Omega TX92A User manual

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TX92A
Miniature Temperature Transmitters
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User’s Guide
TM

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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i
TTAABBLLEEOOFFCCOONNTTEENNTTSSPPAAGGEE
1.0 GETTING STARTED
1.1 Unpacking. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Safety and EMC Considerations . . . . . . . . . . . . . . . . . . . . 1
1.3 General Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.4 Available Ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.5 Ordering Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.6 Shock Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.0 CONNECTING POWER AND SIGNAL INPUTS. . . . . . . . . 4
3.0 CALIBRATING THE TRANSMITTER. . . . . . . . . . . . . . . . . 5
4.0 SPECIFICATIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
LIST OF FIGURES AND TABLES
Figure 2-1 Power Input Setup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Figure 2-2 Pin Assignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Figure 3-1 Calibration Setup (Resistance Source). . . . . . . . . . . . . . . . 5
Figure 3-2 Calibration Setup (RTD Simulator). . . . . . . . . . . . . . . . . . . 6
Figure 4-1 Case Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Figure 4-2 Transmitter Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . 8
Table 1-1 Range/Models. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Table 2-1 Screw-Terminal Pin Assignment . . . . . . . . . . . . . . . . . . . . 4
Table 3-1 Fahrenheit Temperature to OHMs Conversion Chart . . . . . 6
Table 3-2 Celsius Temperature to OHMs Conversion Chart. . . . . . . . 6

ii

SECTION 1 GETTING STARTED
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 50 Vdc).
Always use a power supply, which complies with EN 60950 safety standard.
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 TX92A Series transmitter accepts platinum 100 ohm sensor type RTDs and will
produce a standard 4-20 mA output signal proportional to that produced by its
attached RTD input. The transmitter does NOT provide isolation between its input and
the 4-20 mA output; therefore, an ungrounded RTD is suggested to prevent possible
ground loops.
The transmitter provides amplification, common-mode rejection and controlling the
current draw from an 8-to-50 Vdc source to produce the 4-to-20 mA output signal.
As much as 800 ohms dropping resistance may be used in the power leads of the
TX92A when the unit is energized from a 24 Vdc source because of the small
compliance voltage needed by the unit.
1

1.4 Available Ranges
As specified in Table 1-1, the transmitter has 10 ranges. Depending upon the range,
the transmitter can measure temperature span as narrow as 180°F or as wide as
1000°F. A multi-turn, top-accessible potentiometer provides fine span tuning. A
second top-accessible, multi-turn potentiometer provides a zero adjustment which
allows placement of the 4-mA output temperature within +/- 25% for Fahrenheit and
+/- 10% for Celsius of nominal span (refer to Section 3.0, Calibrating the Transmitter,
for more details). Models TX92A-*-L are transmitters with the 4-20mA output
linearized to temperature.
Table 1-1. Range/Models
RRaannggeeMMooddeell
-40 to 140°F TX92A-1 TX92A-1-L
0 to 200°F TX92A-2 TX92A-2-L
0 to 300°F TX92A-3 TX92A-3-L
0 to 500°F TX92A-4 TX92A-4-L
0 to 750°F TX92A-5 TX92A-5-L
0 to 1000°F TX92A-6 TX92A-6-L
-0 to 100°C TX92A-7 TX92A-7-L
-0 to 150°C TX92A-8 TX92A-8-L
-0 to 250°C TX92A-9 TX92A-9-L
-0 to 400°C TX92A-10 TX92A-10-L
2

1.5 Ordering Guide
The model number describes the functionality of the transmitter.
Model Temperature Range
1 -40 to 140°F
2 -0 to 200°F
3 -0 to 300°F
4 -0 to 500°F
5 -0 to 750°F
6 -0 to 1000°F
7 -0 to 100°C
8 -0 to 150°C
9 -0 to 250°C
10 -0 to 400°C
-L 4-20mA output linearized to temperature
FS **Factory Scaling Option:
**Factory Scaling available for additional charge. Consult factory.
To order additional transmitters, specify TX92A followed by the model number. For
example:
TX92A-2 = RTD Transmitter with a temperature range of -0 to 200°F.
or
TX92A-2-L = RTD Transmitter with the 4-20mA output linearized to temperature and
a temperature range of -0 to 200°F.
1.6 Shock Resistance
Lightweight TX92A transmitter circuit boards are fabricated from rigid, shock resistant
materials with the components soldered to the circuit board.
The TX92A transmitter's small size permits mounting into thermowells or wall mount-
ing in confined areas.
3
TX92A-

4
2.0 CONNECTING POWER AND SIGNAL INPUTS
1. Verify that the transmitter is connected for the correct power
voltage rating.
2. Connect the power supply to pin 4 and the resistance load to pin 5.
3. Connect the sensor to pins 1, 2 and 3.
The transmitter has no power on switch, so it will be in operation as soon as
you apply power.
Figure 2-1 Power Input Setup
+PS and -PS screws accept 2mm (13 gauge) or lighter wire. Input range is 8-50 Vdc.
Table 2-1. Screw-Terminal Pin Assignment
Figure 2-2 Pin Assignment
1 RTD
2 RTD
3 M (Sense)
4 +Power/Signal Output
5 -Power/Signal Output
12345
1
ZS
RANGE:
TYPE: JKTEP
2 3 4 5 6 7 8 91011
IN IN PS
M
PS
DC SUPPLY
8-- 50 VDC
4-- 20mA
INT
INT
M
+PS
PS
R LOAD
RTD
TRANSMITT R
1
2
3
5
4

5
3.0 CALIBRATING THE TRANSMITTER
Calibration Setup:
1. Insert the reference RTD.
2. Connect RTD simulator.
3. Connect DMM monitor and power supply.
Figure 3-1. Calibration Setup (Resistance Source)
To calibrate the transmitter, follow these steps (refer to Figure 3-1):
1. Locate the model number in Table 3-1 or 3-2 and set the resistance source to
the LO-IN value.
2. Adjust the Zero potentiometer until the milliammeter reads 4.00 mA.
3. Set the resistance source to the HI-IN value (in your appropriate table) and read
the output current on the milliammeter.
4. Adjust the Span potentiometer to obtain the 20 mA on the milliammeter.
5. Set the resistance source to LO-IN resistance. If the output current is not 4.00
mA, repeat steps 2 through 7.
6. When calibration is complete, remove the transmitter from the setup.
1
2
3
4
5
ZS
RESISTANCE
SOURCE
DC SUPPLY
24 VDC
DMM
(4–20 mA)
MONITOR
(–)
(+)
(–)
(–)
(+)
(+)
COPPER
WIRE
250 Ohms
INPUT
RTD
WIRE
SPAN
ZERO

6
3.0 CALIBRATING THE TRANSMITTER (Continued)
An RTD calibrator may be used in place of the resistance source - refer to Figure 3-2.
Figure 3-2. Calibration Setup (RTD Simulator)
Table 3-1. Fahrenheit Temperature to OHMS Conversion Chart
Table 3-2. Celsius Temperature to OHMS Conversion Chart
1
2
3
4
5
ZS
DMM
(4–20 mA)
MONITOR
(–)
(+)
(–)
(+)
250 Ohms
INPUT
WIRE
SPAN
ZERO
RTD
CALIBRATOR
DC SUPPLY
24 VDC
VVaalluueeMMooddeellNNuummbbeerr//RRaannggee
TTXX9922AA--7788991100
(0 to 100°C) (0 to 150°C) (0 to 250°C) (0 to 400°C)
LO IN 100 Ω 100 Ω 100 Ω 100 Ω
HI IN 138.51 Ω 157.33 Ω 194.10 Ω 247.09 Ω
VVaalluueeMMooddeellNNuummbbeerr//RRaannggee
TTXX9922AA--112233445566
(-40 to 140°F) (0 to 200°F) (0 to 300°F) (0 to 500°F) (0 to 750°F) (0 to 1000°F)
LO IN 84.27 Ω 92.95 Ω 92.95 Ω 92.95 Ω 92.95 Ω 92.95 Ω
HI IN123.24 Ω135.85 Ω156.96 Ω197.71 Ω246.74 Ω293.56 Ω