Dwyer 275 User Manual

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Bulletin F-98

Series 275 PRECISOR®III Electro-Pneumatic Positioner

Specifications - Installation and Operating Instructions

Series 275 PRECISOR

®

III Electro-Pneumatic Positioner controls

valve stroke accurately using an input signal of 4 to 20 mA from the
controller. In addition, a highly efficient microprocessing operator built
into the product. Performs various powerful functions such as Auto
calibration, PID control, Alarm and Hart®protocol.

FEATURES

• LCD allows user to directly check the positioner condition in the field.

• Endures severe vibration.

• Operates normally regardless of changes in supply pressure during
operation.

• Simple to use auto calibration.

• Easily equipped on small actuators because of its small size.

• Low air consumption reduces operating cost.

• Can be used in low voltage (8.5V), leaving no limitation in controller.

• Variable orifice is applied in case of a small actuator, the hunting is
controlled to the optimum condition during operation.

• HART®communication available for configurating parameters or

monitoring the valve position.

• Analog feedback signal (4 to 20 mA).

• The adjustment of valve characteristics available.

• Specific flow control is available with setting 16 points at users’
command.

• Tight Shut-Close and Shut-Open can be set in the programming

menu.

• PID parameters can easily be adjusted in the field without additional
communicator.

• Split ranges such as 4-12 mA, 12-20 mA are available.

• The positioner can manually actuate the valve or damper.

SPECIFICATIONS
Input Signal: 4-20 mA DC.
Input Impedance: 460 Ohm max @ 20 mA DC.
Material: Aluminum diecasting.
Air Supply: 20 to 100 psi (1.4 to 6.9 bar).
Air Connection: 1/4˝ NPT.
Gage Connection: 1/8˝ NPT.
Conduit Connection: 1/2˝ NPT.
Linearity: ±0.5% of full scale.
Hysteresis: ±0.5% of full scale.
Sensitivity: ±0.2% of full scale.
Repeatability: ±0.3% of full scale.
Air Consumption: below 0.07 scfm (2 LPM) at 20 psig (1.4 bar)

supply.

Flow Capacity: 2.5 scfm (70 LPM) at 20 psig (1.4 bar) supply.
Stroke: 0 to 90°.
Enclosure Rating: NEMA 4X (IP66).
Ambient Temperature: Operating: -40 to 185°F (-40 to 85°C).
Weight: 3.3 lb (1.5 kg).
Lever: 175: 0.39 to 1.57˝ (10 to 40 mm); 275: NAMUR.

DWYER INSTRUMENTS, INC.

P.O. BOX 373 • MICHIGAN CITY, INDIANA 46360, U.S.A. Fax: [phone] e-mail: [e-mail]

Phone: [phone] www.dwyer-inst.com

HART® is a registered trademark of Hart Communication Foundation

page 2

20

450

450

Series 275 Installation

Series 275 is designed for rotary motion valves such as Dwyer
Instruments ball and butterfly valves using rack and pinion, scotch yoke
or complex type actuators whose stem is rotated 90°. Series 275 p ­ositioners consist of the following components:

1. Series 275 main body

2. Fork lever and lever spring to attach on actuator

3. 1 bracket

4. Four hex bolts M8x1.25P

5. Four M8 plate washers

eries 275 installation example

S

eries 275 installation example of fork lever

S

1. Typical actuator stem heights (H) are 0.79, 1.18 and 1.97 inches (20,
30, and 50 mm). After checking H, assemble brackets following
previous guidelines. The bracket is set at 0.79˝ (20 mm) in the
factory.

ctuator Stem (H)

A

Actuator

2. Attach bracket to the actuator using hex bolts. The diameter of the
bracket bolt holes are 0.24˝ (6 mm). Use spring washers or thread
lock compound so the bolts will not be loosened by vibration or
impact. The direction of the bracket varies by operating conditions,
but the normal direction is depicted in the following picture. That is,
when the piping of actuator and Series 275 is as shown in direction
A, the bracket hole and indicator attached on the bottom of the Series
275 main shaft should be mounted in the same direction.

Direction A

Series 275 installation example of Namur shaft

Installing Series 275 with bracket

Series 275 is supplied with a standard bracket. The bracket consists of
two parts and is used with a NAMUR shaft. The bracket is assembled in
the factory based on 0.79˝ (20 mm) of actuator stem height. If the
actuator stem height is higher, such as 1.18˝ (30 mm), or 1.97˝ (50 mm),
reassemble the bracket adjusting to the actuator stem height. Refer to
the table below to check hole positions.

Bracket assembly method by actuator stem height H

Actuator stem

height (H)

20 mm
30 mm
50 mm

A-L

H: 20
H: 30
H: 50

Markings of bolt holes

B-L

H: 20, 30
H: 20, 30

H: 50

A-R

H: 20
H: 30
H: 50

B-R

H: 20, 30
H: 20, 30

H: 50

Attachment direction of bracket and actuator

3. Set the rotation position of actuator stem as the initial zero point,
which is 0% stroke. For a spring return type actuator, the actuator
stem is always rotated to the zero point without supply pressure,
making it easy to check the zero point. If the actuator is double­acting, check whether the rotation direction of the actuator is
clockwise or counter-clockwise or check the rotation direction of the
actuator using supply pressure.

4. Set the actuator stem as the initial zero point and install a fork lever
as shown in the following picture. Confirm the position of initial zero
point when actuator stem is turned clockwise and counter-clockwise.
Installation angle of fork lever should be about 45 degrees based on
the linear shaft. But the angle is not related to NAMUR shaft.

Counter-Clockwise

Clockwise

Ex) If H is 30 mm, A-L should be locked in H:30 hole, B-L in H:20,30, A-

R in H:30, and B-R in H:20,30 with bolts.

page 3

6~11mm

LCD SCREEN

SMART POSITIONER

5. Once the fork lever position is set, lock the check nuts on the bottom
of the fork lever by turning clockwise. Set the upper height of the fork
lever to 0.24 to 0.43”(6 to 11 mm) lower than the upper height of the
bracket.

Bracket

ork Lever

F

ctuator

A

Installation position of fork lever

6. Attach Series 275 unit to the bracket. Fix the clamping pin on the
main shaft center of the Series 275 into the hole of the fork lever.
Insert the connection bar attached on the main shaft lever into the
fork lever slot to be locked by the fork lever spring. This is to fit the
main shaft of the Series 275 to the center of the actuator stem. If they
are not fitted correctly, too much force on the main shaft will greatly
reduce product durability.

7. Attach Series 275 base and the bracket with hex bolts and plate
washers. It is best to lock the bracket and Series 275 together by
inserting four bolts after checking the position.

Single Acting Actuator

To operate a single acting actuator, connect OUT1 port to actuator
supply pressure port. Close off the OUT2 port with the supplied 1/4˝
NPT plug.

Piping connection example of Series 275 with single acting actuator

Double Acting Actuator

For the Series 275 double acting type, OUT1 and OUT2 ports are used.

Fitting the pin on the Series 275 main shaft into fork lever hole

PIPING CONNECTION
Note:

1. To prevent ingress of moisture, oil and dust, give careful
consideration to the choice of supply pressure compressor and
piping.

2. It is recommended to attach filter or air filter regulator in front of the
supply port of the Series 275 unit.

Conditions of Supply Pressure

1. Dry air with a dew point that is at least 50°F (10°C) lower than that of
the ambient temperature.

2. Free from solid particles. Result of being passed through 5 micron or
finer filter.

3. Does not contain oil or lubricating oil.

4. Comply with ANSI/ISA-57.3 1975(R1981) or ISA S7.3-1975(R1981).

5. Not used beyond the range of 20 to 100 psi (140 to 689 kPa).

6. Set supply pressure of air filter regulator to 10% higher than
operating pressure of actuator.

Conditions of Pipe

1. Remove foreign objects from inside of pipe.

2. Do not use squeezed or broken pipe.

3. To maintain flow rate of Series 275, use a pipe with inner diameter
greater than 0.24˝ (6 mm) (outer diameter 0.39˝ (10 mm)).

iping connection example of Series 275 with double acting actuator

P

Power Connection
Note:

1. Before connecting terminal, power must be shut off.

2. Use ring type terminal against oscillation, impact, etc.

3. Series 275 positioners use 4 to 20 mA DC for power. Minimum
supply current is 3.2 mA (standard type) and 3.8 mA (HART®type).
Maximum supply current must not exceed 24 mA.

4. In order to protect the Smart Positioner, the ground terminals should
be grounded.

5. Use twisted cable with conductor sectional area at least 0.0019 in
(1.25 mm2), and suitable for 600V as on conductor table of NEC
Article 310. Outer diameter of cable should be 0.25 to 0.39˝ (6.35 to
10 mm). Use shielded wire against electromagnetic waves and
noise.

6. Do not install the cable near equipment such as a high-capacity
transformer or motor.

Terminal plate

2

Piping Connection With Actuator

Series 275 can operate as either single or double acting actuators.