Initial Adjustments7.
Signal Range Codes8.
Frequency Response8.
Adjustment Procedures8.
Changing Positioner Action12.
Split Range Operation13.
Initial Range Spring Extension Procedure
This manual provides installation, operation, adjustment, maintenance, and parts ordering information for
the 3570 Series pneumatic valve positioners. The various product types within this series are described later
in this manual. Please refer to figure 1 for a typical
mounting of a Type 3570 positioner. Refer to separate
instruction manuals for information concerning the actuator, valve, and accessories.
Note
Only personnel qualified through train-
ing or experience should install, oper-
ate, and maintain these positioners. If
there are any questions concerning
these instructions, contact your Fisher
sales representative or sales office be-
fore proceeding.
Description
The 3570 Series pneumatic valve positioners are used
with control valve assemblies to provide an accurate
valve stem position that is proportional to the input
signal received from a control device. The input signal
range can be 3 to 15 psig (0.2 to 1.0 bar), 6 to 30 psig
(0.4 to 2.0 bar), or another pneumatic input signal
range, as required.
These posit ioner s are normally used with pneumatic piston actuators . However, product types within the 3570
Series can be used with pneumatic, long-stroke, cylinder
actuators or with pneumatic diaphragm actuators .
Valve Positioner Type Numbers
Type 3570 — Pneumatic valve positioner with two
relays for use with Fisher 470 and 480 Series pneumatic piston actuators. See figure 2. The positioner
includes three pressure gauges for input signal, for
relay output pressure to the top of the actuator cylinder, and for relay output pressure to the bottom (piston
underside) of the actuator cylinder.
The Type 3570 positioner is mounted on the top of the
actuator cylinder. The actuator stem position feedback
is provided through extension of the range spring attached to the actuator piston rod.
Type 3570C — Pneumatic valve positioner with automotive tire valves instead of pressure gauges. Tire
valves can be used for clip-on test pressure gauges.
The relay nozzles are locked in place with locknuts to
resist unwanted nozzle movement due to vibration.
Type 3570P — Pneumatic valve positioner with two
relays for use with Fisher 490 Series pneumatic piston
actuators. The positioner includes three pressure
gauges for input signal, for relay output pressure to
the top of the actuator cylinder, and for relay output
pressure to the bottom (piston underside) of the actuator cylinder.
The Type 3570P positioner is mounted alongside the
actuator cylinder. Actuator stem position feedback is
provided from the actuator-valve stem connector
through a cable and spool assembly.
Type 3570PC — Pneumatic valve positioner with automotive tire valves instead of pressure gauges. Tire
valves can be used for clip-on test pressure gauges.
The relay nozzles are locked in place with locknuts to
resist unwanted nozzle movement due to vibration.
Type 3571 — Pneumatic valve positioner with two
relays for use with long-stroke cylinder actuators. The
positioner includes three pressure gauges for input
signal, for relay output pressure to the top of the actuator cylinder, and for relay output pressure to the
bottom (piston underside) of the actuator cylinder.
The Type 3571 positioner is bracket-mounted to the
side of the actuator. Actuator stem position feedback
is provided through a wire from the actuator-valve
stem connector.
Type 3572 — Pneumatic valve positioner with one
relay. The Type 3572 positioner is normally used on
the Fisher Type 472 pneumatic piston actuator
mounted on valve bodies having push-down-to-open
(PDTO) action. The positioner includes two pressure
gauges. The pressure gauges monitor input signal
pressure and relay output pressure to the top of the
actuator cylinder.
The Type 3572 positioner is mounted on the top of the
actuator cy linder. Actuator st em position feedback is provided through an extension of the actuator piston rod.
Type 3573 — Pneumatic valve positioner that is similar
to Type 3572 positioner with the relay output pressure
piped to the bottom (piston underside) of the actuator
cylinder. The Type 3573 positioner is normally used on
the Fisher Type 473 pneumatic pist on actuator with
valve bodies hav ing push-down-to-close (P DT C) action.
Type 3576 — Pneumatic valve positioner with one relay
for use on direct-acting pneumatic diaphragm actuators
that requir e high operating pressures. The Type 3576
positioner includes two pressure gauges. The pressure
gauges monitor input signal pressure and relay output
pressure to the top of the act uator diaphragm.
2
Table 1. Specifications
PRESSURE
ST
ANDARDGAUGE
POSITIONER
3570 Series
Available Configurations
See the positioner type number descriptions given
above.
Input Signal
(1)
Standard Ranges: 3 to 15 psig (0.2 to 1.0 bar) or
6 to 30 psig (0.4 to 2.0 bar)
Optional Ranges: As desired, within the limits of
the bellows
Split Ranges: Use one-half of either standard
range when two control valves are operated by one
output signal form a single control device
Output Signal
(1)
Type: Pneumatic pressure as required to maintain
the correct valve stem position and seat load
Action: Field-reversible between direct and reverse
Resolution
(1)(2)
0.2% of instrument pressure span
Repeatability
(1)(2)
0.3% of total stroke or instrument pressure span
Frequency Response
(1)(2)
See figure 5
Pressure Indications
Type 3570C and 3570CP Positioners: Tire valves
accept standard pressure gauge chucks (gauges
not supplied)
20 scfh (0.54 normal m3/h) with 100 psig (6.9 bar)
supply pressure
Operative Ambient Temperature Limits
(1)(2)
With Nitrite O-Rings and Diaphragms: –30 to
160°F (–34 to 71°C)
With Fluoroelastomer O-Rings and Polyacrylate
Diaphragms (Optional): 0 to 220°F (–18 to 104°C)
Options
Type SS-52 clip-on chuck (with or without gauge)
for Type 3570C positioners; restrictor (high-frequency filter for bellows)
Pressure Connections
Vent: 3/8-inch NPT
All others: 1/4-inch NPT
1. These terms are defined in ISA Standard S51.1:1979.
2. For a Type 3570 or 3570C positioner mounted on a Type 470 or 480 actuator. Values do not apply to other constructions or actuator-valve combinations.
3. Scfh at 60°F, 14.7 psia (m3/h at 0°C, 1.01325 bar, absolute).
Table 2. Pressure Indications
NUMBER OF
PRESSURE
MONITORED
Positioner
input signal
pressure
Cylinder
(relay output)
pressure
1. For gauges marked in other units and ranges, consult your Fisher sales
representative or sales office.
GAUGES SUPPLIED
Two-Relay
Positioner
One-Relay
Positioner
11
210-160 psi/0-1.1 MPa/0-1
ST
ANDARD GAUGE
RANGE
0-30 psi/0-0.2 MPa/0-2 bar or
0-60 psi/0-0.4 Mpa/0-4 bar
(1)
1 bar
Approximate Weight
6 pounds (2.7 kg) without optional mounting bracket
or actuator/valve assembly
Table
3. Action Under Normal Operating Conditions
POSITIONER
ACTION
Direct-acting
Reverse-acting
1. Supply pressure is routed through relays to piston.
Increasing input signal
pressure to bellows
Decreasing input signal
pressure to bellows
DESIRED PISTON MOTION
DownUp
Type 3577 — Pneumatic valve positioner that is simi-
lar to Type 3576 positioner with the relay output pressure piped to the underside of the actuator diaphragm
on reverse-acting pneumatic diaphragm actuators.
The Type 3576 positioner is bracket-mounted to the
actuator yoke. Actuator stem position feedback is provided through a wire from the actuator-valve stem connector.
Specifications
Specifications for the 3570 Series positioners are
listed in table 1.
(1)
Decreasing input signal
pressure to bellows
Increasing input signal
pressure to bellows
3
3570 Series
Installation,
Mounting, and
Connections
Installation
The positioner is usually mounted on the actuator at
the Fisher Controls’ factory. However, if the positioner
and actuator are ordered separately, it is necessary to
mount the positioner on the actuator. Before mounting
the positioner, be certain the O-ring (key 33, figure 11)
is in place in the cylinder (top connection) in the base
of the positioner.
For appropriate actuator/positioner combinations, refer
to the positioner type number descriptions given earlier in this instruction manual.
D For Type 3570, 3570C, 3572, and 3573 posi-
tioners, mount the positioner with two cap screws
(key 32, figure 11). If the range and bias springs are
not installed in the positioner, refer to the range spring
and bias spring procedures in the Maintenance section.
Insert the threaded end of the spring retainer (key 19,
figure 3) into the center of the range spring (see figure
3). Then, insert a screwdriver into the center of the
range spring and extend the spring until the spring retainer can be screwed into the top of the actuator piston rod extension. Tighten the spring retainer into the
top of the actuator piston rod extension. If the range
spring and/or bias spring is not installed in the positioner, refer to the procedures for either spring in the
Maintenance section.
To support diagnostic testing of the control valve assembly, the connectors, piping, and other hardware
can be installed between the 3570 Series positioner
and the actuator. A typical connector installation is
shown in figure 4. For connectors, please refer to the
FlowScannert Diagnostic Connection kit listing in the
parts list.
The hardware used includes 3/4-inch NPT pipe nipple,
pipe tee, and pipe bushings with a 1/8-inch NPT pipe
bushing for the connector. The connector consists of
1/8-inch NPT body and body protector (see figure 4).
1. Before assembling the pipe nipple, pipe tee, pipe
bushings, actuator piping, and connector body, apply
sealant to all threads.
2. Position the pipe tee, connector body, and body
protector for easy access when doing diagnostic testing.
Connections
Piping Sizes
All pressure connections on the 3570 Series positioners are 1/4-inch NPT (female). Use 3/8-inch pipe or
tubing for supply, cylinder (bottom connection), and
instrument (input signal) connections. For the remote
vent pipe, if one is required, use 3/4-inch (19 mm)
(minimum inside diameter) pipe for runs up to 20 feet
(6.09 meters). For vent piping runs from 20 to 100 feet
(6.09 to 30.5 meters), use 1-inch (25.4 mm) (minimum
inside diameter) pipe. Refer to figure 2 for the locations and sizes of connections.
D For Type 3570P and 3570PC positioners, at-
tach the positioner extension and positioner to the cylinder mounting plate with the two cap screws (key
100, figure 13). Make the required pressure connections as described in the following procedure. Go to
the initial range spring extension procedures for Type
3570P and 3570PC positioners.
D For Type 3571, 3576, and 3577 positioners,
insert two cap screws through the holes in the mounting bracket (key 55, figure 14) to attach the positioner
to the actuator mounting boss. Attach the hex drive
stud to the actuator-valve stem connection. Attach the
end bearing (key 56E, figure 14) to the hex drive stud.
Diagnostic Test Connectors (Optional)
Diagnostic test connectors are available from the factory, when the unit is ordered, or they can be installed
on an existing control valve assembly in the field.
These connectors are especially useful for ‘‘quick’’
connections when using the FlowScannert. The
FlowScannert is a portable, microprocessor-based
diagnostic and calibration system specifically designed
for use with pneumatically-operated control valves.
Vent
WARNING
If a flammable, toxic, corrosive, or reactive gas is to be used as the supply
pressure medium, personal injury or
property damage could result from fire
or explosion of accumulated gas or
from contact with toxic, corrosive, or
reactive gas. The positioner/actuator assembly does not form a gas-tight seal,
and when the assembly is enclosed, a
remote vent line, adequate ventilation,
and necessary safety measures should
be used. A remote vent pipe alone cannot be relied upon to remove all hazardous gas. 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.
4
FlowScanner is a mark owned by Fisher Controls International, Inc.
3570 Series
RANGE SPRING
(SPAN ADJUSTMENT)
CYLINDER
BOTTOM
PRESSURE
INSTRUMENT
PRESSURE
VENT CONNECTION
3/8-INCH NPT
BIAS SPRING SEAT
BIAS SPRING SEAT
(ZERO ADJUSTMENT)
(ZERO ADJUSTMENT)
W4025*/IL
NOTES:
1
ON SOME CONSTRUCTIONS, TWO NOZZLES AND ADJUSTMENTS ARE REQUIRED.
The connection marked VENT (see figure 2) should be
left open if the actuator is installed in the vertical position. However, the vent must be protected against the
entrance of any foreign material that could plug it.
Check the vent periodically to be certain it is not
plugged.
If the actuator is mounted in other than the vertical
position, be sure there is a vent and drain at the lowest point of the positioner. To do this, remove the pipe
plug (key 36, figure 10) from the cover. Then, position
the cover in such a way that the hole in the cover is at
the lowest point. Plug the vent connection because the
positioner is now vented through the cover.
influences can have on pneumatic
equipment, 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
40 microns in diameter should suffice
for most applications. Use of suitable
filtration equipment and the
establishment of a maintenance cycle to
monitor its operation is recommended.
WARNING
To avoid personal injury or property
damage resulting from the sudden release of pressure, do not install the
valve assembly where service conditions could exceed the limits given in
this manual or on the appropriate nameplates. Use pressure-relieving devices
as required by government or accepted
industry codes and good engineering
practices.
CAUTION
Note
A remote vent is not possible with Type
3570P, 3570PC, 3571, 3576, and 3577 po-
sitioners.
If a remote vent is required, the vent line must be as
short as possible with a minimum number of bends or
elbows. Vent line piping should have a minimum inside
diameter of 3/4 inches (19 mm) for runs up to 20 feet
(6.09 meters) and a minimum inside diameter of 1-inch
(25.4 mm) for runs from 20 to 100 feet (6.09 to 30.5
meters).
Supply Pressure Connections
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
instrument air quality standards
describe acceptable dirt, oil, and
moisture content. Due to the variability
in nature of the problems these
If the supply pressure medium is corrosive, make sure the tubing and instrument components that contact the corrosive medium are of suitable corrosionresistant material. The use of unsuitable
materials might result in personal injury
or property damage due to the uncontrolled release of the corrosive media.
The connection marked SUPPLY (see figure 2) must
be provided with clean, dry air or a non-corrosive gas.
Install a 40-micron filter and suitable equipment to dry
the supply medium. Establish a maintenance cycle to
ensure that the regulator and filter are working
correctly.
The maximum allowable supply pressure to prevent
damage to the components of the positioner, actuator,
and valve is normally stamped on the actuator nameplate. Use a suitable supply pressure regulator to reduce the supply pressure source to the value stamped
on the nameplate.
If this maximum supply pressure value is not available,
use a supply pressure that does not exceed any of the
following:
D The maximum supply pressure for the positioner
as shown in table 1.
6
3570 Series
D The maximum pressure rating of the actuator,
from the appropriate actuator instruction manual.
D The maximum allowable valve plug stem load for
the specific valve body assembly being used. Contact
your Fisher sales representative or sales office for
valve plug stem load information, if required.
D For diaphragm actuators, refer to the actuator
instruction manual for the recommended supply pressure and use the larger value of the range listed.
The recommended supply pressure for use with piston
actuators is the highest available supply pressure between 50 psig (3.4 bar) and the maximum limit determined by the actuator and positioner specifications.
Selecting the highest pressure within the limits will minimize load error and will maximize stroking speed and
thrust. For the lowest supply pressure that will assure
satisfactory performance, the factors of valve plug unbalance force, valve plug seating force, and frictional force
must be considered in the following relat ionship:
(Frictional
+
force,
kg)
]
+ 0.7 bar
Supply
pressure, = 98
bar
unbalance,
[
(Valve
kg)
(Area of the actuator piston,
(Seating
+
force,
kg)
in square mm)
3570P, 3570PC, 3571, 3576, and 3577 positioners, a
mounting bracket (key 55, figure 13) is required. This
mounting bracket connects to the bottom of the base.
An O-ring (key 33, figure 10) is placed between the
base and mounting bracket. This mounting bracket
provides a 1/4-inch NPT connection for the positioner
output. This connection is made at the factory if the
positioner is ordered mounted to the actuator or if the
mounting bracket is installed.
Instrument Connection
The connection marked INSTRUMENT (see figure 2)
connects to the output signal connection of the control
device. The positioner operates only on a pneumatic
input signal; the input signal range is marked on the
nameplate (key 23, figure 10). The maximum allowable input signal for positioners with standard or optional bellows is in table 1 (bellows pressure rating).
The instrument connection is made at the factory
when a complete control valve assembly with a valvemounted control device is ordered. Otherwise, make
field connections to the positioner from an appropriate
control device. Refer to table 1 and the nameplate for
input signal pressure ranges.
Operating Information
or
(Valve
Supply
pressure, =
psig
Consult your Fisher sales office or sales representative for the appropriate values for specific actuators,
valves, and service conditions. The 10 psig (0.7 bar) is
added to the equation to account for an approximate
10 psi (0.7 bar) differential pressure loss in the positioner. For spring-return piston actuators, the pressure
required to compress the actuator spring completely
must also be considered.
unbalance,
[
pounds)
(Area of the actuator piston,
(Seating
+
force,
pounds)
in square inches)
(Frictional
+
pounds)
force,
]
+ 10 psig
Cylinder Connections
1. The connect ion mark ed CYLI NDER (see figure 2) is
connected at the fac t ory to the lower part of the cylinder
(bottom) or to the lower diaphragm casing if the
positioner is used with a pneumatic diaphragm actuator.
2. The cylinder top connection is a pressure passage
located in the bottom of the positioner base (key 1,
figure 10). On Type 3570 and 3570C positioners, an
O-ring (key 33, figure 10) is used between the bottom
of the positioner and the top of the actuator. On Type
Initial Adjustments
Normally, no adjustments are necessary upon initial
installation. The positioner is set at the factory for the
travel, input signal range, and action specified in the
order. Adjustment is necessary when operating
conditions are changed, when the unit has been
dismantled and reassembled, or when the control
valve travel does not correspond to the desired input
signal range. If the operating conditions have not
changed but the positioner requires adjustment, refer
to the adjustment procedures in this section. If the
operating conditions have changed, first, refer to the
signal range code descriptions, then, refer to the
adjustment procedures.
Signal Range Codes
The range spring and the bias spring are matched to a
specific input signal range and length of travel. Also,
the spring retainer length is matched to the application
on the Type 3570, 3570C, 3572, and 3573 positioners.
Refer to figure 3 for location of parts.
The signal range codes in table 4 are based on the
following applications:
D Codes for valve travels up to and including
2 inches (50 mm) are used for actuators that have a
7
3570 Series
2-inch (50 mm) maximum travel. If the actuator maximum travel is greater than 2 inches (50 mm), an additional retainer spacer (key 235, see figure 3) is required. Refer to the parts list for the additional spring
retainer spacer (key 235) part number.
D Codes for valve travels greater than 2 inches
(50 mm), up to and including 4-1/8 inches
(105 mm), are used for actuators that have a
4-1/8 inch (105 mm) maximum travel, except the
Types 480-12 or 480-15 Size 20 actuators which have
a 2-1/8 inch (54 mm) maximum travel. If the actuator
maximum travel is greater than 4-1/8 inches (105
mm), two an additional retainer spacer are required.
Refer to the parts list for the additional spring retainer
spacer (key 235) part numbers.
D Codes for valve travels great er than 4-1/ 8 inch-
es (105 mm), up to an d in cl u di n g 8-1/ 8 in ch es (206
mm), are for actuators that have a 8-1/8 inch (206 mm)
maximum travel. If the valve travel is 4-1/8 inches (105
mm) or les s , two additional spring retainer spac er s are
required. Refer to the parts list for the additional spring
retainer spacer (k ey 235) part numbers.
If the input signal range and travel do not match any of
the selections in table 4, consult your Fisher sales office or sales representative for information. To change
the springs, refer to the range and bias spring procedures in the Maintenance section.
From table 4, select the signal range that matches
your application. Find the travel length for the application under the signal range selected, then use the
code (from the direct or reverse column) that matches
the direct or reverse operation of the positioner.
The first number in the code is used to identify the
range spring, the letter in the code is used to identify
the bias spring, and the second number (after the letter) is used to identify the spring retainer. For example, from table 4, for a signal range of 0 to 15 psig
(0 to 1.0 bar), an actuator travel of 9/16-inch (14.3
mm), and direct action, the signal range code from
table 4 is 6G3. The ‘‘6’’ indicates the range spring. The
‘‘G’’ indicates the bias spring. The ‘‘3’’ indicates the
spring retainer.
extension type spring to a compression type spring, it
is necessary to add the bias spring seat (key 8). Refer
to the appropriate procedures in the Maintenance section of this manual.
In some cases, it is necessary to add an additional
spring retainer spacer or change from the standard
bellows to the optional high pressure bellows. Table 4
footnotes indicate the use of an additional spring retainer spacer or high pressure bellows.
Use the code from table 4 while referring to tables 5,
6, and 7 to determine the part numbers for the range
spring, bias spring, and spring retainer. Unless otherwise specified, use the standard bellows. Also, no
spring retainer spacer is required unless the spacer is
specified in the footnotes of table 4.
Frequency Response
Figure 5 shows how a Type 3570 or Type 3570C positioner with Type 470 or Type 480 actuator responds
when the input signal pressure is cycled at a small amplitude (3 to 5 percent), and at an increasing frequency. Assume the cycling input signal and the movement
of the actuator rod are represented by sine waves. As
the actuator rod is forced to move faster, its motion
begins to fall behind the input signal in both time
(shown as phase lag) and amplitude (shown as
normalized gain).
Adjustment Procedures
Refer to figure 3. The 3570 Series positioners have
three adjustments:
D The bias spring. It is the zero adjustment which
determines the starting point of the valve plug travel.
D The range spring. It is the span adjustment
which determines the full valve plug travel for a given
input signal range.
D The relay nozzle adjustment. This adjustment
determines the steady- stat e positioner output pressur e.
Note
It is necessary to add the bias spring
seat (key 8) to a unit when changing
from an extension type spring (key 9) to
a compression type spring (key 48).
When planning to change the bias spring in an existing
unit, inspect the unit first to determine if the current
bias spring is an extension type spring (key 9) or a
compression type spring (key 48). To change from an
8
To illustrate the use of the various adjustments, assume that the positioner has been repaired or has become completely out of adjustment. Assume also that
the input signal range is 3 to 15 psig (0.2 to 1 bar).
Proceed as follows:
1. Make sure the input signal range and the valve
travel stamped on the nameplate agree with the present operating conditions.
2. Loosen the four thumb screws on the underside of
the positioner base and remove the cover.
1. Use spring retainer spacer 1J8038 46172; for additional information, see table 7.
2. Use spring retainer spacer 1J2233 46172; for additional information, see table 7.
3. Use spring retainer spacer 1J8039 46172; for additional information, see table 7.
4. Use with high pressure bellows and spring retainer spacer 1J8039 46172; for additional
information, see table 7.
5. Use with high pressure bellows.
6.4
11.1
12.7
19
25.4
26.2
39.7
48.3
50.8
17H4
1
10A2
10A2
11G4
2G4
2G4
2G5
5G5
5G5
12G13
12C8
12G7
12G13
(5)
(2)
(8)
A4
17H4
1
10H2
10D2
11H4
2D4
2H4
2D5
5D5
5D5
12H13
12C8
12D7
12D13
3. Provide a means for varying the input signal pressure from zero to 1 or 2 psig (0.07 or 0.14 bar) above
the higher value of the input signal range (see table 1).
Provide an accurate means of measuring the input
signal pressure. Check the accuracy of the positioner
instrument pressure gauge (see figure 2). The gauge
accuracy is±0.6 psig (±0.04 bar) on a 0 to 30 psig (0 to
2 bar) gauge, and ±1.2 psig (±0.08 bar) on a 0 to
60 psig (0 to 2 bar) gauge. This accuracy is measured
at the mid-point of the full range of the scale.
2-1/457.112G112D1
2.358.412G312C3
H4
2-3/8
2-5/8
2-3/4
3-1/8
3-1/4
3-5/16
3-3/8
3-1/2
3-9/16
3-21/32
4-1/8
5-1/4
5-5/8
6-1/2
60.3
-
3
(5)
(4)
6
(3)
7
(3)
8
.5
66.7
69.9
76.2
79.4
82.6
84.1
85.7
88.9
90.5
92.9
4
101.6
104.8
(5)
133.421A1321D13
(5)
142.9
152.4
165.1
177.821G1221D12
203.221E1221D12
12A10
1G3
1G4
1G1
4G1
4G1
4G3
4G1
1G12
4G1
4G14G
1
4G12
21A5
16G1
16G3
16G1
12D10
1D3
1D4
1D1
4C1
4C1
4D3
4H1
1D12
4D1
4D1
4D1
4D4
4D12
16D1
16C3
16C1
11/32
7/16
1/2
5
11/16
3/4
1-1/8
1-1/2
-
1-5/841.39F89B8
8.7
11.1
12.7
17.5
19
28.6
38.1
5A13
5G5
12G13
8G8
8G10
9G8
9F8
5D13
5B5
12B13
8C8
8B10
9B8
9B8
4-1/8
4-5/8117.513G313B8
5
6-1/8
8-1/8
104.8
(2)
6
152.4
155.6
7
177.8
8203.218G818B8
206.4
127
14G8
13G12
13G3
13G4
13G3
18G8
SIGNAL RANGE
18 to 30 psig (1.2 to 2.0 bar)
2
50.8
2-1/8
(8)
2-1/8
2-5/16
-
2-1/2
2-7/8
3
3-1/8
3-1/4
3-7/16-87.3
-
-
4
6. Use with high pressure bellows and spring retainer spacer 1J2233 46172; for additional
information, see table 7.
7. Use spring retainer spacer 1P3957 X012; for additional information, see table 7.
8. For use with Type 480-12 or 480-15 size 20 actuators.
9. For Type 3570P signal range codes, contact your Fisher sales office or sales
representative.
15G8
545415G1
15F5
58.7
15G1
63.57315F1
14G8
76.2
14G8
79.4
14G8
82.6
14G8
14G8
101.6
14G8
15B8
15B1
15B5
15C1
15A1
14B8
14B8
14B8
14B8
14B8
14A8
3/4
1-1
1-1/2
3-1/8
3-1/4
4
4-1/8
-
-
8-1/8
19
5G10
2
38.1
50.8
76.2
79.4
82.6
8F5
4F8
9G8
9F8
9F8
14E8
16F8
18F1
2
3
(5)
101.6
104.8
(4)
(2)
(4)
206.4
6. For positioners with two relays (Type 3570, 3570C,
3570P, 3570PC, and 3571 positioners), observe the
relay output pressures. If the cylinder gauges are
present as shown in figure 2, read the cylinder top and
cylinder bottom gauges or use clip-on test pressure
gauges. The two relay output pressures should be
approximately equal [within 5 psig (0.3 bar)] and
should be approximately 75 percent of the supply
pressure. For example, if the supply pressure is 100
psig (7 bar), the two relay output pressures should be
13B12
within 5 psig (0.3 bar) of each other, and should be
approximately 75 psig (5.2 bar).
14B8
13B3
13B4
13B3
18B8
5D10
8C5
4D8
9H8
9C8
9C8
14D8
16D8
18D1
4. Set the input signal pressure at the mid-point of its
range [9 psig (0.6 bar) in this example]. Observe the
valve travel indicator scale attached to the yoke. The
indicator disk should be somewhere between the open
and closed positions.
5. Loosen the locknut directly below the bias spring
seat (see figure 3) and adjust the bias spring up or
down until the valve travel indicator disk shows that
the valve plug is somewhere between the open and
closed positions. Upward movement of the bias spring
adjustment causes downward travel of the valve stem.
10
CAUTION
The relays in the Type 3570C and 3570P C
positioners use a locknut (key 29P, figure
11) on the nozzl e (key 29Q). If the nozzl e
is rotated when the locknut is tight, damage to the relay diaphragm might result.
Always use a wrench on the no zzl e to
prevent it from turni n g while loosening or
tightening the locknut.
3570 Series
(1)
(3)
PART NUMBER
()
2K5255-R
A1285-2/IL
Figure 5. Typical Frequency Response for a T
3570C Positioner Mounted on a T
Table 5. Range
Code NumberPart Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
1. The range spring code number is the first number given in each signal range code
listed in table 4. For example, for a signal range of 0 to 15 psig (0 to 1.0 bar), an
actuator travel of 9/16-inch (14.3 mm), and direct action, the signal range code from
table 4 is 6G3. The appropriate range spring is indicated by “6”.
2. Range springs do not have a color code. All range springs are silver.
3. The first six numbers of a range spring part number is also the tag number. For
example, a range spring with part number 1H8914 000A2 has a tag number of
1H8914. Tags are attached to the parts at the time the parts are manufactured.
If the relay output pressures are not at the values
mentioned, adjust the nozzles. Counterclockwise rotation of either nozzle will move the nozzle closer to the
beam and will increase relay output pressure.
For all 3570 Series positioners, examine the end of the
beam near the bias spring (see figure 3). The beam
should be approximately centered between the twoEring travel stops. Observing the caution above for
Type 3570C and 3570PC positioners, rotate the
nozzle(s) to center the beam between the E-rings. For
Table 6. Bias Spring
Code
Letter
A
B
C
D
E
F
G
H
1. The bias spring code letter is the letter given in each signal range code listed in
table 4. For example, for a signal range of 0 to 15 psig (0 to 1.0 bar), an actuator
travel of 9/16-inch (14.3 mm), and direct action, the signal range code from table 3
is 6G3. The appropriate bias spring is indicated by “G”.
2. It is necessary to add the bias spring seat (key 8) to a unit when changing from
an extensin type spring (key 9) to a compression type spring (key 48).
3.Compression type bias spring (key 48).
4. Extension type bias spring (key 9).
CODE
NUMBER
1
2
3
4
5
7
8
10
12
13
1. Code numbers 6, 9, and 11 are not used.
2. Refer to figure 3.
3. The spring retainer code number is the second number given in each signal
range code listed in table 4. For example, for a signal range of 0 to 15 psig (0 to 1.0
bar), an actuator travel of 9/16-inch (14.3 mm), and direct action, the signal range
code from table 4 is 6G3. The appropriate spring retainer is indicated by “3”.
OVERALL
LENGTH
InchesmmInchesmm
1-5/8
2-1/16
2-1/4
3-11/16
3-13/16
1. Refer to figure 3.
2. The spacer number is the first 6 characters of the part number and is stamped on
the part.
positioners with two relays, the relay output pressures
must be approximately equal [within 5 psig (0.3 bar)]
and approximately 75 percent of supply pressure after
the beam is centered.
7. Apply an input signal equal to the low value of the
input signal range [3 psig (0.2 bar) in this example].
Adjust the bias spring (see figure 3) up or down until
the valve travel is at the starting point.
8. Loosen the spring lock (see figure 3) and slowly
increase the input signal toward the high end of the
input signal range [15 psig (1.0 bar) in this example]. If
the valve travel is less than its expected range, increase the travel by adjusting the range spring counterclockwise. If the valve travel reaches the end of its
11
3570 Series
A1088-1/IL
Figure 6. Bellows Mounting for Direct and Reverse Action
valve assembly out of service. To avoid
personal injury or property damage
caused by uncontrolled process pressure, provide a temporary means of control for the process before taking the assembly out of service.
Before removing the input signal and
supply pressure connections from the
positioner, remove the input signal and
supply pressure sources from the
connections. The sudden release of
pressure can cause personal injury or
property damage.
Note
Changing the positioner action might
require changing the bias spring and/or
the spring retainer. Refer to table 4 for
correct signal range codes. Refer to the
Maintenance section for disassembly
and assembly procedures.
expected range with an input signal less than the high
value of the input signal range, decrease the travel by
adjusting the range spring clockwise.
9. Repeat steps 7 and 8 until the valve plug or travel
indicator action corresponds to the input signal requirements of the application [3 to 15 psig (0.2 to 1.0
bar) in this example].
10. Lock the range spring and the bias spring seat in
position. The positioner is then ready for operation.
11. If the positioner is unstable and adjustment does
not correct the problem, it might be due to unwanted
fluctuations in the input signal. A restrictor assembly
(key 47, figure 11) can be installed in the input signal
circuit to dampen these fluctuations. The restrictor
might help to minimize instability. To take the restrictor
out of service, exchange the location of the restrictor
with that of the bellows mounting screw (key 46, figure
11).
12. Replace the cover (key 39) on the positioner.
Changing Positioner Action
The instructions given below are to be used after the
springs have been changed or if no spring change is
required. Numbered parts mentioned in this section
are shown in figure 6 unless otherwise noted.
WARNING
The following procedures require taking
the positioner, actuator, and control
Changing to Reverse Action
1. Bypass the control valve and shut off the input signal line and the supply pressure line to the positioner.
2. Loosen the four thumb screws on the underside of
the positioner base and remove the cover.
3. Two bellows posts are provided. The posts are
screwed into storage holes in the positioner base immediately above the CYLINDER and INSTRUMENT
connections. Unscrew these posts.
Note
An optional restrictor (see the top view
in figure 6) can be found in place of one
of the bellows mounting screws (number 1). If so, note the location of the restrictor and replace it in the same location during reassembly. The restrictor
has a hex head; the mounting screws do
not.
4. Remove the four mounting screws (numbers 1 and
2) and lift out the bellows assembly.
5. Screw the bellows posts (number 3) into the holes
where the screws (number 1) originally were.
6. Invert the bellows and replace the screws (numbers 1 and 2).
7. Refer to the adjustment procedures to check operation of the positioner.
8. Make a notation on the action label (key 43, figure
11) that the action of the positioner has been changed.
9. Replace the cover (key 39) on the positioner.
12
3570 Series
Changing to Direct Action
1. Bypass the control valve and shut off the input signal line and the supply pressure line to the positioner.
2. Remove the positioner cover by loosening the four
thumb screws on the underside of the base.
Note
An optional restrictor (see the top view
in figure 6) can be found in place of one
of the bellows mounting screws (number 1). If so, note the location of the restrictor and replace it in the same location during reassembly. The restrictor
has a hex head; the mounting screws do
not.
3. Remove the four mounting screws (numbers 1 and
2), bellows, and bellows posts (number 3).
4. Invert the bellows and reinstall it in the positioner.
Secure the bellows with the four screws (numbers 1
and 2). Screw the bellows posts into the storage holes
provided in the base immediately above the cylinder
and instrument connections.
5. Refer to the adjustment procedures to check the
operation of the positioner. If the input signal range
has not been changed, adjustment of the range spring
might not be necessary.
6. Make a notation on the positioner action label (key
43, figure 11) that the action of the positioner has
been changed.
7. Replace the cover (key 39) on the positioner.
Split Range Operation
The 3570 Series valve positioners are suitable for split
range operation. In split range operation, two or more
control valves are operated by one output signal from
a single control device. When two control valves are
split ranged, one valve strokes fully with one half the
input signal range and the second valve strokes fully
with the other half of the input signal range.
Valve positioners shipped from the factory for split
range operation are constructed and adjusted accordingly. If it is necessary to convert an existing positioner
to one suitable for split range operation, refer to table
4. If the application requires a selection not listed in
table 4, consult your Fisher sales office or sales representative to determine the new parts required. For
most changes, a new range spring and possibly a new
bias spring will be required. A new range spring retainer might also be required for Type 3570, 3570C, 3572,
and 3573 positioners.
When corresponding with your Fisher sales office or
sales representative, supply all information possible
about the desired operating conditions and the serial
numbers of the control valve assembly. This information will facilitate the proper selection of the required
parts.
To change an existing valve positioner to one suitable
for split range operation, refer to the range and bias
spring removal and replacement procedures in the
Maintenance section. Be certain the required new
parts are on hand before beginning any maintenance
operation.
Initial Range Spring Extension
Procedures for Type 3570P And 3570PC
Positioners
This procedure must be performed whenever the
range spring has been changed or the positioner has
been removed. Key numbers used in this procedure
are shown in figure 13 except where indicated.
1. With the cap screw (key 87) removed, hook the
small ball of the positioner cable (key 91) into the slot
of the smaller portion of the cable spool (key 96). Wind
the cable on the spool until the coils of the range
spring (key 18, figure 11) are slightly separated. Be
certain the cable is wound so that it comes off the side
of the spool opposite the access opening and that the
cable cannot cross itself on the spool.
2. Install the ball end of the actuator cable (key 92)
into the slot of the large portion of the spool that is
closer to the access opening. Wrap the cable on the
spool as many times as possible, then bring the cable
out through the bottom of the positioner extension. Be
certain the cable is wound so that it comes off the side
of the spool opposite the access opening and that the
cable cannot cross itself on the spool. Attach the cable
to the cable strap (key 93), leaving approximately a
1/32-inch (0.8 mm) gap between the cable eye and
cap screw head (key 94).
3. With the actuator piston rod completely retracted
and the range spring coils slightly separated, attach
the cable strap to the actuator feedback arm. Use the
set of cable-strap holes closest to the range spring.
Turn the spring cap (key 86) one turn counterclockwise and install one cap screw (key 87).
4. Adjust the range spring (key 18, figure 11) to obtain
full travel for the input signal range (span adjustment).
Refer to step 7 of the adjustment procedures. Adjustment of the bias spring (zero adjustment) does not
need to be done at this time.
5. Remove the screw from the spring cap and slowly
release the torsion spring force by turning the spring
cap clockwise. Disconnect the cable strap from the
actuator and remove all range spring extension by rotating the cable spool.
13
3570 Series
6. Rotate the cable spool to obtain the correct initial
range spring extension. Each full revolution of the
spool extends the range spring 2 inches (50.8 mm)
[1/4-inch (6.4 mm) for 1/8 revolution]. If the initial
range spring extension is not specified, calculate it
using one of the equations given below. Round off the
amount of extension (e) obtained from the equation to
the next higher 1/4 inch (6.4 mm).
T
e=
(standard bellows)
1.87 (Pn)
T
e=
(optional high pressure bellows)
1.25 (Pn)
where:
e = initial range spring extension required in inches
T = actuator travel in inches
Pn = input signal span in psi (for example, 12 psi for
a 3 to 15 psig input signal range)
or
where:
e = initial range spring extension required in mm
T = actuator travel in mm
Pn = input signal span in bar (for example, 0.8 bar for
a 0.2 to 1 bar input signal range)
7. If necessary, move the actuator cable ball to the
spool slot nearer the access opening. With the actuator piston rod fully retracted and the range spring at
the correct initial extension, attach the cable strap to
the actuator feedback arm. Use the set of cable strap
holes that is closest to the tapped holes in the feedback arm.
8. Refer to the positioner adjustment procedures.
Principle of Operation
Type 3570, 3570C, 3570P, 3570PC, and
3571 Valve Positioners
Refer to the schematic diagram in figure 7. The pneumatic output signal from a control device is piped to
the positioner bellows. For explanation purposes, assume this signal has increased. The bellows expands
and moves the beam, which pivots around a fixed
point and simultaneously uncovers the nozzle of relay
B and covers the nozzle of relay A. The nozzle pres-
BELLOWS
REVERSED
RANGE SPRING
BIAS
SPRING
CYLINDER
A1067-1 / IL
Figure 7. Schematic Diagram of T
RELAY “B’’
R
SUPPLY
470 Series Pneumatic Piston Actuator
INPUT
SIGNAL
R
SUPPLY
YOKE
INPUT SIGNAL PRESSURE
SUPPLY PRESSURE
TOP CYLINDER PRESSURE
BOTTOM CYLINDER PRESSURE
NOZZLE PRESSURE
ype 3570 Positioner with a
POSITION
RELAY “A’’
R = RESTRICTION
sure in relay A increases due to the restriction created
by the beam covering the nozzle. Through relay action, the pressure to the top of the piston increases. At
the same time, relay B reacts to the change in beam
position to decrease the pressure to the underside of
the piston. These unbalanced pressures move the actuator piston down.
In the Type 3570 and 3570C positioners, the piston
movement is fed back to the beam by means of a
range spring, which is connected to the beam and to
the piston rod extension. In the Type 3570P, 3570PC,
and 3571 positioners, the feedback is provided to the
range spring by a cable or wire that is connected to
the actuator-valve stem connector. The downward
movement of the piston rod extension extends the
range spring until the torque on the beam balances the
torque exerted by the instrument bellows.
As the input signal decreases, the reverse action
takes place. The bellows contracts, and as the beam
pivots, it covers the nozzle of relay B and uncovers the
nozzle of relay A. Through relay action, the pressure
below the piston increases and the pressure above the
piston decreases to move the piston upward.
Type 3572 and 3576 Valve Positioners
Refer to the schematic diagram in figure 8, which
shows the Type 3572 positioner mounted on a Fisher
14
3570 Series
In the Type 3572 positioner, piston movement is fed
back to the beam by means of a range spring, which is
connected to the beam and the piston rod extension.
As the piston rod extension moves downward, the
range spring is extended until the torque of the beam
balances the torque exerted by the instrument bellows.
In the Type 3576 positioner, the feedback is provided
to the range spring by a wire that is connected to the
actuator-valve stem connector.
As the input signal decreases, the reverse action
takes place. The bellows contracts, and as the beam
pivots, it uncovers the relay nozzle. Through relay action, the pressure on top of the piston decreases, and
the force of the actuator spring moves the piston upward.
Type 3573 and 3577 Valve Positioners
Refer to the schematic diagram in figure 9, which
shows the Type 3573 positioner mounted on a Fisher
Type 473 pneumatic piston actuator. For the Type
3577 positioner, the principle of operation is identical
to the Type 3573 positioner, but the actuator can be
direct or reverse acting.
CR4006-A
A1084-1/IL
Figure 8. Schematic Diagram of T
T
ype 472 Pneumatic Piston Actuator
ype 3572 Positioner with a
Type 472 pneumatic piston actuator. For the Type
3576 positioner, the principle of operation is identical
to the Type 3572 positioner but the actuator can be a
direct or reverse acting pneumatic diaphragm actuator.
The pneumatic output signal from a control device is
piped to the positioner bellows. For explanation purposes, assume this signal has increased. The bellows
expands and moves the beam, which pivots around a
fixed point and covers the relay nozzle. The nozzle
pressure in the relay increases due to the restriction
created by the beam covering the nozzle. Through
relay action, the pressure above the piston overcomes
the force exerted by the actuator spring, and the piston moves downward. This changes the valve plug
position.
The pneumatic output signal from a control device is
piped to the positioner bellows. For explanation purposes, assume this signal has increased. The bellows
expands and moves the beam, which pivots around a
fixed point and uncovers the relay nozzle. The nozzle
pressure decreases due to the uncovering of the
nozzle by the beam. Through relay action, the pressure to the underside of the piston decreases. The
force exerted by the actuator spring overcomes the
force of the pressure below the piston, and the piston
moves downward. This changes the valve plug position.
In the Type 3573 positioner, piston movement is fed
back to the beam by means of a range spring, which is
connected to the piston rod extension. The downward
movement of the piston rod extension extends the
range spring until the torque of the beam balances the
torque exerted by the instrument bellows.
In the Type 3577 positioner, feedback is provided to
the range spring by a wire that is connected to the actuator-valve stem connector.
As the input signal decreases, the reverse action
takes place. The bellows contracts, and as the beam
pivots, it covers the relay nozzle. Through relay action,
the pressure on the underside of the piston increases
to overcome the force exerted by the actuator spring,
and the piston moves upward.
15
3570 Series
CR4007-A
A1082-1/IL
Figure 9. Schematic Diagram of T
T
ype 473 Pneumatic Piston Actuator
ype 3573 Positioner with
chamber between the two relay diaphragms. Due to
the restricting effect of the flapper over the nozzle,
pressure builds up in the chamber between the diaphragms, forcing the diaphragm head assembly E
downward to open supply valve B, allowing output
pressure to increase.
The supply pressure flows past supply valve B to increase the output pressure to the actuator cylinder.
The cylinder pressure (relay output pressure) also acts
on the area D. This provides an air feedback that returns the diaphragm head assembly E and the movable nozzle F to their original positions, thus preventing any further increase in output pressure. The
feedback arrangement and the movable nozzle ensure
accurate and stable positioning of the actuator piston
without introducing cycling or over-correction. After
any change in the output pressure, supply valve B and
exhaust valve C always return to the closed position to
put the nozzle back in its original, or equilibrium, position. The spring behind supply valve B aids in closing
the valve as the diaphragm head assembly is forced
upward.
When the beam flapper moves away from the nozzle
F, the supply pressure bleeds out at a greater rate
than it enters through the fixed restriction R. The pressure then decreases in the chamber between diaphragms. The force of the cylinder pressure acting on
area D pushes diaphragm head assembly E upward,
opening exhaust valve C. Cylinder pressure bleeds
through the exhaust port to atmosphere. As the cylinder pressure decreases and the force on area D decreases, the force of the nozzle pressure in the chamber between the diaphragms returns the assembly to
its original position. The unit is again in equilibrium, but
at a lower nozzle pressure and a lower output pressure.
Relay Operation
Refer to figure 10, which shows a sectional view of a
typical relay.
Supply pressure reaches the relay(s) through passages in the positioner base and is channeled to fixed
restriction R and to point A between the supply valve
B and the balancing O-ring of the relay valve. The
fixed restriction is an integral part of the relay restriction plug and wire assembly G. The orifice in nozzle F
is larger than the fixed restriction. This allows the supply pressure to bleed to atmosphere faster than it enters the unit through the fixed restriction when the
beam flapper is away from the nozzle.
Assume that a change in the input signal causes the
beam flapper to cover the nozzle of a relay. The supply pressure flows through fixed restriction R into the
16
Each relay has a 4:1 ratio between the nozzle pressure and the output pressure. For example, a 10 psig
(0.7 bar) nozzle pressure change, produces a 40 psig
(2.7 bar) output pressure change; a 20 psig (1.4 bar)
nozzle pressure change produces an 80 psig (5.5 bar)
output pressure change. With a constant input signal
pressure, the internal parts of the relay are at equilibrium with the supply and exhaust valves closed.
Maintenance
WARNING
Avoid personal injury from sudden release of process pressure. Before performing any maintenance operations:
F
40A8972-B/DOC
E
R
D
G
CLEAN-OUT
PLUNGER
SUPPLY
NOTES:
1
OUTPUT PORT IS SHOWN
90 DEGREES TO THE FRONT OF
ACTUAL LOCATION
W0700-1/IL
Figure
10. Sectional V
A
B
A–SUPPLY PRESSURE AREA
B–RELAY OUTPUT PRESSURE VALVE
C–EXHAUST VALVE
D–RELAY OUTPUT PRESSURE AREA
E–DIAPHRAGM HEAD ASSEMBLY
F–NOZZLE
G–RELAY RESTRICTION PLUG ASSEMBLY
R–FIXED RESTRICTION
iew of a T
ypical Relay
EXHAUST
C
1
OUTPUT
D 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.
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 Use lock-out procedures to be sure
that the above measures stay in effect
while you work on the equipment.
Troubleshooting
If the positioner causes sluggish or erratic operation or
the malfunctioning of the actuator, first, be certain that
3570 Series
the range springs, bias springs, and spring retainer are
correct for the application. Refer to table 4 or consult
your Fisher sales office or sales representative.
If the springs and spring retainer are correct, and careful adjustment of the unit does not produce smooth
and satisfactory operation, check the following points.
Key numbers used in this procedure are shown in figure 11 except where indicated. Figure 2 shows part
locations.
1. Clean out the primary orifice on each relay by depressing the clean-out plunger. The plunger is located
in the orifice assembly (key 29S). This operation runs
a fine wire through the orifice to clear the hole.
2. Check the nozzle (key 29Q) of each relay for plugging. To clean, swing the flapper (key 12) away from
the nozzle by loosening the screw that holds the flapper in place.
CAUTION
The relays used in Type 3570C and
3570PC positioners use a locknut (key
29P, figure 12) on the nozzle (key 29Q,
figure 12). If the nozzle is rotated when
the locknut is tight, damage to the relay
diaphragm will result. Always use a
wrench on the nozzle to prevent it from
turning while loosening or tightening
the locknut.
Unscrew the nozzle and run a fine wire through it. Do
not enlarge the hole. Also check the surface of the
flapper for any accumulation of dirt or foreign materials.
3. Check the bellows assembly for damage, misalignment, or leakage. Also check all gasketed joints for
leakage. Use soap solution for leak detection.
4. Check the beam for damage, binding or rubbing
against stationary parts. Check the flexure strip
screws (key 17) for tightness.
5. If the positioner operation has improved, refer to
the adjustment procedures.
6. If the positioner operation does not improve, go to
step 7.
7. Unscrew the three machine screws (key 31) from
each relay and remove the relays.
8. Check the two relay diaphragms (keys 29F and
29K) for holes or cuts. Note that the larger of the two
diaphragms has five holes in it: four holes are for the
flange screws and one permits the flow of air from the
primary orifice to the chamber between diaphragms.
9. Check the relay valve plug (key 29B) for nicks,
cuts, or dirt. Also check both inlet and exhaust ports.
17
3570 Series
10. Check all O-rings for wear or damage.
11. Check all metal parts for damage. Do not attempt
to remove the stainless steel bushing in the relay
body. If this part is damaged, install a new relay body
(key 29A).
12. Check the clean-out wire assembly in the core
and orifice assembly (key 29S).
13. When reassembling, clean all parts and coat all
O-rings with a good quality grease that is compatible
with the elastomer O-rings. The grease should be of
the type that does not readily oxidize to form a hard
deposit. It should also resist being carried away from
the lubricated surfaces by the supply pressure.
14. When replacing the relay flange (key 29N), depress the nozzle and hold it down until the four flange
screws (key 29R) have been tightened. This ensures
the proper amount of slack in the two diaphragms.
15. Mount the relays in their respective positions on
the positioner pedestal, making certain that the relay
gasket (key 30) is in good condition and is in place.
16. If the positioner operation is still sluggish, a slight
adjustment of the bias spring post (see figure 3) might
be necessary. Loosen the locknut and rotate the post
in half-turn increments, checking after each half turn
for proper operation. Rotate the post no more than two
turns from the position shown in figure 3. Refer to the
adjustment procedures after rotating the post to check
the position of the post and beam assemblies.
Converting a Type 3570 Valve Positioner
to a Type 3570C Valve Positioner
If desired, tire valves can be substituted for pressure
gauges. Also, locking relay nozzles can be added on
any 3570 Series positioner. This provides the
construction that is standard with the Type 3570C and
3570PC positioners.
Key numbers used in this procedure are shown in figure 11 except where indicated. When reassembling,
coat all pipe threads with a good quality pipe thread
compound.
3. Disconnect the tubing assemblies (keys 28 and 45)
from the base and from the gauges (keys 24 and 25).
Unscrew the hex nuts (key 27) from the back of the
gauges and remove the gauges (keys 24 and 25).
4. Unscrew the pressure gauge (key 54) from the
gauge adaptor (key 29U).
5. Unscrew and remove the nozzle and spring (keys
29Q and 29P) from each relay.
6. The gauge bracket (key 5) can be removed if desired. To remove it, loosen the locknut (key 7) and remove the bias spring post and cap screw (keys 6 and
32). When replacing the bias spring post, be sure that
the bottom of the post thread is positioned as shown in
figure 3 for proper positioning of the E-ring travel
stops. This alignment can be verified visually through
the vent port.
7. Use compression plugs (key 52) to plug the holes
opened in the base when the tubing is removed.
CAUTION
Never rotate the nozzle (key 29Q) when
the locknut (key 29P) is tight, or damage
to the relay diaphragm will result. Always use a wrench on the nozzle to prevent it from turning while loosening or
tightening the locknut.
8. Install the locknut and nozzle (keys 29P and 29Q)
on each relay.
9. Install the tire valve (key 26, figure 12) into the
gauge adaptor (key 29U).
10. Install the service tee and tire valve adaptor (keys
49 and 53, figure 12) into the CYLINDER connection.
Connect the pressure line that runs to the lower part of
the cylinder to the service tee.
11. Install the pipe nipple, pipe tee, and tire valve
adaptor (keys 50, 51, and 53, figure 12) into the
INSTRUMENT connection. Connect the input signal
line to the pipe tee.
12. Refer to the adjustment procedures.
Range Spring
1. Isolate the control valve from the line pressure, release pressure from both sides of the valve body, and
drain the process media from both sides of the valve.
If using a power actuator, also shut-off all pressure
lines to the power actuator, release all pressure from
the actuator. Use lock-out procedures to be sure that
the above measures stay in effect while you work on
the equipment.
2. Loosen the knurled screws (key 38) and remove
the cover (key 39).
18
Disassembly
Unless otherwise directed, key numbers refer to figures 11 and 12.
WARNING
The following procedure requires taking
the positioner, actuator, and control
3570 Series
valve assembly out of service. To avoid
personal injury or property damage
caused by uncontrolled process pressure, provide a temporary means of control for the process before taking the assembly out of service.
Before removing the input signal and
supply pressure connections from the
positioner, remove the input signal and
supply pressure sources from the connections. The sudden release of pressure can cause personal injury or property damage.
1. Bypass the control valve and shut off the input signal and the supply pressure lines to the positioner.
2. Remove the positioner cover (key 39).
3. Loosen the spring lock (see figure 3) that holds the
range spring (key 18) to the beam.
4. Disconnect the other end of the range spring by
performing one of the following steps:
D For Type 3570, 3570C, 3572, and 3573 posi-
tioners, use a screwdriver to remove the spring re-
tainer (key 19, figure 3) from the piston rod extension.
The action of the positioner can be reversed in the
same manner as described in the changing positioner
action procedures. However, before attempting to reverse the action, see table 4 or consult your Fisher
sales office or sales representative to determine if any
different parts are required.
Bias Spring
Disassembly
1. Refer to figure 3. Remove the top E-ring travel
stop.
2. Loosen the locknut securing the bias spring seat in
place. Then rotate the adjusting screw until the spring
force is at a minimum.
3. Loosen the locknut that secures the bias spring
post to the positioner base. Using a screwdriver in the
slot in the top of the post, unscrew the post from the
base.
4. Tilt the bottom of the post out and remove the post
from the beam.
5. Remove the locking nuts and the spring seat from
the bias spring post.
D For Type 3570P and 3570PC positioners (see
figure 12), remove the screws (key 87), from the cap
(key 86) and rotate the cap clockwise to remove all
torsion spring force. Disconnect the actuator cable
(key 92) from the cable strap (key 93). Unhook the
positioner cable (key 91) from the cable spool (key
96).
D For Type 3571, 3576, and 3577 positioners,
loosen the set screw found in the spring retainer (key
56A, figure 14) and remove the spring wire (key 56D)
from the retainer.
5. Remove the range spring from the beam by
rotating the range spring counter clockwise.
Assembly
1. Install the new range spring. For Type 3570,
3570C, 3572, and 3573 positioners, also install the
spring retainer. See figures 3 or 11.
2. Reconnect the range spring to the piston rod extension (Type 3570, 3570C, 3572, and 3573 positioners)
or the feedback wire (Type 3571, 3576, and 3577 positioners, figure 14). For Type 3570P and 3570PC positioners, install the positioner cable (key 91, figure 13)
in the range spring so that the large ball on the cable
seats in the conical portion of the spring.
3. Install the spring lock (key 20, figure 11). Adjust the
positioner per instructions in the adjustments procedures.
Assembly
1. Install the new bias spring, spring seat, and locking
nuts on the bias spring post.
2. Replace the bias spring post into the beam and
install the top E-ring travel stop.
3. Install the bias spring post into the base. Be certain
that the bottom of the post thread is positioned as
shown in figure 3. Ensure that the beam does not rub
on the post.
4. For Type 3570P and 3570PC positioners, go to the
initial range spring extension procedures for Type
3570P and 3570PC positioners.
5. Adjust the positioner as described in the adjustments procedures.
The action of the positioner can be reversed in the
same manner as described in the changing positioner
action procedures. However, before attempting to reverse the action, see table 4 or consult your Fisher
sales office or sales representative to determine if a
different retainer, different range springs or different
bias springs are required.
Parts Ordering
A serial number is assigned to each positioner. The
serial number is stamped on the nameplate. Always
refer to the serial number when corresponding with
your Fisher sales office or sales representative regard-
19
3570 Series
ing spare parts or technical information. When ordering replacement parts, also specify the complete
11-character part number from the parts kits or parts
list information.
Parts Kits
Note
Parts kits for the 3570 Series positioners contain the
gaskets, diaphragms, and O-ring seals as specified by
the type and temperature limitations. Parts are for
Type 3570, 3570C, 3570P, and 3570PC positioners.
For the Type 3570
For the Type 3570 (hi-temp. const.)
For the Type 3570C
For the Type 3570C (hi-temp. const.)
Diagnostic Test Connection Kits
Kit includes pipe tee, pipe nipple, pipe
bushings, connector body, and body
protector used with the FlowScanner
Also, part number provides correct
quantities of each item.
For Diaphragm Actuators
Stainless steel12B8042X012
Steel12B8042X022
For Piston Actuators
Stainless steel12B8043X012
Steel12B8043X022
Pipe Thread Sealant (not furnished with
hardware or connectors)
(1)
.
R3570 X00012
R3570 X00H12
R3570 CX0012
R3570 CX0H12
KeyDescriptionPart Number
9Bias Spring, extension type
Color Code:
Black
Pink1J2933 000A2
Dark green
10Retaining ring, pl steel (2 req’d)
11Beam, aluminum
12Flapper, SST (2 req’d)
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. 1974, 1992; All Rights Reserved