Local Fan Coil Network; Operating Principle - AERMEC VMF-E19 Manual Del Usuario

LOCAL FAN COIL NETWORK

NETWORK STRUCTURE
The VMF-E19 thermostat is designed to interact with other thermostats of the VMF range via serial communication based on the
TTL logic standards with low throughput. This communication is essential for the exchange of information within small fan coil
networks. The network consists of up to 6 thermostats and has a maximum length of about 30 metres. These limits are designed
to meet the needs of small areas containing several fan coils that need to be managed from a single command point. More
specifically, the network always has a master (that the VMF-E2/E4 user interface is connected to) that commands the operation
of the slaves linked to it, on the basis of the settings made on the user interface.
VMF-E4
E4
As shown in the over figure. It's not possible to have a VMF-E2/E4 local interface for every slave thermostat.

OPERATING PRINCIPLE

The master fan coil (i.e. the one housing the user interface) makes cyclical transmissions to the slave units to set the following
information on them:
o adjustment setpoint
o operating mode (OFF, AUTO, V1, V2, V3, AUX)
o operating season
This means the slave fan coils cannot work with settings other than those dictated by the master (except in certain cases).
Ambient probe: the ambient adjustment probe isn't necessary on the slave fan coils because they can use the adjustment probe
of the master. If you want to avoid micro climates however, you can install it on the slaves as well; in this way, their adjustment
will be made with the relative probe. In the specific event that the ambient probe on the master is faulty, slaves without a probe
will work in emergency mode (like the master), whereas slaves with an ambient probe will carry on working normally.
Water probe: you can decide whether or not to install a water probe on the various fan coils of the TTL network. Fan coils with a
probe will use it for the minimum and maximum checks envisaged, whereas ventilation is always enabled for fan coils without a
probe.
Microswitch input: this is the only digital input enabled on all the slaves of the network. If the contact is opened (i.e. fin closed),
the thermostat is turned OFF regardless of whether it's master/slave (even if it's the master of the network, only the thermostat
switches off, not the entire network).
External contact input: this digital input is inhibited on all the slave fan coils (enabled on the master only). If the master input is
closed, all the slave fan coils of the area are deactivated.
Presence sensor input: this digital input is only active on the master fan coil that uses it to determine (as explained in the "Sleep
function" paragraph) the adjustment setpoint that is sent to the slaves.
Anti-freeze function: this mode is the only case in which a slave in this condition can work with settings not envisaged by the
master. In fact, when the fan coils - regardless of whether they're master or slave - enter anti-freeze mode, they start working as
explained in the "Anti-freeze protection" paragraph above.
FAULTS ON THE TTL NETWORK
No Master-Slave communication: the slave fan coils cyclically wait to receive the area settings from the master fan coil. If a slave
is no longer communicating with the master for any reason, it goes to OFF (disabling of all loads) 10" after the last command
correctly received.
No Master-User interface communication: if the master is no longer communicating with the user interface, it goes to OFF 10"
after the last command received from the interface. The master will send the OFF command to all the slaves too. On the user
interface, the pink LED and thermostat LED will flash to indicate the lack of communication.
VMF-E19 MASTER VMF-E19 SLAVE
Max 30 metres long
Lunghezza Max 30 metri
AVMFE19LJ 2011 - 5779300_05
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