JUMO 14597 safetyM STB/STW Ex - Safety Temperature Limiter and Safety Temperature Monitor Operating Manual - Manual (Page 124)

10 Setup program
2013-04-01
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10.3 Forgotten the code?
If you forget the code, it can be read out via the USB interface and the setup program.
h
Use Data transfer

from device.
The read-out code now appears in the setup program.
It can now be retained or changed.
If "0" is set and transferred to the device, the code request is deactivated and the configuration level is freely accessible.
10.4 Special function: thermocouple reverse voltage protection
If the voltage of a thermocouple is reversed, measured values
are shown that do not correspond to reality, for example as
negative values are shown instead of the anticipated positive
temperatures.
This may mean that the set limit value is never achieved. For
this purpose, an additional limit value is defined and is set at -
200 °C ex works. The alarm relay is triggered when this limit
value is not met.
This value must be chosen carefully so that potential reverse
voltage can be determined.