parts, refer to the part number of each
required part as found in the following parts list.

Parts Kits

Key Description Part Number

Pneumatic Positioner Elastomers Kit

Contains keys 2, 15A, 17, 19, 22, 29,

30B, 31, 59, 69
nitrile R3710X00012
synthetic rubber R3710X00022

Electro-Pneumatic Converter Kit

Contains keys 76, 77, 79, 85, 88
nitrile R3722X00012
synthetic rubber R3722X00022

Parts

Key Description Part No. Qty

List

Testing the Type 3722 Converter Module

Check the operation of the converter module by instal­ling a pressure gauge in the instrument output port in
the converter housing.

1. Remove the pipe plug (key 86, figure 27) in the in­strument output port and connect a pressure gauge.
Provide supply pressure and a 4 to 20-mA dc input
signal.

2. Apply a 20 psig (1.4 bar) supply pressure. The in­strument output pressure at a 4-mA dc input signal
should be 2.3 to 3.5 psig (0.16 to 0.24 bar). The pres­sure output at a 20-mA dc input signal should be 14.0
to 15.5 psig (0.97 to 1.07 bar).

* Recommended spare part.

1. Also recommended as a spare part if metric fasteners are not available at the
installation site.

Positioner Common Parts (Figure 26)

1* Spool Valve Assy, SST/SST

2* O-ring, used between spool valve and

3

std capacity 22B7250X012 1

high capacity 22B7312X012 1
action block

nitrile 12B7253X012 3

synthetic rubber 12B7253X022 3

(1)

Screw (metric), slot-head/cross-recessed,

S18800 (18-8 SST)

Qty 4 req’d to attach action block to

positioner base plate

Qty 2 req’d to attach spool valve to

action block

Qty 4 req’d to attach input module to

positioner base plate 12B7254X012 10

31

Types 3710, 3720, 3722

42B7272 SHT 1 OF 3/DOC

42B7272 SHT 2 OF 3/DOC

42B7272 SHT 2 OF 3/DOC

Figure

26. T

ype 3710 Components and Subassemblies

32

Types 3710, 3720, 3722

42B7272 SHT 3 OF 3/DOC

Figure

26. T

ype 3710 Components and Subassemblies (Continued)

33

Types 3710, 3720, 3722

Key Description Part No. Qty

Note

To identify the span adjuster assy for 6 to 30 psig (0.4
to 2.0 bar) input range, red color coding appears on
the range spring.

4 Span adjuster assy, SST/plastic

3 to 15 psig (0.2 to 1.0 bar) (no color-coding) 22B7311X012 1
6 to 30 psig (0.4 to 2.0 bar) (color-coded red) 22B7311X022 1

5 Nameplate, positioner 12B4505X0A2 1
6 Screw, self-tapping, pan head, slotted,

for positioner nameplate

S18800 (18-8 SST) 1P426928982 2

7 Cover assy, includes screws (key 8) and

O-rings (key 7B), plastic/SST

nitrile O-rings 32B7264X012 1
synthetic rubber O-rings 32B7264X022 1

7B* O-ring, used to hold positioner cover screws

nitrile 12B7268X012 4
synthetic rubber 12B7268X022 4

(1)

8

Screw (metric), slot-head/cross-recessed,

S18800 (18-8 SST)

Qty 4 for indicator cover
Qty 4 for positioner cover (captive) 12B7267X012 8

9 Hex nut, S18800 (18-8 SST)

For indicator cover screws (key 8) 12B7269X012 4
10 Beacon indicator 12B2640X102 1
11 Extension feedback shaft, for use with

beacon indicator 32B7320X012 1

(1)

12

Retaining ring (e-clip) (metric), SST

Used to secure the indicator. Use inside the

positioner cover for the standard indicator

Use outside the positioner cover for the

beacon indicator 1F6252X0012 1

Note

Key 13, pointer, is used with key 15, indicator. Key 13,
pointer, fits over the molded Phillips slot in the center
of key 15 and rests in appropriate quadrant recess in
the surface of key 15. Key 15A, O-ring, fits over the
molded Phillips slot to retain key 13.

13 Pointer 22B7323X022 1
14 Indicator scale 32B7259X022 1

Note

Key 15, indicator, features a molded Phillips slot to
facilitate adjustment of the indicator during installation
of the positioner cover.

15 Indicator w/molded Phillips slot, plastic

w/nitrile O-ring (key 15A) 32B7306X022 1

w/synthetic rubber O-ring (key 15A) 32B7306X032 1

Key Description Part No. Qty

Note

Key 16, base assy, includes key 38, feedback shaft,
and key 17, flanged bearing (qty 2) only. Key 16 does
not include key 18, supply cover, key 19, O-ring, and
key 70, screw (qty 2).

16 Base assy, aluminum/SST 42B7304X012 1
17* Flanged bearing, nylon

Qty 2 for feedback shaft (key 38) 12B7324X012 2
18 Supply cover, S18800 (18-8 SST) 22B7277X012 1
19* O-ring, used under the supply

cover (key 18)

nitrile 13B9353X012 1
synthetic rubber 13B9353X022 1

(1)

20

Screw (metric), slot-head/cross-recessed,

S18800 (18-8 SST)

Qty 4 for diaphragm cover plate
Qty 2 for connecting summing beam

to input module 12B7279X012 6

21 Feedback arm assy, aluminum/SST

Includes needle bearing (key 25)

Needle bearing is pressed into

feedback arm 32B7293X012 1

22* Flanged bearing, nylon

For feedback pivot 12B7273X012 1

23* Cam roller (ball bearing, metric)

S18800 (18-8 SST)

Here, the bearing is used as the cam roller,

attached to the feedback arm assy (key 21)
by the shoulder screw (key 24) 12B7297X012 1

(1)

24

Shoulder screw (metric), S18800 (18-8 SST) 12B7298X012 1

25 Needle bearing, S18800 (18-8 SST)

Needle bearing is pressed into the feedback

arm (key 21). To install a new needle
bearing, the existing bearing must be
pressed out. Please consult your Fisher
sales office or representative 12B7271X012 1

(1)

26

Washer (metric), S18800 (18-8 SST) 12B7299X012 1

(1)

27

Retaining ring (e-clip) (metric)

S18800 (18-8 SST) 12B7300X012 1

28 Action block, A03600 (aluminum) 32B7261X012 1
29* Action block gasket

neoprene 32B7262X012 1

synthetic rubber 32B7262X022 1

30 Input module assy

Includes:

30A Input module housing 42B7281X012 1
30B* Input module diaphragm

nitrile 22B7282X012 1

synthetic rubber 22B7282X022 1
30C Diaphragm plate 12B7283X012 2
30D Diaphragm connector 12B7284X012 1

(1)

30E

Screw (metric), slot-head/cross-recessed,

For connecting summing beam to

diaphragm connector

30F

Screw (metric), pan head

S18800 (18-8 SST) 12B7279X012 1

(1)

This screw passes through the top

diaphragm plate, diaphragm, and
bottom diaphragm plate. Screw it
into the diaphragm conn. (key 30D) 13B6878X012 1

34

* Recommended spare part.

1. Also recommended as a spare if metric fasteners are not available at the
installation site.

Types 3710, 3720, 3722

Key Description Part No. Qty

30G Diaphragm cover 22B7286X012 1
30H Summing beam assy 22B7287X012 1

30K Summing beam flexure 22B7290X012 1
30L Flexure retainer 12B7291X012 2
30M Spring seat 23B8701X012 1

31* O-ring

For use between input module assy and

positioner base plate
nitrile 12B7292X012 1
synthetic rubber 12B7292X022 1

32 Zero adjustment pivot, S30300 (303 SST) 22B7301X012 1

(1)

33

Washer (metric), S18800 (18-8 SST)

For zero adjustment pivot 12B7317X012 1

(1)

34

Retaining ring (e-clip) (metric)

S18800 (18-8 SST)

For zero adjustment pivot 12B7318X012 1

Note

Key 35, zero adjuster, shows a quantity of 2. One is
used for the zero adjustment locknut and one is used
for the zero adjustment knob.

35 Zero adjuster, SST/plastic 22B7302X012 2
36* Cam, S18800 (18-8 SST) 32B7303X012 1

(1)

37

Cam locknut (hex/metric),

S18800 (18-8 SST) 12B7296X012 1

38 Feedback shaft (cam shaft),

S30300 (303 SST) 32B7305X012 1

(1)

39

Washer (metric), S18800 (18-8 SST)

For feedback shaft (cam shaft) (key 38) 12B7315X012 1

(1)

40

Retaining ring (e-clip) (metric)
S18800 (18-8 SST), for feedback shaft

(cam shaft) (key 38) 12B7316X012 1

41 Vent screen, S18800 (18-8 SST) 12B7321X012 1

Note

To attach a gauge or tire valve to the positioner or con­verter, use a pipe nipple (key 68) and a street tee (key

56).

53* Supply gauge, plastic case,

W/chrome-plated brass connection
(requires street tee, key 56)

0 to 30 psig/0 to 0.2 MPa/0 to 2 bar 11B4040X012 1

0 to 60 psig/0 to 0.4 MPa/0 to 4 bar 11B4040X022 1

0 to 160 psig/0 to 1.1 MPa/0 to 11 bar 11B4040X032 1

54* Instrument gauge, plastic case,

W/chrome-plated brass connection
(requires street tee, key 56)

0 to 30 psig/0 to 0.2 MPa/0 to 2 bar 11B4040X012 1

0 to 60 psig/0 to 0.4 MPa/0 to 4 bar 11B4040X022 1

55* Output gauge, plastic case

W/chrome-plated brass connection
(requires street tee, key 56)

0 to 30 psig/0 to 0.2 MPa/0 to 2 bar 11B4040X012 1

0 to 60 psig/0 to 0.4 MPa/0 to 4 bar 11B4040X022 1

0 to 160 psig/0 to 1.1 MPa/0 to 11 bar

(single action) 11B4040X032 1

0 to 160 psig/0 to 1.1 MPa/0 to 11 bar

(double action) 11B4040X032 2

Key Description Part No. Qty

56 Street tee, qty 1, required to attach each

gauge or tire valve to pipe bushing (key 68)

Steel, carbon steel, zn pl 1P312321992 1
SST, S31600 (316 SST) 1P506938982 1

57 Pipe plug, for single-acting positioners only

alloy steel, pl 1C333528992 1
SST 1A767535072 1

62 Tire valve

Single action 1H447099022 1
Double action 1H447099022 2

63 Dow Corning Comp 111 Lubricant

(not furnished with positioner)

64 Sealant, Zink-Plate No. 770

(2)

or equivalent

(3)

or equivalent

(not furnished with positioner)

65 Lubricant, 20W/50 Motor Oil or equivalent

(not furnished with positioner)

66

Dow Corning Magna-Lub G

(4)

or equivalent

(not furnished with positioner)

68 Pipe bushing, qty 1, required to attach each

pipe tee (key 56) to positioner connection

Steel, carbon steel, pl 1E253726232 1
SST, S31600 (316 SST) 1E2537K0012 1

69* Spacer, qty 1, required between the feedback

shaft (key 38) and the positioner base plate

plastic 13B8202X012 1

(1)

70

Screw (metric), slot-head/cross-recessed

Used to secure key 18, supply cover, to key 16,

base ass’y

S18800 (18-8 SST) 13B9626X012 2

Diagnostic Connections (Figure 28)

FlowScannert valve diagnostics system hook-up

Includes pipe tee, pipe nipple, pipe
bushings, connector body, and body
protector. If ordered for units with
gauges, a stem is also included. Also,
the part number provides correct
quantities of each item.

For Type 3710 Positioner

Single-action units

For units w/gauges

SST fittings 12B8054 X012
Brass fittings 12B8054 X022

For units w/o gauges

SST fittings 12B8054 X032
Brass fittings 12B8054 X042

Double-action units

For units w/gauges

SST fittings 12B8055 X012
Brass fittings 12B8055 X022

For units w/o gauges

SST fittings 12B8055 X032
Brass fittings 12B8055 X042

* Recommended spare part.

1. Also recommended as a spare part if metric fasteners are not available at the
installation site.

2. Mark owned by Dow Corning Corp.

3. Mark owned by Armite Laboratories.

4. Mark owned by Dow Corning Corp.

35

Types 3710, 3720, 3722

Figure

27. T

34B0694-A/DOC

Key Description Part No. Qty
For Type 3720 Positioner

Single-action units

For units w/gauges

SST fittings 13B8742 X012
Brass fittings 13B8742 X022

For units w/o gauges

SST fittings 13B8742 X032
Brass fittings 13B8742 X042

Double-action units

For units w/gauges

SST fittings 13B8743 X012
Brass fittings 13B8743 X022

For units w/o gauges

SST fittings 13B8743 X032
Brass fittings 13B8743 X042

36

ype 3722 Components and Subassemblies

Key Description Part No. Qty

Type 3722 Electro-Pneumatic Converter
(Figure 27)

71 Housing, aluminum

1/2-inch NPT conduit connection

standard 24B0625X012
explosion-proof 24B0626X012

M20 thread conduit connection 24B0627X012

72 Cap, aluminum

standard 31B2305X012
explosion-proof 21B2393X012

73 Screw, aluminum (not shown)

used to secure explosion-proof cap 11B8574X012

74 Cable gland, plastic

for M20 thread conduit connection 11B3870X012

75 Nozzle restriction

Aluminum/synthetic sapphire 13B7116X012

76* O-ring

used w/nozzle restriction, key 75

nitrile 1P420706992
synthetic rubber 1P4207X0032

* Recommended spare part.

Types 3710, 3720, 3722

Key Description Part No. Qty

77* O-ring

Qty 1 used w/nozzle restriction, key 75
Qty 1 used w/converter module, key 89

nitrile 1C8538X0022 2
78 Vent, plastic/stainless steel 11B8279X012
79* O-ring

80 Machine screw, stainless steel 1A9021X0012 2
81 Wire retaining screw, pl steel

82 Lubricant, Lubriplate

83 Sealant, Zink-Plate No. 770
84 Cap screw, hex socket, S18800 (18-8 SST)

85* O-ring

86 Pipe plug, hex head

87 Lubricant, Never-Seez Nickel Lubricant
88 Filter, stainless steel 11B5996X012

89 I/P converter module 33B7073X012
90 Nameplate, converter module 14B0227X0A2

91 Screw, self-tapping, pan head, slotted,

synthetic rubber 1C8538X0072 2

used with converter cap, key 72

nitrile 1H8762X0012

synthetic rubber 1H8762X0032

Used as a grounding screw
Qty 2: internal and external locations
includes square washer 16A2821X012 2

(not furnished with positioner) –––

(not furnished with positioner) –––
For attaching the converter to the

positioner base plate 14B0695X012 2
used between positioner base plate and converter

nitrile 11A8741X052 2
synthetic rubber 11A8741X032 2

steel 1D829328982
stainless steel 1D8293X0012

or equivalent (not furnished with positioner) –––

for positioner nameplate

S18800 (18-8 SST) 1P426928982 2

(5)

MAG-1 or equivalent

(3)

or equivalent

(6)

Positioner Mounting Parts (Figure 29)

Note

To mount the Type 3710 or 3720 positioner to an
existing actuator, replace the actuator cover plate with
a new plate which has the three positioner mounting
holes and the 5/8-inch purge option knockout plug.

Please contact your Fisher Controls sales office or
representative for any additional parts required for
controller mounting.

Actuator cover plate, aluminum

For 1051/1052 size 30
For 1061 size 30 22B8469X012 1
For 1051 size 60 22B8471X012 1
For 1052 size 60, 70 22B8471X012 1
For 1061 size 30, 40, 60 22B8471X012 1

(7)

, 40 22B8469X012 1

Key Description Part No. Qty

42 Tie bar, S18800 (18-8 SST)

For 1051/1052 size 33 and 1066 size 20,

use tie bar extension (key 44) instead
of the tie bar (key 42)

For 1032 sizes 45, 70, 185, 280, 425,

680, 1125, 1370, 2585, 4580, use the
coupling (key 60) and spacer (key 61)
instead of the tie bar (key 42).

For 1031 sizes 26 14B1489X012 1
For 1031 sizes 33, 45, 60, 80 12B8467X012 1
For 1051/1052 sizes 30(7), 40, 60 12B8467X012 1
For 1052 size 20 12B8464X012 1
For 1052 size 70 12B8467X012 1
For 1061 sizes 30, 40, 60, 68 12B8467X012 1
For 1061 sizes 80, 100 12B8473X012 1
For 1066 size 27 12B8480X012 1
For 1066 size 75 12B8485X012 1

43 Mounting plate, steel

For 1031 sizes 26, 33, 45, 60, 80 32B8487X012 1
For 1032 size 45 32B8463X012 1
For 1032 sizes 70, 185, 280 32B8495X012 1
For 1032 sizes 1125, 1370, 2585, 4580 33B0320X012 1
For 1052 size 20 32B8465X012 1
For 1051/1052 size 33 32B8463X012 1
For 1061 sizes 80, 100 32B8475X012 1
For 1066 size 20 32B8463X012 1
For 1066 size 27 32B8463X012 1
For 1066 size 75 32B8486X012 1

44 Tie bar extension, S18800 (18-8 SST)

For 1051/1052 size 33 12B8462X012 1
For 1066 size 20 12B8468X012 1

45 Cap screw, hex head, steel, pl

For attaching the mounting plate to
the actuator cover plate

For 1031 sizes 26, 33, 45, 60, 80 1A782024052 2
For 1032 size 45 1A407824052 4
For 1032 sizes 70, 185, 280 1C631224052 4
For 1032 sizes 425, 680 1D529824052 2
For 1032 sizes 1125, 1370 1A3444K0022 2
For 1032 sizes 2585, 4580 1A485724052 2
For 1052 size 20 1A344924052 4
For 1051/1052 size 33 1C5958X0022 2
For 1066 size 20 1C5958X0022 2
For 1066 size 27 1A353124052 2
For 1066 size 75 1A582324052 2

46 Cap screw, hex socket, S18800 (18-8 SST)

For attaching the positioner base
plate to the mounting plate or
actuator cover plate

For 1031 sizes 26, 33, 45, 60, 80 1J591438992 3
For 1032 sizes 45, 70, 185, 280,

425, 680 1L481238992 3
For 1032 sizes 1125, 1370, 2585, 4580 1J591438992 3
For 1051/1052 sizes 30(7), 40, 60;

1052 size 70; 1061 sizes 30, 40,

60, 68 10B1246X042 3
For 1051/1052 size 33; 1052 size 20;

1061 sizes 80, 100; and

1066 sizes 20, 75 1J591438992 3
For 1066 size 27 12B8481X012 3
For 1066 size 75 1J591438992 3

* Recommended spare part.

5. Mark owned by Armite Laboratories.

6. Mark owned by Dow Corning Corp.

7. The size 30 actuator is no longer manufactured by Fisher Controls. The type 3710
positioner is available for field installation on existing size 30 actuators.

37

Types 3710, 3720, 3722

13B8743-A
B2414/IL

12B8055-A
B2385/IL

38

Figure

28. Diagnostic Connections

Types 3710, 3720, 3722

42B8478-A/DOC

Figure

29. Positioner Mountings

Key Description Part No. Qty

47 Machine screw, self-tapping, S18800 (18-8 SST)

For attaching the tie bar or tie
bar extension to the actuator hub

For 1031 sizes 26, 33, 45, 60, 80 15A7843X022 2
For 1051/1052 sizes 30

1052 size 70; 1061 sizes 30, 40,

60, 68 15A7843X022 2
For 1052 size 20 1B9925X0012 2
For 1051/1052 size 33 1H332538992 2
For 1061, sizes 80, 100 15A7843X022 2
For 1066 sizes 20, 27 1V7309X0012 2
For 1066 size 75 1A8176X0012 2

58 Purge tube, S18800 (18-8 SST)

For 1051/1052 sizes 30

1052 size 70; 1061 sizes 30, 40,
60, 68 12B7322X012 1

59* O-ring, purge tube, nitrile F1367806562 2
60 Coupling, S18800 (18-8 SST)

For 1031 sizes 26, 33, 45, 60, 80 12B8482X012 1
For 1031 sizes 60, 80 12B8474X012 1
For 1032 sizes 45, 70, 185, 280,

425, 680 12B8494X012 1

For 1032 sizes 1125, 1370, 2585, 4580 12B8498X012 1
For 1061 sizes 80, 100 12B8474X012 1
For 1066 size 27 12B8482X012 1

61 Spacer, steel

For 1031 sizes 26, 33, 45, 60, 80 17A8301X012 2
For 1032 sizes 45, 70, 185, 280, 425, 680 1N416224092 3
For 1032 sizes 1125, 1370 12B8497X012 2
For 1032 sizes 2585, 4580 12B8499X012 2
For 1066 size 27 1N822924092 3

(7)

, 40, 60;

(7)

, 40, 60;

Key Description Part No. Qty

67 Indicator, steel

For 1031 size 26 12B8493X012 1
For 1031 size 33 12B8492X012 1
For 1031 size 45 12B8491X012 1
For 1031 size 60 12B8488X012 1
For 1031 size 80 12B8489X012 1

For mounting the 67AFR on the Type 1032
actuator

Cap screw 1K747624052 2
Lock washer 1C225728982 2
Hex nut 1E944024112 2

Fittings

Note

Contact your Fisher Controls sales of­fice or representative for descriptions of
fittings including materials of construc­tion. Specify quantity of fittings re­quired.

50 Elbow
51 Connector
52 Swivel

* Recommended spare part.

7. The size 30 actuator is no longer manufactured by Fisher Controls. The Type 3710
positioner is available for field installation on existing size 30 actuators.

39

Types 3710, 3720, 3722

42B8466-A/DOC

42B8484-A/DOC

40

Figure

29. Positioner Mountings (Continued)

32B8490-A/DOC

Types 3710, 3720, 3722

33B0322-B/DOC

33B0321-B/DOC

Figure

29. Positioner Mountings (Continued)

41

Types 3710, 3720, 3722

Errata Sheet for

August 1994

Types 3710

1. On page 6 of the instruction manual, near the
heading Mounting the Positioner, write a note that
says, “Also see errata sheet dated August 1994”.

2. On page 37 of the instruction manual, near the
heading Positioner Mounting Parts, write a note that
says, “Also see errata sheet dated August 1994”.

Installing

the T

, 3720 P

neumati

c P

ype 3710 or 3720

ositioner

For

m 5

Pneumatic Positioner on Size 25 or
50 Type 585 and 585R Actuators

Refer to figures 1, 2, and 3 in this errata sheet for key
number locations unless noted otherwise.

1. An actuator stem bracket is supplied with the posi­tioner. Assemble the various positioner feedback parts
to the stem bracket as follows:

a. Refer to figure 2. Install the roller bearing (key

101) on the drive stud (key 95) and secure with the
E-ring (key 102).

b. Refer to figure 3. Attach the drive stud (with roll­er bearing) to the drive stud bracket (key 98) with
1/4-inch hex nut (key 96), lock washer (key 100),
and flat washer (key 103). Place the flat washer
between the lock washer and the hex nut. The
washers and hex nut should all be on the same
side of the drive stud bracket as shown in figure 3.
The flat washer may be moved to the other side of
the drive stud (between the drive stud and the drive
stud bracket) if extra space is required to position
the roller bearing near the center of the feedback
lever. Leave the hex nut loose for later adjustment.

c. Attach the drive stud bracket (with drive stud) to
the actuator stem bracket using two cap screws
(key 99), two lock washers (key 100), and two hex
nuts (key 96). Leave the hex nuts loose for later
adjustment.

2. Stroke the actuator from the top stop to the bottom
stop, and record the travel.

In steps 3 through 6, refer to the actuator instruction
manual for key number locations unless noted other­wise.

s a

nd Type 372

300

, July 1

3. Loosen eight screws, and remove the front and
back yoke covers (keys 18 and 20).

4. Loosen the two cap screws in the stem connector
assembly (key 15) and remove the stem connector.
Separate the actuator piston stem (key 12) from the
valve plug stem.

5. Loosen the stem bracket retainer (key 14) and let it
slide down over the valve plug stem. Remove the
stem bracket assembly (key 13).

6. Install the stem bracket assembly (with drive stud
and drive stud bracket) on the actuator stem. Align the
stem bracket assembly so that it will be parallel with
the back yoke cover. Install the stem bracket retainer
and tighten to 50 lbfSft (68 NSm). If the actuator was
removed from the valve, install the actuator on the
valve. Do not attach the stem connector at this time.

7. Attach the mounting bearing (key 97) to the mount­ing plate (key 43) with three hex socket cap screws
(key 93).

8. Refer to the actuator instruction manual. Loosen
the four screws, and remove the actuator blanking
plate.

9. Attach the positioner mounting plate to the actuator
yoke as shown in figure 4 with four spacers (keys 61),
four cap screws (key 45) and lock washers (key 92).

10. Loosen the four captive cover screws and remove
the positioner cover.

11. Loosen the cam locknut (key 37, figure 26).

12. Attach the positioner to the mounting plate with
three hex socket cap screws (key 46). Make sure that
the positioner feedback shaft (key 38, figure 26) ro­tates freely and is not binding with the mounting bear­ing, adjust if necessary.

13. Attach the feedback lever (key 94) to the end of
the feedback shaft with the two hex socket cap screws

2 C

onverte

r I

nstructio

993

Before performing the next step,
position the valve plug stem at the lower
end of its travel. Position the actuator
stem at the upper travel stop. Check for
sufficient clearance between the
actuator stem and the valve stem to
allow removing the stem bracket
assembly. If there is in sufficient
clearance, remove the actuator from the
valve.

Note

n M

anual

42

Types 3710, 3720, 3722

Figure 1. Typical T

(key 93). The markings on the feedback lever should
be visible when looking toward the back of the posi­tioner. Make sure the roller bearing (key 101) on the
drive stud engages the slot in the feedback lever.

ype 3710 Positioner Mounted on a T

WARNING

An unexpected change in actuator sup­ply pressure while performing the fol­lowing steps could result in personal
injury. Use lockout procedures to en­sure a stable air supply.

14. Perform the Actuator Mounting procedure steps 2
through 8 in the actuator instruction manual to recon­nect the actuator stem and valve stem.

15. Make sure the cam locknut (key 37, figure 26) is
loose, then stroke the valve/actuator to mid-travel. Ad-

ype 585 Actuator

just the drive stud location vertically so that the feed­back lever is perpendicular to the stem. Tighten the
hex nut attached to the drive stud.

16. Refer to figure 5. Adjust the position of the drive
stud bracket so that the center of the roller bearing
aligns with the appropriate travel mark on the feed­back lever.

17. Tighten the cap screws to secure the drive stud
bracket to the stem bracket. If necessary, readjust the
drive stud position to keep the feedback lever perpen­dicular to the stem.

18. Make the output, supply, instrument, and vent
connections as described in the Connection section.
Calibrate the positioner by performing the procedures
in the Calibration section.

19. Replace the actuator front and back yoke covers.
Discard the actuator blanking plate and four screws.

43

Types 3710, 3720, 3722

Figure 2. Drive Stud and Roller Bearing Assembly

Figure 4. Mounting Plate Positioned on Actuator

Figure 3. Drive Stud Bracket with Drive Stud

and Roller Bearing Assembly

Parts

List

Mounting Parts for Mounting
Positioner on Type 585 and
585R Actuators

See figures 1, 2, and 3 in this errata sheet for key number unless noted
otherwise.

Key Description Part Number

38 Feedback Shaft (see instruction manual figure 26) 34B3927 X012
43 Mounting Plate 34B3929 X012
45 Cap Screw
46 Cap Screw
61 Spacer
92 Lock washer
93 Cap Screw

1B7877 24052

1J5914 38992

1F9067 24092
1C2257 28982
1R4500 28982

Figure 5. Positioning Drive Stud in Feedback Lever

Key Description Part Number

94 Feedback Lever 24B4168 X012
95 Drive Stud 14B4166 X012
96 Hex Nut
97 Mounting Bearing 14B4329 X012
98 Drive Stud Bracket 24B4627 X012
99 Cap Screw
100 Lock washer
101 Roller Bearing 14B5617 X012
102 E-RIng11A7309 X012
103 Washer

Pipe Nipple, for mounting Type 67 Filter Regulator

1A3457 24122

1E8220 38992

1L3239 28982

1A4988 28982
1B2927 38322

44

Types 3710, 3720, 3722

December 1994, Form 5362

Type 372

Loop Schematics

This document includes loop schematics required for
wiring of intrinsically safe installations. If you have any
questions, contact your Fisher Controls sales repre­sentative or sales office.

CSA Schematics

2 E

lectro-Pneumati

c C

onverter

24B0238-A/DOC

45

Types 3710, 3720, 3722

FM Schematics

24B0239-A/DOC

Fisher, Fisher-Rosemount, and Managing The Process Better are marks owned by Fisher Controls International, Inc. or Fisher-Rosemount Systems, Inc.
All other marks are the property of their respective owners.

EFisher Controls International, Inc. 1991, 1993; All Rights Reserved

                        
                             

For information, contact Fisher Controls:

Marshalltown, Iowa 50158 USA
Cernay 68700 France
Sao Paulo 05424 Brazil
Singapore 128461

46

Printed in U.S.A.