V2.2
-00
20
REGULATION OF UNITS IN PARALLEL
With CONSEG = 6°C
ENCLG
= 1,5°C
DIFETG
= 1,5°C
Notes :
THERG can only be incremented by a stage if it has not increased for a time defined using
instructions TPTHERM.
THERG can only be decremented by a stage if it has not decreased for a time defined using
instructions TPTHERD.
F
Control of isolation valves for evaporators on each unit
If the regulation thermostat THERG requests operation of unit Gn, valve V2Vn is sent a command to open.
F
Operation of units
The start-up of the next priority unit Gn is authorised if the opening command has been issued to valve V2Vn for
at least TPV2V (variable time). The hard contact representing this authorisation to switch a unit on (associated
variable MAARGn) must be wired to the "remote on / off" input connection for the machine.
Each unit controls its own compressors and pump in accordance with its own set point (see “cold thermostat”
chapter page 5). For better general regulation, it is recommended to set unit instructions to the same value as
CONSEG.
F
Fault management and automatic unit logging
Each unit sends its availability state to the general regulation card. Depending on the overall availability of all
units, an optimal priority order PRIG is defined (units with no faults are put at the top of the priority list) :
In order to level out operating times for the different units, and if they are all available, PRIG changes
automatically once a week, on Monday at 6 pm.
If the temperature sensor in the chamber is defective, all the valves are opened and, when the time interval
TPV2V is up, start-up authorisation is issued to all the units.
PRIG
Ordure of unit start-up
0
G1 / G2 / G3 / G4
1
G4 / G1 / G2 / G3
2
G3 / G4 / G1 / G2
3
G2 / G3 / G4 / G1
Units start-up
Unit stop
THERG
TBAL (°C)
THERG
TBAL (°C)
0
ð
1
7,5
1
ð
0
6
1
ð
2
9
2
ð
1
7,5
2
ð
3
10,5
3
ð
2
9
3
ð
4
12
4
ð
3
10,5