FCU 500, FCU 505 · Edition 02.17
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Parameters
12 .3 .2 Thermocouple
Parameter 22
The type of double thermocouple can be selected using
parameter 22.
The following Class 1 double thermocouples may be
used. The thermocouple should be selected on the
basis of the switching point for high temperature opera-
tion and the maximum furnace temperature that can
be reached.
Parameter 22 = 1: Type K double thermocouple NiCr-Ni
(0 to 1200°C)
Parameter 22 = 2: Type N double thermocouple
NiCrSi-NiSi
(0 to 1200°C)
Parameter 22 = 3: Type S double thermocouple
Pt10Rh-Pt
(0 to 1600°C)
Thermocouples connected to the integrated tempera-
ture module for the safety temperature limiter (STL)
and safety temperature monitor (STM) are monitored
for cable discontinuity or short-circuit. This is only pos-
sible with double thermocouples.
It is not permitted to use single thermocouples and
connect the inputs in parallel using wire straps. If sepa-
rate sensor fittings are used, they must be installed
next to each other so that they both record the same
temperature.
12 .3 .3 Temperature difference limit value
Parameter 23
The maximum temperature difference (0 to 100K) be-
tween the two double thermocouples is defined using
this parameter.
If the temperature difference is exceeded, the FCU will
perform a fault lock-out.
