SEM104TC Datasheet, PDF (6/8 Pages) List of Unclassifed Manufacturers – SEM104 SERIES

1.0 DESCRIPTION
The SEM104TC is a low cost thermocouple input two wire (4 to 20) mA temperature transmitter. The transmitter
is available in a number of standard sensor types and ranges, but if required the user may re-range the
transmitter to a preferred range within the limits shown below. Automatic thermocouple cold junction
compensation is provided. The output is directly referenced to the mV input, allowing linearisation to be
carried out by the loop monitoring instrumentation, if required. The device is housed inside a plastic
enclosure, suitable for head mounting into any DIN style enclosure. Screw terminals are provided for wire
connections. The enclosure provides access to the range setting links and trim potentiometers.
2.0 SPECIFICATION @ 20 ºC
Input
Isolated junction un-grounded thermocouple
Thermocouple Types
K
T
J
Minimum Span ºC
75
75
75
Maximum Span ºC
1000 400
760
Offset Range ºC
± 100 ± 100 ± 100
Accuracy (less CJ)
± 0.1 % FS
(0 to 100) ºC range
Overall Stability (inc. CJ) 0.04 %/ºC (0 to 100) ºC range
Input Impedance
> 1 MΩ
Lead Resistance
Typical 0.01 ºC/Ω, for Type K (0 to 100) ºC
Burn Out
Up scale standard, Down scale by link change.
Cold Junction
Automatic (0 to 70) ºC
Accuracy
0.2 ºC @ 20 ºC, tracking ± 0.05 ºC/ºC
Output Type
(4 to 20) mA (directly proportional to mV input)
Over-range < 25 mA ; Under-range < 3.5 mA
Supply Voltage
(10 to 30) VDC reverse connection protected.
Loop Sensitivity
10 µA /V
Temperature Stability Zero Drift typical 0.05 % /ºC
Span Typical 0.002 %/ºC
Loop Ripple
Less than 40 uA/V (measured at 1 V ripple 100 Hz)
Loop Resistance
(VSupply -10)/0.021
Response Time
2 ms to reach 70 % of final value
Ambient Temperature
(0 to 70) ºC operation, (-40 to 85) ºC storage
Ambient Humidity
(0 to 95) % non condensing
Connections
Recommended cable size 2.5 mm²
EMC Compliant with
EN50081-1
EN50082-1X
3.0 INSTALLATION
3.1 MECHANICAL
The transmitter is mounted using two 5.5 mm diameter holes, on standard 33 mm fixing centres. This
transmitter has been specifically designed to be mounted inside a DIN standard probe termination head
enclosure, which should provide adequate protection from moisture, corrosive atmosphere etc. All cable
entries should be sealed using the correct size cable gland. Care must be taken when locating the
transmitter to ensure the ambient temperature will remain inside the specified range of (0 to 70) ºC, for
best operation keep the ambient within the range (10 to 30) ºC.
The diagram below shows the mechanical layout.
Figure 1
ZS
Ø42.0 mm
23.0 mm
Mounting holes : 2 holes 5.5 mm diameter, 33 mm centres
The diagram below shows a typical application of the transmitter mounted inside a probe head enclosure,
with sensor wires entering through the centre hole.
Figure 2
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