Omega Products OM-CP-Bridge120 Installation Manual

650-467-8671

OM-CP-Bridge120

Bridge/Strain Gauge

Data Logger

GageFactor

R

R

ainsmi

000,000,1

)(crostr

×











∆

=µε

µε397

1.2

000,000,1

120

1.0

=

×











OM-CP-Bridge120

Product Notes

The OM-CP- Bridge120 data logger is designed to interface with and measure strain gauges and load
cells. The device provides an excitation voltage of 2.5V’s and is available in the following millivolt input
ranges: ±10mV, ±25mV, ±100mV, ±1000mV. The Bridge120 features a
sampling rate of up to 20Hz.

LEDs

Once started, the LED will flash at the selected reading rate to indicate the device is running.

Wheatstone Bridge Configuration

If it is desired to make strain gage measurements with better signal integrity and not requiring
matching the thermal expansion coefficient to the material, then a Wheatstone Bridge configuration
ought to be considered. While there are several versions of the Wheatstone Bridge, the least complex
configuration that has these desirable qualities is the One-half bridge.

ONE-HALF WHEATSTONE BRIDGE

Note 1: The two strain gages need to bend in the opposite direction when stressed. Under this arrangement, the non-linear error
is nulled out and temperature coefficients between the sensors and the material do not have to match.

Note 2: The tolerance of the 120Ω resistors and the “matched” values of the strain gages affect the “null”
reading which theoretically ought to be 0V. It is recommended to use 1% or better resistors and identical strain gages.

EXAMPLE:

A common unit of strain gage measurement is microstrains (μ). Microstrain is mathematically
expressed as such: Where R/R is the ratio between the change in strain gage resistance (under stress)
and the nominal strain gage resistance. The Gage Factor (GF) is specified by the manufacturer or
vendor of the particular gage. Typically, GF values are 2 to 4.5 for metal and 50 to 200 for
semiconductor strain gages. A 120Ω strain gage measures, under stress, 120.1Ω. The GF is 2,1.
Convert to microstrains:

GF

V

v

nsmicrostrai

p

000,000,1

2

)(

×















∆×

=µε

Quick Start Manual

If you wish to convert to microstrains from the differential bridge voltage, you can use the
following equation (assumes you are using the one-half Wheatstone Bridge as shown previously)

Where:
V = measured differential bridge voltage
Vp = bridge excitation voltage
GF = Gage Factor provided by the gage manufacturer

In some circumstances you may wish to plug in a packaged Wheatstone Bridge sensor such as
the Omega® PX170 differential pressure gage or Omega® LCGC series Load Cell gages. In these
circumstances, the internal resistive bridge cannot be altered.

When using a packaged Bridge sensor, check the specified bridge resistance. If it is less than 1kΩ then
add a 1kΩ resistor between the power and bridge. You may use values higher than 1kΩ to conserve
battery power, but it will diminish the signal to noise ratio. If the bridge resistance is greater than 1kΩ
then no additional resistor is required.

PACKAGED WHEATSTONE BRIDGE SENSOR LESS THAN 1KΩ RESISTANCE

PACKAGED WHEATSTONE BRIDGE SENSOR GREATER THAN 1KΩ RESISTANCE

OM-CP-Bridge120

Installation Guide

Installing the Interface cable

- OM-CP-IFC200
Insert the device into a USB port. The drivers will install automatically.

- OM-CP-IFC110
Plug the serial cable into the port and verify it is secure.

Installing the software

Insert the Software CD in the CD-ROM Drive. If the autorun does not appear, locate the drive on the
computer and double click on Autorun.exe. Follow the onscreen instructions.

Connecting the data logger

- Once the software is installed and running, plug the interface cable into the data logger.

- Click the Communication Menu, then Auto Configure Port.

- After a moment, a box will appear stating a device has been found.

- Click OK. The Device Status box will appear. Click OK.

- At this point, communications have been configured for your logger. These settings can be found
under the Communication Menu.

Device Operation

Starting the data logger

- Click Device Menu then Start Device.

- Choose the desired start method.

- Choose the start parameters by selecting a Reading Rate suitable for your application.

- Enter in any other desired parameters and click Start.

- A box will appear stating the data logger has been started. Click OK.

- Disconnect the data logger from the interface cable and place it in the environment.

Downloading data from a data logger

- Connect the data logger to the interface cable.

- Click the Device Menu then Read Device Data. This will offload recorded data onto the PC.

Part Number OM-CP-Bridge120

Range

Resolution

See Table Below*

Accuracy

Memory 32,767

Sample Rate 20Hz to 12 hours

Units

V, mV, μV, Engineering Units specied through software

Required Interface Package OM-CP-IFC110 or OM-CP-IFC200

Baud rate 57,600

Typical Battery Life 25 days

Operating Environment –40°C to +80°C (-40°F to 176°F),

0%RH to 95%RH (non-condensing)

Material ABS plastic

Dimensions 0.8” x 1.7” x 2.7” (20mm x 43mm x 69mm)

Approvals CE Pending

Nominal Range +10mV +25mV +100mV +1000mV

Measurement Range +15mV +37.5mV +120mV +1200mV

Resolution 1µV 2.5µV 5µV 50µV

Accuracy +0.25%FSR +0.10%FSR +0.05%FSR +0.01%FSR

Input Range 0 to 2.5V 0 to 2.5V 0 to 2.5V 0 to 2.5V

Reference Voltage 2.5V 2.5V 2.5V 2.5V

Battery Warning

WARNING: FIRE, EXPLOSION, AND SEVERE BURN HAZARD. DO NOT SHORT
CIRCUIT, CHARGE, FORCE OVER DISCHARGE, DISASSEMBLE, CRUSH, PENETRATE
OR INCINERATE. BATTERY MAY LEAK OR EXPLODE IF HEATED ABOVE 80˚C (176˚F).

OMEGAnet

Servicing North America:

U.S.A.:

Omega Engineering, Inc., One Omega Drive, P.O. Box 4047

Stamford, CT 06907-0047

Toll-Free: 1-800-826-6342 Tel: [phone]
FAX: [phone] e-mail: [e-mail]

Canada:

976 Bergar

Laval (Quebec), H7L 5A1 Canada
Toll-Free: 1-800-826-6342 TEL: [phone]
FAX: [phone] e-mail: [e-mail]

For immediate technical or application assistance:

U.S.A. and

Canada: Customer Service: 1-800-622-2378/1-800-622-BEST

Mexico/
Latin America

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.

Sales Service: 1-800-826-6342/1-800-TC-OMEGA

Engineering Service: 1-800-872-9436/1-800-USA-WHEN

En Español: 001 [phone] FAX: [phone]

[e-mail] e-mail:[e-mail]

®

Online Service Internet e-mail

omega.com [e-mail]

Servicing Europe:

Benelux:

Toll-Free: 0800 099 3344 TEL: [phone]
FAX: [phone] e-mail: [e-mail]

Czech
Republic:

Toll-Free: 0800-1-66342 TEL: [phone]
FAX: [phone] e-mail: [e-mail]

France: Managed by the United Kingdom Office

Toll-Free: 0800 466 342 TEL: [phone]
FAX: [phone] e-mail: [e-mail]

®

®

Germany/
Austria

®

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

United
Kingdom: One Omega Drive, River Bend Technology Centre, Northbank

ISO 9001

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

Managed by the United Kingdom Office

Frystatska 184

733 01 Karviná, Czech Republic

Daimlerstrasse 26, D-75392 Deckenpfronn, Germany

Toll-Free: 0800 6397678 TEL: [phone]

OMEGA Engineering Ltd.

Irlam, Manchester M44 5BD United Kingdom

Toll-Free: 0800-488-488 TEL: [phone]

WARRANTY/DISCLAIMER

OMEGA ENGINEERING, INC. warrants this unit to be free of defects in materials and workmanship for a period of 61 months from
date of purchase. OMEGA’s WARRANTY adds an additional one (1) month grace period to the normal five (5) 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’sCustomer 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’sWARRANTY 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’scontrol. 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 OMEGAis not intended to be used, nor shall it be used: (1) as a “Basic
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, OMEGAassumes
no responsibility as set forth in our basic WARRANTY/ DISCLAIMER language, and, additionally, purchaser will indemnify OMEGAand
hold OMEGAharmless from any liability or damage whatsoever arising out of the use of the Product(s) in such a manner.

Component” under 10 CFR

Direct all warranty and repair requests/inquiries to the OMEGA Customer Service Department. BEFORE RETURNING ANY

RETURN REQUESTS /INQUIRIES

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
tion 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.

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.
OMEGA is a registered trademark of OMEGA ENGINEERING, INC.
© Copyright 2011 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.

RETURNS, please have the following informa-

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.

MQS-5035/1011

MQS-5044/0412