Omega TX93A User manual

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TX93A
(J, K, T, E) 4-20 mA
Ultra-Miniature
Temperature Transmitters
TM
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omega.com
User’s Guide

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.
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TABLE OF CONTENTS
Section 1 Getting Started
1.1 Unpacking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
1.2 Safety and EMC Considerations . . . . . . . . . . . . . . . . . . .1
1.3 General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
1.4 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
1.5 Models Available . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Section 2 Installation
2.1 Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
2.2 Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Section 3 Calibration Instructions
3.1 Equipment Required . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
3.2 Set-up of Equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
3.3 Calibration Procedures. . . . . . . . . . . . . . . . . . . . . . . . . . .8
Section 4 Troubleshooting Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Section 5 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

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FIGURES & TABLES
Figure 1-1 Thermocouple Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Figure 1-2 Straight Line Approximation of a Curve . . . . . . . . . . . . . . . . .3
Figure 2-1 Assembly inside an NB2 Protection Head . . . . . . . . . . . . . . .5
Figure 2-2 Wiring Diagram for Thermocouple Transmitter . . . . . . . . . . .6
Figure 3-1 Transmitter Calibration Set-Up . . . . . . . . . . . . . . . . . . . . . . . .9
Figure 3-2 Transmitter Calibration Set- Up (Alternate) . . . . . . . . . . . . . .9
Figure 5-1 Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Table 1-1 Range Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Table 1-2 Model Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Table 3-1 Calibration Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

1.1 Unpacking
Remove the packing list and verify that you have received all equipment. If
you have any questions, contact the nearest Customer Service
Department, as listed on the cover of this manual.
Upon receipt of shipment, inspect the container and equipment for any
signs of damage. Note any evidence of rough handling in transit.
Immediately report any damage to the shipping agent.
Note: The carrier will not honor any claims unless all shipping
material is saved for their examination. After examining and
removing contents, save packing materials and carton in the event
reshipment is necessary.
1.2 Safety and EMC Considerations
This instrument is a Class III device (8 to 35 Vdc).
Always use a power supply, which complies with EN 60950 safety
standard.
•Do not expose the transmitter to rain or condensing moisture.
•Do not operate the transmitter in flammable or explosive atmosphere.
•As with any electronic instrument, you may encounter high voltage
exposure when installing, calibrating or removing parts of the
transmitter.
EMC Considerations
•Whenever EMC is an issue, always use shielded cables.
•Never run signal and power wires in the same conduit.
•Use signal wire connections with twisted-pair cables.
•Install Ferrite Bead(s) on signal wires close to the instrument if EMC
problems persist.
Failure to follow all instructions and warnings may result in injury!
1.3 General Description
The Thermocouple Two-Wire Temperature Transmitter accepts
thermocouple sensor types J, K, T, or E and will produce a standard 4-
20mA output signal proportional to that produced by its attached input
temperature sensor. Transmission of the proportional current output may
be accomplished by using inexpensive copper wire.
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2
1.3 General Description (continued)
The transmitter is normally powered by an unregulated power supply as
shown in Figure 1-1. The proportionally-transmitted signal begins at 4mA,
at the low end of its temperature range, and increases to 20mA, at the
high end of its temperature range. (There are various temperature ranges/
thermocouple types available for the transmitter. To order, refer to Section
1.5 for correct Model Numbers and Range Codes.)
Figure 1-1 Thermocouple Transmitter
The two-wire transmitter receives and measures signals from
themocouples and sends an output current of 4-20mA which is directly
proportional to the thermocouple millivolt input. It is designed to connect
with only two copper wire leads that will supply the voltage to operate the
transmitter from a power supply, and also carry the output current. The
output current is used for recording, computing, or controlling.
If the transmitter is mounted inside a protection head, (see Figure 2-1), the
thermocouple extension wires are replaced by two copper wires that carry
the 4-20mA signal and dc voltage to operate the transmitter.
The transmitter has reverse supply polarity protection and will operate with
a wide range of supply voltages (8 to 35 Vdc). It has an input sensor break
protection circuit that forces the output current to go upscale when the
thermocouple wire opens.
The transmitter does NOT provide isolation between its input and the
4-20 mA output; therefore, an ungrounded thermocouple junction is
suggested to prevent possible ground loops.

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1.3 General Description (continued)
Most thermocouple transmitters with 4-20 mA outputs, including this
transmitter , are proportional with respect to the thermocouple input
voltage. However, the relationship between temperature and millivolt
for all the thermocouple types is somewhat non-linear.
This leads to maximum error at approximately the midpoint of the
range as shown in Figure 1-2.
Figure 1-2 Straight Line Approximation of a Curve
1.4 Features
• 4-20 mA output
• +/-0.1% full-scale accuracy (with respect to the mV input signal)
• Upscale break protection
• Low Cost
RANGE
T/C CURVE
LINEARITY
ERROR
STRAIGHT LINE
INCREASING TEMPERATURE
INCREASING MILLIVOLTS

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1.5 Models Available
Table 1-1 Range Code
INPUT TYPES
RANGE J K T E
-40 to 120 F (-40 to 49 C) J1 - - E1
0 to 200 F (-18 to 93 C) J2 K2 T2 E2
0 to 300 F (-18 to 149 C) J3 K3 T3 E3
0 to 500 F (-18 to 260 C) J4 K4 T4 E4
0 to 750 F (-18 to 399 C) J5 K5 T5 E5
0 to 1000 F (-18 to 538 C) J6 K6 - E6
Table 1-2 Model Numbers
Model Number Description
TX93A-(*) Thermocouple Transmitter (J, K, T, or E)
NB2TX93A-(*) NB2 thermocouple probe, 12"L, 1/4” O.D.,
ungrounded junction, 304SS sheath
*Insert range code from Table 1-1

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2.1 Mounting
The transmitter may be:
1. surface mounted
2. mounted inside a protection head (shown in Figure 2-1)
Figure 2-1 Assembly of the Transmitter
inside an NB2 Protection Head
SECTION A-A
POWER LINES
T/C WIRES

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2.2 Wiring
Refer to Figure 2-2
1. Connect a dc power supply in series with the load to the (+PS) and
(-PS) power terminals. Note that the load (usually a monitoring
instrument) may be connected to either the (+) or (-) power lead.
2. Connect the thermocouple to the (+IN) and (-IN) input terminals.
Figure 2-2 Wiring Diagram for Thermocouple Transmitter