Senquip ORB-X1-G, User Manual

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6.4 Thermocouple Interface
The ORB-X1 has a thermocouple interface.
Pins 11 and 12 on the ORB header are specifically for connection to a thermocouple to allow temperature
measurement. The positive terminal of a thermocouple, typically yellow for K-type, should be connected
to pin 12 and the negative terminal, typically red, to pin 11. The thermocouple input is extremely sensi-
tive and no other connections should be made except directly to thermocouples.
Warning Connection of anything to pins 11 or 12 except a thermocouple can result in permanent
damage to the thermocouple input and potentially to the ORB as well.
Thermocouples come in various types. The ORB supports K, J, T, N, S, E, B and R-Type thermocouples.
Typical temperature measurement accuracy is +-0.5°C with a resolution of 0.0625°C. Temperature
measurement accuracy is guaranteed to be +-1.5°C accurate, based on an ambient temperature of between
0 to +85°C. Note that the temperature of the body being measured can be hotter it colder than 0 to +85°C;
the 0 to +85°C range applies only to the ambient (air) temperature..
A thermocouple is comprised of at least two metals joined together to form two junctions. One is
connected to the body whose temperature is to be measured; this is the hot or measuring junction. The
other junction is connected to a body of known temperature (the terminal block in the ORB); this is the
cold or reference junction. Therefore the thermocouple measures unknown temperature of the body with
reference to the known temperature of the other body.
Figure 6.11. Typical thermocouple polarity
Note The negative terminal of a thermocouple is typically red. A thermocouple connected incorrectly
may appear to work at some temparatures.
In the ORB, the ambient temperature accuracy (Cold junction accuracy) is typically +-0.5°C or a
maximum of +-1.0°C over the ambient temperature range of 0 to +85°C.
The ORB is capable of measuring the hot junction to an accuracy of typ-0.25°C or a maximum of
+-0.5°C over the ambient temperature range 0 to +85°C and assuming the below thermocouple tempera-
ture ranges:
6.4.1 Specification
Parameter Specification
Temperature accuracy +-0.5°C (typical)
Temperature accuracy +-1.5°C (0 to 85°C)
Resolution +-0.0625°C
ORB User Guide, Release 1.1
68 Chapter 6. External Sensors