Omega DRA-RTM-8 User Manual

User’s Guide

http://www.omega.com

e-mail: [e-mail]

DRA-RTM-8

ANALOG MULTIPLEXER

OMEGAnet

SM

http://www.omega.com

On-Line Service

omega.com

OMEGA

®

[e-mail]

TM

Internet e-mail

USA:

ISO 9001 Certified

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

Mexico and
Latin America: Tel: (95) 800-TC-OMEGASM FAX: [phone]

Benelux: Postbus 8034, 1180 LA Amstelveen, The Netherlands

Czech Republic: Ostravska 767,733 01 Karvina

France: 9, rue Denis Papin, 78190 Trappes

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

United Kingdom: 25 Swannington Road, P.O. Box 7, Omega Drive,

ISO 9002 Certified Broughton Astley, Leicestershire, Irlam, Manchester,

One Omega Drive, Box 4047
Stamford, CT 06907-0047
Tel: [phone]
FAX: [phone]
e-mail: [e-mail]

Customer Service: 1-800-622-2378 / 1-800-622-BESTSM
Engineering Service: 1-800-872-9436 / 1-800-USA-WHENS M
TELEX: 996404 EASYLINK: 62968934 CABLE: OMEGA

En Espanol: (95) 203 359-7803 e-mail: [e-mail]

Tel: [phone] FAX: [phone]
Toll Free in Benelux: 06 0993344
e-mail: [e-mail]

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

Tel: [phone] FAX: [phone]
Toll Free in France: 0800-4-06342
e-mail: [e-mail]

Tel: [phone] FAX: [phone]
Toll Free in Germany: 0130 11 21 66
e-mail: [e-mail]

LE9 6TU, England M44 5EX, England
Tel: [phone] Tel: [phone]
FAX: [phone] FAX: [phone]
Toll Free in England: 0800-488-488
e-mail: [e-mail]

Canada:

976 Bergar
Laval (Quebec) H7L 5A1
Tel: [phone]
FAX: [phone]
e-mail: [e-mail]

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

Contents

1. GENERAL DESCRIPTION

2. MOUNTING INSTRUCTIONS

3. REPLACING FUSES

4. ASSEMBLY

5. CURRENT INPUTS

6. CONNECTING TRANSMITTERS TO THE MULTIPLEXER

7. CONNECTING Pt-100 TO THE MULTIPLEXER

8. CONNECTING THE MULTIPLEXER TO A PLC

9. CONTROL

9.1 Enable

9.2 Address

9.3 Address Polarity

9.4 Control Tables

10. CALIBRATION

10.1 Calibration Procedure

10.2 Calibration Tables

10.2.1 "ZERO" - Coarse Calibration Tables

10.2.2 "SPAN" - Coarse Calibration Tables

11. MULTIDROP CONFIGURATION

12. SPECIFICATIONS

1

1. GENERAL DESCRIPTION

The DRA-RTM-8 is a multiplexer for 16 analog inputs - eight of which, marked
1-8, are direct inputs for Pt-100 sensors, while the remaining (9-16), are for 4­20mA current loops.
The DRA-RTM-8 output format is a 4-20mA current loop, with a 28mA limitation.

Each Pt-100 input has its own signal conditioner, allowing each input to be
calibrated separately. Each signal conditioner includes six DIP switches for coarse
calibration and two potentiometers for fine tuning.

2. MOUNTING INSTRUCTIONS

The DRA-RTM-8 is designed for standard DIN rail mounting.
Place the unit on the upper part of the mounting rail with the fastening tab facing

down. Using a suitable flat screwdriver loosen the tab slightly and attach the unit
to the rail. Once the tab is loosened, ensure that the unit is fastened securely in
place.

3. REPLACING FUSES

To replace a blown fuse, disassemble the unit as follows:
a. Take off both terminal strips by removing the four screws at the edges.

Note: This does not require disconnecting the cables connected to the strips.

b. Remove the front panel using a suitable flat screwdriver. Press down gently on
the plastic springloaded tabs located in the slots on either side of the unit.
c. Disconnect the flat connectors which connects the front panel printed circuit.
d. Replace the blown fuse.

WARNING: Never install a fuse rated more than 800mA

4. ASSEMBLY

The DRA-RTM-8 unit includes two printed circuit cards designated as P.N 7020
and P.N 7021. The two printed circuit cards should occupy the slots in the
enclosure according to fig 1.

2

Insert the two printed cards into their slots.
Connect the flat cable between them.
Connect the front panel flat cables. The
panel must be inserted into the grooves on
both sides of the case while pressing down
until a distinct "click" is heard. Assembly is
completed by laying the terminal strips in
place.

Figure 1.

Note: The terminal strips are polarized and must not be placed backwards.

5. CURRENT INPUTS

The eight 4-20mA current inputs are marked as channels 9-16. These inputs are
for current only. The "COM" input is the return for all the current channels. It is
possible to connect any current source, as long as a closed loop is maintained.

WARNING: Voltage sources should not be connected to the current
inputs,as permanent damage might occur.

6. CONNECTING TRANSMITTERS TO THE MULTIPLEXER

6.1 TWO WIRE TRANSMITTER

A Two-Wire transmitter is connected so that its
positive terminal is connected to the positive
terminal of the power supply, and its negative
terminal is connected to the "I" terminal.
(see fig 2)

Figure 2.

6.2 FOUR WIRE TRANSMITTER

A Four-Wire transmitter is connected so that its
positive terminal is connected to the "I" terminal,
and its negative terminal is connected to the
"COM" terminal. (see fig 3)

Figure 3.

3

7. CONNECTING Pt-100 TO THE MULTIPLEXER

The Pt-100 probe should be connected according to fig 4. The
three wires connecting the probe should be identical.
The distance of the probe can be up to 200 meters.
A shielded cable is recommended.
The shield should be grounded at one point. When possible,
connect the ground at the multiplexer's end.

Figure 4.

8. CONNECTING THE DRA-RTM-8 TO A PLC

The multiplexer output should be connected to 4-20mA input of the PLC analog
module (see fig 5).
The DRA-RTM-8 multiplexer generates the output current, therefore the PLC analog
module should be configured for four wire transmitter connection.

WARNING: NEVER apply 24Vdc to the DRA-RTM-8's +Io terminal
as in two-wire connection, and make sure that the PLC's
analog module is configured as a passive input.

9. CONTROL

The DRA-RTM-8 unit is controlled via four
address lines and one E (Enable) line.
The control terminals (Address and
Enable), were designed to receive control
signals from TTL levels up to 60V so that
almost any PLC's DC output module can
be used. (see fig 5)

Figure 5.

9.1 ENABLE

The unit is enabled when a logical "1" (5V < E < 60V) is connected to the E
Terminal. In a disabled state, the DRA-RTM-8 outputs no current and reflects a
Hi-Z state. This feature allows the connection of several DRA-RTM-8 units by tying
their outputs and control in parallel and addressing them by controlling the
individual Enable terminals.

4

9.2 ADDRESS

The required channel is selected by
four address lines.
The operating voltages are:

Logical "1" 5V < Vi < 60V
Logical "0" 0V < Vi< 0.5V

9.3 ADDRESS POLARITY (see fig 6)

Figure 6.

Address polarity is controlled by three internal pins and a jumper over two of them,
located on PN 7021 printed circuit board, accessible behind the Enable terminal.
The unit is supplied with the jumper set for "true high" control logic, i.e. "0000"
selects channel #1, and "1111" selects channel #16.
Moving the jumper to the second alternative, reverses the logic.

Note: If the address contros voltages are generated from different power
supplies, then its negative terminal should be connected to the
DRA-TM-8's "COM" terminal.

9.4 CONTROL TABLES

9.4.1 "TRUE LOW" SETTING

ADDRESS BUS

A3

0

0

0

0

0

0

1

0

0

1

0

0

0

1

0

0

1

0

1

1

0

1

1

0

x

x

x

OUTPUT

E
1

1
1
1
1
1
1
1

NO OUTPUT

0

CHANNEL

16
15
14
13
12
11
10

9

A0A1A2

0
1
0
1
0
1
0
1
x

ADDRESS BUS

A3

0

0

1

0

0

1

1

0

1

1

0

1

0

1

1

0

1

1

1

1

1

1

1

1

x

x

x

OUTPUT

E
1

1
1
1
1

1
1
1
0

CHANNEL

8
7
6
5
4
3
2
1

NO OUTPUT

A0A1A2

0
1
0
1
0
1
0
1
x

5

9.4.2 "TRUE HIGH" SETTING

ADDRESS BUS

A3

0
0
0
0
0
0
0
0
x

0

0

0

0

1

0

1

0

0

1

0

1

1

1

1

1

x

x

OUTPUT

E/T

1
1
1
1
1
1
1
1
0

CHANNEL

1
2
3
4
5
6
7
8

TEST MODE

A0A1A2

0
1
0
1
0
1
0
1
x

ADDRESS BUS

A3

0

0

1

0

0

1

1

0

1

1

0

1

0

1

1

0

1

1

1

1

1

1

1

1

x

x

x

OUTPUT

E/T

1
1
1
1
1
1
1
1
0

CHANNEL

9
10
11
12
13
14
15
16

TEST MODE

A0A1A2

0
1
0
1
0
1
0
1
x

Note: The unit includes three internal potentiometers. These potentiometers
are carefully adjusted and sealed in the factory . It is not recommended
to alter these calibration potentiometers.

10. CALIBRATION

To calibrate the DRA-RTM-8, the limits must be defined.
Tmin is the temperature at which the output current is 4mA.
Tmax is the temperature at which the output current is 20mA.
Tspan is the difference between Tmax and Tmin.

10.1 CALIBRATION PROCEDURE

a. Remove the terminal strips to get access to the coarse calibration switches.
b. Set the channels DIP switches to the desired calibration ranges according to the

calibration tables.
c. Re-install the terminals strips. The terminal strips are polarized and should be

returned to their original position.
d. Connect a Pt-100 calibrator* set for Tmin to the proper input terminals.
e. Apply the proper channel selection code by connecting those which according

the table should be "1" to the +PWR terminal.
f. Start calibrating by adjusting the proper "Z" potentiometer to obtain an output

current of 4.000mA.
g. Set the calibrator for Tmax and adjust the "S" potentiometer to obtain an output

current of 20.000mA.
h. Repeat this procedure until satisfactory results are obtained.

6

i. Change the address to the next channel to be calibrated.
j. Repeat steps b to h

* The calibrator is set according to DIN 43760 Pt-100 table (a = 0.00385)

10.2 CALIBRATION TABLES

Note: Logic state of "0" is when the DIP switch lever is down.

10.2.1 "ZERO" - COARSE CALIBRATION TABLES

CHANNELS 1-4

ZERO TEMP OC

-50.....10

8.....75

74...140

139...206

205...272

270...338

336...404

401...470

SW6

SW5

1

1
1

0
1
0

1

1

1

0
1

0

00

SW4

1
1

0

1
1

0

0
0
0
0

10.2.2 "SPAN" - COARSE CALIBRATION TABLES

CHANNELS 1-4

SPAN OC

50.....76

65...115

110...180

135...225

215...440

400...800

SW1

1
1
0

001
0

SW2

1
0

1

0
0

SW3

1
1
1
0
1
0

CHANNELS 5-8

SW1

SW2

SW3

1

1

0

1

1

0

0

0

1

1
0

1

0

1
00

CHANNELS 5-8

SW6

1
1

0
001
0

SW5

1
0

1

0
0

SW4

1
1

1
1

0
0
0
0

1
1
1

0
1

0

7

11. MULTIDROP CONFIGURATION

In the disabled state (E=0), the multiplexer outputs no current and exhibits a high
Z state. This mode allows the connection of several DRA-RTM-8 units to one PLC's
analog input, by tying their output terminals and the address lines in parallel, and
applying individual Enable lines to select the desired multiplexer by disabling all
but one (see fig 7).

ANALOG +
ANALOG -

PLC

ANALOG

INPUT

MODULE

ENABLE 1
ENABLE 2

MSB

DISCRETE

OUTPUT

LSB

MODULE

Figure 7.

12. SPECIFICATIONS

ANALOG INPUTS:
RTD INPUT:

Zero adjustability:
Span adjustability:
Lead Compensation Error:
Max Lead Resistance:
Pt-100 linearization:

CURRENT INPUT
Max Input Current:
Reverse Polarity Protection:
Output Accuracy (Refer to Current Input):

CONTROL INPUTS:
Logic:

Logic Levels:
OUTPUT:
SWITCHING TIME:
INDICATORS:

SUPPLY VOLTAGE:
SUPPLY CURRENT CONSUMPTION:
FUSE:
TEMPERATURE STABILITY:
OPERATING TEMPERATURE:
STORAGE TEMPERATURE:
HUMIDITY:
HOUSING:

Box:
Terminal:

WEIGHT:
DIMENSIONS:

8, Pt-100 Channels
8, 0/4-20mA Channels

50 to +200
50 to 750

0.025

oC for 10W lead resistance

120Wtwo ways

0.1% of span max.
30 mA

Yes

0.1% of span max.
4 Address

1 Enable input
True High or True Low (User selectable)
Low: "0" < 0.5V High: 5 < "1" < 60V

4-20mA, Current Loop

m

Sec (into a resistive load)

< 20
1 Yellow LED, Power-On indicator

8 Red LEDs, current activity indicators
24 10% Vdc (regulated)
120 mA 10mA
150 mA, Fast Blow (5x20mm)

0.01% of span/1
oC (32 to 140

0 to 60

-25 to +85

5 to 95% Relative humidity, non-condensing
Plastic Polycarbonate

According to IP50 DIN 40050
According to IP20 DIN 40050

0.9 Kg. (2.0 lb.)

73Hx200Wx121mmD (2.88"x7.88"x4.76")

a

=0.00385

oC

oC

oC

oF)

oC (-13 to 185

oF)

8

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 should malfunction,
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 being 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, 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.

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. P.O. 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 1996 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 prior written consent of OMEGA ENGINEERING, INC.

WARRANTY/DISCLAIMER

RETURN REQUESTS / INQUIRIES

FOR NON-WARRANTY REPAIRS, consult
OMEGA for current repair charges. Have the
following information available BEFORE
contacting OMEGA:

1. P.O. 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.

Where Do I Find Everything I Need for

Process Measurement and Control?

OMEGA…Of Course!

TEMPERATURE

⻬ Thermocouple, RTD & Thermistor Probes,
Connectors, Panels & Assemblies

⻬ Wire: Thermocouple, RTD & Thermistor
⻬ Calibrators & Ice Point References
⻬ Recorders, Controllers & Process Monitors
⻬ Infrared Pyrometers

PRESSURE, STRAIN AND FORCE

⻬ Transducers & Strain Gauges
⻬ Load Cells & Pressure Gauges
⻬ Displacement Transducers
⻬ Instrumentation & Accessories

FLOW/LEVEL

⻬ Rotameters, Gas Mass Flowmeters & Flow Computers
⻬ Air Velocity Indicators
⻬ Turbine/Paddlewheel Systems
⻬ Totalizers & Batch Controllers

pH/CONDUCTIVITY

⻬ pH Electrodes, Testers & Accessories
⻬ Benchtop/Laboratory Meters
⻬ Controllers, Calibrators, Simulators & Pumps
⻬ Industrial pH & Conductivity Equipment

DATA ACQUISITION

⻬ Data Acquisition & Engineering Software
⻬ Communications-Based Acquisition Systems
⻬ Plug-in Cards for Apple, IBM & Compatibles
⻬ Datalogging Systems
⻬ Recorders, Printers & Plotters

HEATERS

⻬ Heating Cable
⻬ Cartridge & Strip Heaters
⻬ Immersion & Band Heaters
⻬ Flexible Heaters
⻬ Laboratory Heaters

ENVIRONMENTAL
MONITORING AND CONTROL

⻬ Metering & Control Instrumentation
⻬ Refractometers
⻬ Pumps & Tubing
⻬ Air, Soil & Water Monitors
⻬ Industrial Water & Wastewater Treatment
⻬ pH, Conductivity & Dissolved Oxygen Instruments

M2614/0197