Basic Documentation

Functions
Handling system faults
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4.10 Handling system faults
If the room temperature exceeds or drops below the measuring range, i.e. above
49 °C or below 0 °C, the limiting temperatures blink, e.g., 0 °C or 49 °C .
In addition, the heating output is activated if the current setpoint is not set to Off,
the thermostat is in heating mode and the temperature is below 0 °C.
For all other cases, no output is activated.
The thermostat resumes Comfort mode as soon as the temperature is within the
measuring range.
For fault status messages on the Modbus, see Fault and alarms function on
Modbus [➙ 45].
4.11 Modbus RTU mode
The thermostat supports the communication protocol (Modbus RTU mode) as per
the Modbus specification (see http://www.modbus.org).
The device address range is 1...247.
The device address can be changed via parameter P81. (Factory setting = 1)
The available baud rates are 9600 bps, 19200bps, 38400 bps and 57600 bps.
The baud rate can be changed via parameter P82. (Factory setting = 19200 bps
The parity can be set to none (no parity), odd or even.
The parity can be changed via parameter P83. (Factory setting = even)
4.11.1 Fault and alarms function on Modbus
A fault is sent on the bus in the event of a fault (e.g., digital fault input, dewpoint,
communication configuration, etc.).
The alarm with the highest priority is displayed first and sent via bus if alarms occur
at the same time.
Temperature out of
range
Fault information
Device address
Baud rate
Parity
Fault information
Priority of alarms