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15.
Thermocouple isolation and interference
issues
To ensure accurate and reliable performance the following points should be
understood and taken into consideration:
Galvanic isolation is essential
When using multiple non insulated thermocouple probes it is essential that full
galvanic isolation exists between the probes. Failure to do so will create
reading errors.
Current loops
When using thermocouple probes connected to a common transmitter which
is powered from a source other than internal batteries, potential current loops
can exist causing reading errors. If it is essential that the transmitter is
powered externally, the AC power supply must be a type which has extremely
low AC leakage current (such as medical grade types).
It is preferred that only the Eltek MP12U power supply is used. In case of
doubt, contact Eltek.
Induced voltage interference
When using thermocouples with long leads in the presence of electrical
interference (e.g. welding equipment or heating control systems, especially
oven furnace control systems) voltages can be induced into the thermocouple
tip which will lead to reading errors.
Ensure that thermocouples are not located close to electrical
interference.
RxConfig will poll the receiver for meter readings at regular intervals (the meter
refresh time) when the meter window is displayed and the PC is connected to
the receiver.
