Omega Products TX1502A-E User Manual
Isolated 4 to 20 mA Transmitters
For Demanding Applications
Thermocouples, RTD (Pt100) or Ohms,
Millivolts, Milliamps, Volts
TX1500 Series
U Isolated to 1500 Vrms
U 2-Wire 4 to 20 mA
Operation
U 9 to 50V Compliance
U Turndown Ratio to 10:1
U NMV Protection to 120 Vac
U -40 to 85°C (-40 to 185°F)
Operation
U Shock Resistance
to 55 g
U NEMA 4X (IP66) Metal Case
U Field Scalable
Unmatched Electrical
Performance 2-Wire
Operation
Power is obtained directly from the
4 to 20 mA loop, with no need for
separate power input. This simplifies
field wiring and prevents noise
pickup from power lines.
TX1502A-K shown actual size.
Isolation to 1500 Vrms
(2100 Vp)
This exceptionally high CMV rating
from the input to the case or output
eliminates electrical ground loops
between the signal source and the
receiver. It also provides a high
degree of protection for the receiver
against electrical hazards, such
as accidental contact between the
signal source and an AC power line.
9 to 50V Compliance
The loop voltage driving the
transmitters can be from 9 to 50V
without loss of accuracy. The
exceptionally low 9V limit allows
the transmitters to be used with
low loop supply voltages, and it
maximizes the voltage drop allowed
in the current loop for intrinsic safety
Custom Scaling
Available! Specify Input
Signals Corresponding to
4 and 20 mA. Please Contact
Engineering for Details
barriers and load resistance. For
example, at the full 20 mA output
of the transmitter, a 750 Ω load can
be used with a 24 Vdc source and
a 150 Ω load can be used with a
12 Vdc source. In either case, there
will still be enough voltage left to
power the transmitter, namely 9 Vdc.
®
10:1 Turndown Ratio
Turndown ratio is defined as zero
suppression divided by span. The
exceptionally high 10:1 turndown
ratio possible with the TX1500
Series indicates that wide zero
offset can be combined with narrow
signal span for closed loop control
at high gain. The signal span can
also be wide for control of batch
operations, where a wide range of
signal levels may be encountered
over the entire batch cycle.
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Signal source:
T/C, RTD, mA
mV, V
T/C
Galvanic isolation
+
-
Electromagnetic interference (EMI)
4 to 20 mA current loop
-
Sensing
resistor
+
V = IR
Remote
ground
Isolated 2-wire
transmitter
Control room
ground
Classic Application of a TX1500 Series 2-Wire Isolated Transmitter
The transmitter amplifies a low-level voltage signal to a 4 to 20 mA current signal, which is immune to voltage noise pickup. .
The voltage detected in the control room is V = IR, where I is the loop current and R is the dropping resistor of the receiving
equipment. The isolation provided by the transmitter protects the receiving equipment and prevents ground
the remote signal ground and the ground of the control room.
High Overvoltage Protection
Overvoltage of 120 Vac may be
applied across the input or output
leads for 1 minute for all models
with voltage or thermocouple inputs.
Reverse polarity of 400 Vp may
be applied across the output leads
indefinitely. These exceptionally
high NMV overvoltage ratings
provide further protection against
possible electrical faults and
wiring errors.
Designed for Harsh
Environments
Extreme operating temperatures.
The operating temperature can
range from -40 to 85°C (-40 to
185°F) while meeting published
performance specifications. This
allows the TX1500 Series to be
used near furnaces or outdoors
in the winter. The exceptionally
wide operating temperature range
is made possible by a proprietary
electrical circuit and by extensive
use of computer-graded and
computer-matched electrical
components.
Resistance to shock and vibration.
The shock rating is 55 g (1.9 oz),
which includes a 1.8 m (6') drop
onto concrete. This is made possible
by a compact die-cast metal case,
which is only 74 mm (2.9") in
diameter, and by rugged mounting
of the electronics. The circuit board
assembly is in the shape of a rigid
box and is firmly soldered to the top
of the transmitter case.
Waterproof Case
The case is made of diecast zinc
alloy. It is waterproof to 35 kPa
(5 psi) and meets NEMA 4X (IP66)
standards. The top of the case
is sealed against the bottom with
a fluorosilicone gasket, and the
openings in the top of the case for
the zero and span adjustment, are
sealed with fluorosilicone plugs.
Explosion-Proof
Housing Options
Three external NEMA 7
explosion-proof and NEMA 4 (IP65)
waterproof, sand-cast, copper-free
aluminum enclosures with
corrosion-resistant “safety-blue”
polyester powder-coating for use in
hazardous locations. FM, UL, cUL
Certification: Class I, Groups B, C,
D; Class II, Groups E, F, G; and
Class III, Type 4X. Demko/ATEX
Certification: EX II 2 G D EEx d IIC.
Option EPH1-ATEX is a singleheight, all-metal housing for a single
TX1500 Series transmitter.
Option EPW2-ATEX is a doubleheight metal enclosure with a
glass window for a TX1500 Series
transmitter on the bottom and a
TX83A loop-powered indicator on top.
The TX83A augments the transmitter
with an LCD digital readout scaled in
engineering units and only adds a 2.5
V drop to the current loop.
Option EPW3-ATEX is a singleheight enclosure for one TX83A
loop-powered indicator. This
option includes 2 female 1⁄2 NPT
pipe fittings, all required internal
mounting hardware, and mounting
flanges for a wall or bulkhead.
Easy to Calibrate and Install
There is no need to specify different
models for different ranges of the
same signal type. Zero and span
are each set by push-on jumpers
for coarse range selection and by
a 15-turn precision potentiometer for
fine adjustment. The 2 potentiometers
are accessible outside the case
through openings that are normally
sealed by fluorosilicone plugs. To
assist in calibration, 2 test terminals
provide a 10 mV/mA output (200 mV
full scale). The scaling procedure is
explained in a comprehensive user’s
manual, which is shipped with every
unit.
loops between
N-47
TX1501 shown smaller
than actual size.
Quick Selection Guide by Input Type
Zero
Suppression Maximum Signal Signal Span for Input
Model No. Signal Type for 4 mA Output for 20 mA Output 4 to 20 mA Output Impedance
RTD -200 to 750°C 850°C 100 to 1050°C
TX1501 Pt100 -328 to 1382°1 562°F 180 to 1890°F N/A
Ω 0 to 365 Ω 400 Ω 35 to 400 Ω
TX1502A-J Type J T/C -50 to 660°C 760°C 100 to 810°C 5 MΩ
iron-constantan -58 to1220°F 1400°F 180 to 1458°F
TX1502A-K Type K T/C -50 to 1272°C 1372°C 100 to1422°C 5 MΩ
chromel-alumel -58 to 2322°F 2502°F 180 to 2560°F
TX1502A-T Type T T/C -50 to 350°C 400°C 50 to 450°C 5 MΩ
copper-constantan -58 to 662°F 752°F 90 to 810°F
TX1502A-E Type E T/C -50 to 900°C 1000°C 100 to 1050°C 5 MΩ
chromel-constantan -58 to1652°F 1832°F 180 to 1890°F
TX1504 Millivolts -30 to 60 mV 160 mV 5 to 100 mV 100 MΩ
TX1505 Milliamps -30 to 60 mA 160 mA 5 to 100 mA 1 Ω
TX1506-1 Low volts -3.5 to 6.0V 11V 0.5 to 5V 1 MΩ
TX1506-2 High volts -35 to 60V 110V 5 to 50V 1 MΩ
Common Specifications
Signal Output
Connection: 2-wire
Linear Range: 4 to 20 mA
Maximum Output: 35 mA
Voltage Compliance: 9 to 50 Vdc
Power Supply Rejection: 0.01% of span/V
Input/Output Protection:
CMV, Input to Case or Output: 2100 Vp per HV test,
354 Vp per IEC spacing
CMR, Input to Case or Output:120 dB, DC to 60 Hz
NMV Across Output Leads: 120 Vac for 1 min
Reverse Polarity Across Output Leads:
400 Vp
Accuracy: -40 to 85°C (-40 to 185°F)
Hysteresis and Repeatability: ±0.1% of span
6-month Stability Error: ±0.2% of zero
suppression
Error Due to 50°C Change in
Transmitter Temperature:
Zero Error: ±0.2% of zero suppression
Span Error: ±0.2% of span
Environmental
Operating Temperature: -40 to 85°C (-40 to 185°F)
Storage Temperature: -55 to 125°C (-67 to 257°F)
Relative Humidity: 0 to 100% (sealed case)
Watertight Proof Pressure: 35 kPa (5 psi)
Shock: 55 g, half sine, 9 to 13 ms duration
Vibration: 1.52 mm (0.06") double amplitude,
10 to 80 Hz cycled
Mechanical
Case Material: Zamak zinc alloy
Gasket Material: Fluorosilicone
Diameter: 74 mm (2.9")
Height, Including Barriers: 53 mm (2.1")
Weight: 380 g (13 oz)
Electrical Connection: #6 screws with wire clamps
Terminal Protection:
Standard: Screw terminal barriers plus barrier strip cover
CPB1 (Optional): Plastic cover for case top (protects T/C
screw terminals from air currents)
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