AERMEC MCR Manuel D'utilisation page 34

EMERGENCY OPERATION OF THE TTL NETWORK
Room probe absent Master
The operating principle of the master thermostat when operating without a room sensor (i.e. failure of its own local sensor) is as described above.
Room probe Absent Slave
Slave thermostat cards enter into emergency operation if not only their own local probe fails but also that of the master. In fact, if the slave probe fails while the master probe
is functioning correctly, the slaves continue to operate using the master probe.
If the master's probe fails, the slaves will start operating in emergency mode.
TTL GRID FROST PROTECTION
Master: as described in the "Frost protection" paragraph, the thermostat provides control over the room temperature as standard, to prevent it from dropping to freezing
values. If the master is operating in this state, it will force all slaves to operate in AUTO mode and setpoint 12°C even if they are operating in normal mode.
Slave: If, on the other hand, one of the slaves is in the logic of operating according to the frost protection (although the master is operating in normal mode), it will start to
operate in AUTO mode with a setpoint of 12°C. This is the only case in which the slave operates according to settings different from those dictated by the master.
10 COMMUNICATION PROTOCOL
The MCR control board is designed to connect with control and/or supervisory systems via two ModBus RTU communication buses; the thermostat board is always a commu-
nication slave.
Once communication with the supervisory system is established, the controller automatically enables the comfort function, i.e. the local interface control setpoint becomes a
simple deviation of ±3 or ±6 °C from the centralised setpoint.
Attention: The GLF grid thermostat can only communicate with the central system if it has a user interface.
For further information please refer to the following BMS manual (list of variables), which can be accessed via the following QR Code:
34 22/04 – 5572952_00