Omega Products PX274 Installation Manual

Low Pressure Transducer

PX274, PX275, PX277, and PX278

M2759-0305

SPECIFICATIONS

Accur acy*:± 1%

FS

Overpressure: 10

PSID

Supply Voltage: 12 - 40

VDC

; 12 - 35

VAC (VDC

output

transducers only)

Supply Current:10

M

A

maximum for VDC outp ut

transducers; 20

M

A

maximum for

M

A

output transducers

Enclosure: 18 Ga. C.R. steel NEMA-4 (IP-65) or panel mount
cha ssis

Finish: Baked on enamel PMS2GR88B

Compensated Temperature Range: 25°

F

to 150°F (-4°C to

65°

C

)

T. C . E rr o r:

±

0.0125%/°F (.02%/°C)

Operating Temperature Range: 0°

F

to 175°F (-18°C to 80°C)

Media Compatibility: Clean dry air or any inert gas

Environmental: 10 to 90%

RH

non-condens ing

Te rm in a ti o n: Unpluggable screw terminal block

Wire Size: 12 Ga. maximum

Load Impedance: 1.6K ohms max. at 40

VDC

(

M

A

output

transducers); 1K ohms min. (

VDC

output tr ansducers)

Weight: Enclosure moun t: 1.0 lb. (.45 kg); Panel mo unt: 0.5
lbs. (.25 kg)

*

Includes nonlinearity, hysteresis, and non-repeatability.

INSTALLATION PRECAUTIONS

Do not use on oxygen service, in an explosive or hazardous
environment, or with flammable or combustible material.

Disconnect the power supply before installing the transducer.
Failure to do so can result in electrical shock and equipment
damage.

Make all connections in accordance with the job wiring
diagram and national and local electrical codes.

Use electrostatic discharge precautions such as wrist straps
when installing and wiring the transducer.

Do not exceed ratings for the transducer.

If using grounded AC, ensure that the hot wire is on the [+]
terminal. Also, if using a controller without built-in isolation,
use an isolation transformer to supply the transducer.

This transducer contains a half-wave rectifier power supply
and must not be powered from tr ansformers p owering other
devices with non-isolated full-wave rectifier power supplies.

When multiple transducers are powered from the same
transformer, damage will result unless all 24-gage power
leads are connected to the same power lead on all
transducers. Maintain the correct phasing when powering
more than one transducer from a single transformer.

WIRING

Use 12

AWG

wire maximum for wiring terminals. Use flexible
¼-inch O.D. (5/32-inch I.D.) tubing for high and low pressure
connections.

The

M

A

output transducer must be powered with a 12 - 40

VDC

power supply. The

VDC

output transducer is field selectable

for 0 - 5

VDC

or 0 - 10

VDC

output and can be powered with

either 12 - 40

VDC

or 12 - 35

VAC

.

Wiring the PX-274 and PX-275:

1. Remove the blue terminal block by carefully pulling it

off the circuit b oard.

2. Note the block’s terminal markings on the circuit board.

3. If using an external power supply, connect the supply

voltage wire to the [+] terminal. Connect the power
supply common to the common bus of the controller/
meter. Connect th e input sign al of the cont roller/meter
to the [-] term inal.

4. If using a controller/meter with an internal

power supply, connect the controller/
meter input signal to the [+] terminal.
Connect the cont roller/meter common to the [-]
terminal.

5. Reinsert the terminal block onto the circuit board and

apply power to the transducer.

6. Check for the appropriate output signal using a digital

voltmeter set to DC milliamps connected in series to
the [-] term inal.

Wiring the PX-277 and PX-278:

1. Remove the blue terminal block by carefully pulling it

off the circuit board.

2. Note the block’s terminal markings on the circuit board.

3. Connect the power supply voltage wire to the [+]

terminal and the power supply common to the [-]
terminal.

4. Connect the controller/meter input wire to the [0]

terminal and the controller/meter common wire to the
[-] terminal.

5. Reinsert the terminal block onto the circuit board and

apply power to the transducer.

6. Check the appropriate VDC outpu t using a digital

voltmeter set to DC volts connected to the [0] and [-]
terminals.

PRESSURE RANGES AND JUMPER
CONFIGURATIONS

Jumper Configurations

Jumper Configurations for mA Output Transducers

Jumper Configurations for VDC Output Transducers

CALIBRATION

All transducers are factory calibrated to meet or exceed
published specifications. If field adjustment is necessary,
follow these instructions:

1. Connect a 12 - 40

VDC

or 12 - 35

VAC

power source to the

[+] and [-] terminals.

2. If calibrating an

M

A

output transducer, connect a digital

voltmeter in series to the [-] terminal.

3. If calibrating a VDC output transducer, connect a digital

voltmeter on DC volts across the [0] and [-] terminals.

4. Apply low pressure to the transducer and carefully

adjust the zero tr immer [Z] to obtai n the desired low
output pressure.

5. Apply high pressure to the transducer and adjust the

span trimmer [S] to obtain the desired high output
pressure.

6. Repeat steps 4 and 5 until the transducer is fully

calibrated.

DIMENSIONS

Range A B C D E F G H

0.1 D

(“w.c.)

0 to

.10

-.05 to
.05

——— — — —

01 D

(“w.c.)

— — 0 to 1.0 0 to .5 0 to .25 -.5 to .5

-.25 to
.25

-.125 to
.125

05 D

(“w.c.)

——

0 to

5.0

0 to

2.5

0 to

1.2 5

-2.5 to

2.5

-1.25 to

1.2 5

-.625 to
.625

30 D

(“w.c.)

— — 0 to 30 0 to 15 0 to 7.5

-15.0 to

15.0

-7.5 to

7. 5

-3.75 to

3.75

1250 D

(pa)

——0 to

1250

0 to
625

0 to

312.5

-625 to
625

-312.5
to

312.5

-156.25
to

156.25

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It is the policy of OMEGA Engineering, Inc. to comply with all worldwide safety and EMC/EMI regulations that apply. OMEGA is constantly pursuing
certification of its products to the European New Approach Directives. OMEGA will add the CE mark to every appropriate device upon certification.

The information contained in this document is believed to be correct, but OMEGA accepts no liability for any errors it contains, and reserves the
right to alter specifications without notice.
WARNING: These products are not designed for use in, and should not be used for, human applications.

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Tel: [phone] FAX: [phone]
e-mail: [e-mail]

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®

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®

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®

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Tel: [phone] FAX: [phone]
Toll Free in United Kingdom: 0800-488-488
e-mail: [e-mail]

WARRANTY/DISCLAIMER

OMEGA ENGINEERING, INC. warrants this unit to be free of defects in materials and workmanship for a period of 13 months from
date of purchase. OMEGA’s WARRANTY adds an additional one (1) month grace period to the normal one (1) year product
warranty to cover handling and shipping time. This ensures that OMEGA’s customers receive maximum coverage on each
product.

If the unit malfunctions, it must be returned to the factory for evaluation. OMEGA’s Customer Service Department will issue an
Authorized Return (AR) number immediately upon phone or written request. Upon examination by OMEGA, if the unit is found to be
defective, it will be repaired or replaced at no charge. OMEGA’s WARRANTY does not apply to defects resulting from any action of the
purchaser, including but not limited to mishandling, improper interfacing, operation outside of design limits, improper repair, or
unauthorized modification. This WARRANTY is VOID if the unit shows evidence of having been tampered with or shows evidence of
having been damaged as a result of excessive corrosion; or current, heat, moisture or vibration; improper specification;
misapplication; misuse or other operating conditions outside of OMEGA’s control. Components in which wear is not warranted,
include but are not limited to contact points, fuses, and triacs.

OMEGA is pleased to offer suggestions on the use of its various products. However, OMEGA neither assumes responsibility
for any omissions or errors nor assumes liability for any damages that result from the use of its products in accordance with
information provided by OMEGA, either verbal or written. OMEGA warrants only that the parts manufactured by the
company will be as specified and free of defects. OMEGA MAKES NO OTHER WARRANTIES OR REPRESENTATIONS OF ANY
KIND WHATSOEVER, EXPRESSED OR IMPLIED, EXCEPT THAT OF TITLE, AND ALL IMPLIED WARRANTIES INCLUDING ANY
WARRANTY OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE HEREBY DISCLAIMED. LIMITATION
OF LIABILITY: The remedies of purchaser set forth herein are exclusive, and the total liability of OMEGA with respect to this
order, whether based on contract, warranty, negligence, indemnification, strict liability or otherwise, shall not exceed the
purchase price of the component upon which liability is based. In no event shall OMEGA be liable for consequential,
incidental or special damages.

CONDITIONS: Equipment sold by OMEGA is not intended to be used, nor shall it be used: (1) as a “Basic Component” under 10 CFR
21 (NRC), used in or with any nuclear installation or activity; or (2) in medical applications or used on humans. Should any Product(s)
be used in or with any nuclear installation or activity, medical application, used on humans, or misused in any way, OMEGA assumes
no responsibility as set forth in our basic WARRANTY/DISCLAIMER language, and, additionally, purchaser will indemnify OMEGA and
hold OMEGA harmless from any liability or damage whatsoever arising out of the use of the Product(s) in such a manner.

RETURN REQUESTS / INQUIRIES

Direct all warranty and repair requests/inquiries to the OMEGA Customer Service Department. BEFORE RETURNING ANY
PRODUCT(S) TO OMEGA, PURCHASER MUST OBTAIN AN AUTHORIZED RETURN (AR) NUMBER FROM OMEGA’S CUSTOMER
SERVICE DEPARTMENT (IN ORDER TO AVOID PROCESSING DELAYS). The assigned AR number should then be marked on the
outside of the return package and on any correspondence.

The purchaser is responsible for shipping charges, freight, insurance and proper packaging to prevent breakage in transit.

FOR WARRANTY RETURNS, please have the following informa­tion available BEFORE contacting OMEGA:

1. Purchase Order number under which the product was
PURCHASED,

2. Model and serial number of the product under warranty, and

3. Repair instructions and/or specific problems relative to the
product.

FOR NON-WARRANTY REPAIRS,

consult OMEGA for cur­rent repair charges. Have the following information avail­able BEFORE contacting OMEGA:

1. Purchase Order number to cover the COST of the repair,

2. Model and serial number of the product, and

3. Repair instructions and/or specific problems relative to

the product.

OMEGA’s policy is to make running changes, not model changes, whenever an improvement is possible. This affords our customers the latest in
technology and engineering.

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© Copyright 2005 OMEGA ENGINEERING, INC. All rights reserved. This document may not be copied, photocopied, reproduced, translated, or

reduced to any electronic medium or machine-readable form, in whole or in part, without the prior written consent of OMEGA ENGINEERING, INC.