Omega DMD-476 User's Guide

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Omega DMD-476 User's Guide | Manualzz

User’s Guide

®

An OMEGA Technologies Company

http://www.omega.com

e-mail:[email protected]

DMD-476 Bridgesensor

AC Powered Signal Conditioner

2

omega.com

®

® http://www .omega.com

ISO 9001 Certified

Servicing North America:

One Omega Drive, Box 4047

Stamford, CT 06907-0047

Tel: (203) 359-1660 e-mail: [email protected]

FAX: (203) 359-7700

976 Bergar

Laval (Quebec) H7L 5A1

Tel: (514) 856-6928 e-mail: [email protected]

FAX: (514) 856-6886

For immediate technical or application assistance:

USA and Canada: Sales Service: 1-800-826-6342 / 1-800-TC-OMEGASM

Customer Service: 1-800-622-2378 / 1-800-622-BESTSM

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

TELEX: 996404 EASYLINK: 62968934 CABLE: OMEGA

Tel: (95) 800-826-6342

En Español: (95) 203-359-7803

Servicing Europe:

FAX: (95) 203-359-7807 e-mail: [email protected]

Postbus 8034, 1180 LA Amstelveen, The Netherlands

Tel: (31) 20 6418405

Toll Free in Benelux: 0800 0993344 e-mail: [email protected]

FAX: (31) 20 6434643 ul. Rude armady 1868, 733 01 Karvina-Hranice

Tel: 420 (69) 6311899

Toll Free: 0800-1-66342 e-mail: [email protected]

FAX: 420 (69) 6311114

9, rue Denis Papin, 78190 Trappes

Tel: (33) 130-621-400

Toll Free in France: 0800-4-06342 e-mail: [email protected]

FAX: (33) 130-699-120

Germany/Austria: Daimlerstrasse 26, D-75392 Deckenpfronn, Germany

Tel: 49 (07056) 3017

Toll Free in Germany: 0130 11 21 66 e-mail: [email protected]

FAX: 49 (07056) 8540

United Kingdom: One Omega Drive, River Bend Technology Centre

ISO 9002 Certified Northbank, Irlam, Manchester

M44 5EX, England

Tel: 44 (161) 777-6611 FAX: 44 (161) 777-6622

Toll Free in the United Kingdom: 0800-488-488 e-mail: [email protected]

It is the policy of OMEGA 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 Engineering, Inc. accepts no liability for any errors it contains, and reserves the right to alter specifications without notice.

W ARNING : These products are not designed for use in, and should not be used for, patient-connected applications.

Description

The Model DMD-476 is a self contained, AC powered signal conditioner for bridge type instrumentation. It contains a precision instrumentation amplifier with isolated, filtered output and a highly regulated, low noise, adjustable output bridge excitation source. The unit is completely encapsulated for use in rugged environments.

Features n Complete Strain Gage

Bridge Signal Conditioner n Isolated 4-20 mA or 0-20 mA Output n Output Capable of Driving 1000 ohm Loop n Bridge Balance with 80%

Tare Offset Capability n High Gain Amplifier; Can Accept Full Scale

Live Load Signals as Low as 5 mV and

Provide 16 mA Output Span n Excitation Supply Capable of Driving

Four Load Cells n AC Powered n Rugged Epoxy Encapsulated Design

Applications n Weighing with Load Cells n Process Control Add-on Loops n Can Be Used With All Types of

Low Output Sensors

Specifications

NOTE: Unless otherwise noted, specifications apply after one hour warm up at 25°C ambient. Temperature coefficients apply between

0°C and 55°C ambient.

I s o l a t i o n

I n p u t t o O u t p u t

7 0 0 V D C

6 0 p F

A m p l i f i e r

G a i n

A d j u s t m e n t

I n p u t f o r 4 -

R a n g e

2 0 m A O u t p u t

L i n e a r i t y

T e m p e r a t u r e S t a b i il t y

I n p u t N o i s e

5 m V t o

±

0 .

0 1 %

5 o f

0

F m u

V ll S c a l e

5 0 P P M ( 0 .

0 0 5 % /

°

C )

.

1 H z t o 1 0 H z

T a r e A d j u s t m e n t R a n g e

2 V P P

B r i d g e O f f s e t

3 m V

( E q u a l s t o + 2 5

8 0 % m V

F .

S .

3 m V / V c e ll ) o f

I n p u t R e s i s t a n c e

D i f f e r e n t i a l a n d C o m m o n M o d e 1 0 0 0 m e g o h m

C o m m o n M o d e R e j e c t i o n , D C

C o m m o n M o d e I n p u t

1 0 0 d B m i n i m u m

+ 5 V o l t s

O u t p u t

Z e r o A d j u s t

T e m p e r a t u r e C o e f f i c i e n t

C u r r e n t O u t p u t S p a n

C o m p il a n c e V o l t a g e

C u r r e

L o o p n t

R e s i s t a n c e

F r e q u e n c y R e s p o n s e , 3 d B

R e s p o n s e T i m e

R i

T o s e

0 .

T i

1 m

% e o f

1 0 %

F i n a l t o

V

9 a l

0 % u e

B r i d g e S u p p l y

V o l t a g e A d j u s t m e n t R a n g e

0

1 m

A / C

4 t o 2 0

1 t o

3 5 o

1 0 0 r 4 m A m s m s m A o r 0 t o 2 0 m A

+ 2 0 V o l t s

1 m A t o + 2 0 m A

0 t o 1 0 0 0 o h m s

1 0 H e r t z , 2 P o l e R o ll O f f

L

T

F o a d

R e g e m i x p e r a e d

T e m t u r e p e r a t u r e

C u r r e n t u l a t i o n -

O u t p u t N o i s e

C o e

C o e

L o a d f f i c i e n t f f i c i e n t a n d L i n e

5 t o 1 0 V o l t s

1 0 0 P P M T y p i c a l

1 0 .

2 V

±

2 .

5 %

6 0 P P M T y p i c a l

0 t o 1 2 0 m A

0 .

0 2 % m a x i m u m

P o

1 2 0 H z B a n d w i d t h w e r I n p u t

1 m

1 1 5

V

V

R M S

A C ,

, m a x i m u m

±

1 0 V 5 0 / 6 0

@ 7 V A

H z

1 0 0 , 2 2 0 o r 2 3 0 V A C , – 1 0 % O p t i o n a l

L i n e I s o l a t i o n

C a p a c i t a n c e

D i e l e c t r i c W i t h s t a n d

E n v i r o n m e n t

A m b i e n t O p e r a t i n g

S t o r a g e

W e i g h t

S i z e

6

1

-

-

1

0

1

8

0

2 5

2 5 p

°

°

0 o

F

C

C z .

V t t

( o l o o

5 t s

+

+

1 0

R

5

8

5

5 g

M S

°

° r

C

C a m s )

3 .

7 5 "

( 9 .

5 3

L x c m

2 .

x

0 "

5 .

1

W x c m

2 .

8 7 " x 7 .

6 2

H c m )

3

MODEL DMD-476 Block Diagram

SWB - Excitation Voltage

S W B 1

O N

O F F

E x c i t a t i o n V o l t a g e

F i x e d 1 0 V o l t s

A d j u s t a b l e

SWA - Control Switch

S W A 1

O F F

O N

S W A 2

O F F

O N

4

S W A 4

O N

O F F

O N

O F F

S W A 5

O N

O N

O F F

O F F

T a r e R a n g e

3 m V t o + 1 5 m V

+ 1 5 m V t o + 2 5 m V

Z e r o C u r r e n t

4 m A

0 m A

S p a n R a n g e

4 0 m V t o 5 0 m V

2 0 m V t o 4 0 m V

1 0 m V t o 2 0 m V

5 m V t o 1 0 m V

Mechanical Specifications

S c r e w

T e r m i n a l

1

2

3

4

5

E

-

T e r m i n a l S t r i p A s s i g n m e n t s

F u n c t i o n

X

S

C

E

I

N

T A

S

T I

E

O N

+ S E N S E

+ E X C I T A T I O N

A C

S c r e w

T e r m i n a l

6

7

1

8

9

0

F u n c t i o n

A C

+ S I G N A L

S I G N A L

O U T P U T

R E T U R N

Getting Started with the Model DMD-476

1. Excitation Supply. If remote sensing is not used, connect +Sense to +Excitation, terminal 3 to 4, and connect -Sense to -Excitation, terminal 1 to 2.

2. Apply power to the DMD-476 and adjust the Excitation supply. Turn SWB-1 “ON” for a fixed 10 Volts.

This will set the supply to 10.2 ±2.5% and provide the best temperature stability. For voltages between

5 and 10 Volts, place SWB-1 in the “OFF” position and set the Excitation Supply with potentiometer

E. SWB-2 may be in either position.

3. Turn the power to the DMD-476 off and connect the load cell to the DMD-476 Excitation terminals and the Amplifier Inputs.

4. Turn on power to the DMD-476.

5. Turn SWA-3 “ON”. (To set output ZERO current with pot D.)

6. Select the expected full scale signal range according to the table with SWA-4 and

SWA-5. If the output from the load cell is not known, set both SW-4 and

SW-5 “ON” for the 40-50mV range.

7. Set SWA-2 “OFF” for 4mA or SWA-2 “ON” for 0mA output ZERO.

8. Adjust D potentiometer for desired ZERO current.

9. Turn SWA-3 “OFF”. Expect output current to change.

10. Apply no load or dead weight to load cell.

11. Adjust TARE potentiometers A and B for the same ZERO current set in Step 8.

SWA-1 “OFF” provides a bridge output balance of -3mV to +15mV, and “ON” between +15mV and

+25mV.

12. Apply full scale load and adjust SPAN (GAIN) potentiometer C for the desired full scale output current.

Set Range switches SWA-4 and SWA-5 as required.

13. Remove full scale load and check ZERO output current. Adjust FINE TARE potentiometer A if required.

14. Recheck full scale as in Step 12.

15. End.

Note: If the amplifier is used without using the DMD-476 Excitation Supply, the external power supply low side must be connected to the -EXCITATION terminal 2 on the Model DMD-476, or one of the inputs must be tied to terminal 2, -EXCITATION. This provides a DC return path for the finite amplifier input current.

5

Amplifier

The amplifier is a true differential input, low drift Instrumentation Amplifier with less than 100pA input current. It has a common mode range of 5 Volts with respect to the - EXCITATION supply terminal and a minimum of 100dB rejection of the common mode voltage. The input amplifier and excitation supply are

DC isolated from the AC line and the current output.

The isolated output current source has a compliance of 20 Volts to allow the Model DMD-476 to operate with zero to 1000 Ohms of loop resistance.

Tare Weight Compensation

The Model DMD-476 has two different zero controls. One is called the OUTPUT zero and can be set to

0mA or 4mA with SWA-2. The other zero control is called TARE. SWA-1 allows the selection of one of two TARE ranges, -3mV to 15mV or +15mV to +25mV. Potentiometers are available for COARSE and

FINE TARE adjustments.

Connecting to a Sensor

Any amplifier has a finite input current which must have DC return path to the amplifier power supplies. This path is automatically provided when the Model DMD-476 Bridge Excitation Supply is used to excite the sensor. If an external supply is used, one side of the external supply must be connected to the DMD-476 common, Terminal 2. Be sure that the common mode voltage limits are observed. This would generally limit the external power supply to 10 Volts assuming that half the voltage would be common mode, as is the case when exciting a full bridge.

When the full scale output of a sensor is measured in millivolts, say 10 millivolts, care must be exercised in wiring systems. At 10 millivolts full scale, each microvolt (10

-6

volts) contributes 0.01% of full scale output. Wire connections can generate microvolts of potential due to contact potentials. These will also be thermoelectric potentials and thus vary with temperature differences. All wires used in connecting up the Model DMD-476 should be of the same material. If any intervening connections are made such as a terminal block, the terminal block connecting points should have good thermal contact so they will always be at the same temperature and thus cancel each other.

Transducer Excitation

The bridge excitation supply voltage is set by SWB-1 and potentiometer E. Set SWB-1 ON for a fixed 10

Volts. This will provide the best temperature stability. The supply can be adjusted between 5 and 10 Volts by setting SWB-1 OFF and adjusting potentiometer E. The supply will deliver up to 120mA current at any voltage setting to power up to four 350 ohm sensors.

6

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 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 which wear are not warranted, including but 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 it will be as specified and free of defects. OMEGA MAKES NO OTHER

WARRANTIES OR REPRESENTATIONS OF ANY KIND WHATSOEVER, EXPRESS 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 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.

OMEGA is a registered trademark of OMEGA ENGINEERING, INC.

©

Copyright 1999 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.

7

M-3241

8

Where Do I Find Everything I Need for

Process Measurement and Control?

OMEGA...Of Course!

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þ Industrial Water & Wastewater Treatment

þ pH, Conductivity & Dissolved Oxygen Instruments

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