ETAS
Thermo Channels ("TH1-4" Connections)
ES930.1
-
User Guide
30
4.1.4
Open TC Detection
The Open TC Detection assembly monitors the connections of the thermo
channels. If an open connection is diagnosed, e.g. in case of missing thermo
-
couples, this information can be displayed for every thermo channel in the
application software.
4.2
Measurement Error
For the measurement with thermocouples, the entire maximum measurement
error is comprised of different partial errors. The partial errors are:
• Base accuracy
T
g
• Maximum temperature drift
T
d
• Measurement error that depends on the internal resistance of the ther
-
mocouple
T
i
The maximum total error to be expected is the sum of all partial errors.
T =
T
g
+
T
d
+
T
i
The size of the partial errors depends on the type of thermocouple.
4.3
Electrical Isolation
The thermo channels are electrically isolated from each other. Each thermo
channel is electrically isolated from the supply voltage and from the housing of
the module.
Hence, the use of non-isolated thermocouples in non-floating installations is
also possible without a restriction on accuracy.
