2. Control Functions
Control of Master/Slave group
SMGB0082 rev.1 - 07/2015
56
6 Forced operation order wiring. (External thermo operation)
When connecting forced operation wiring, it is possible to operate a specific chiller unit. (This is possible also during
system operation). However, this is only for chiller units which are stopped.
Also, in the case of air-cooled heat pump systems, the chiller units to which a forced operation order has been input
operate in the state of remote cooling/heating switching signal, so it is necessary to properly connect the cooling/
heating switching wiring as well.
Forced operation
switch
ON
OFF
Run
Stop
Operation mode is according to the
status of the cooling/heating switch
24
25
27
28
Forced operation
switch
Cooling/Heating
switch
Cooling
Heating
7 Functions concentrated in unit 1 (master unit)
By inputting the signal of the following wiring to unit 1, their settings become enabled for all the chiller units in the same
group.
• Fan forced operation order
• 2-temperature setting
• Night shift
•
Maximum current limitation
2.3.4 Other functions of the control of Master/Slave group
1 About Detachment
Modules stopped by an alarm stop or by a forced stop during operation, as well as modules that have lost communication
with Master module, become excluded from the target of the control of Master/Slave group. (The same applies for
Master module).
This state is called "Detachment". Also, modules with the local/remote switch in the PCB
a
(SW2) set to local side become
detached, too. It is not possible to output operation orders to modules under detachment. (It is possible to operate
modules in local setting with the Run button in the control panel of the modules as well as with forced operation order)
Also, system operation continues even if a detachment event occurs.
2 About recovery method to system from detachment state
Modules that have been once detached are not subject to the control of Master/Slave group unless performing recovery
operation. (However, modules that have become detached because of transmission abnormality are recovered
automatically as soon as transmission is restored ) Please perform recovery operation after removing the causes of the
Alarm and other factors. (Either one of 1 or 2 listed below).
N O T E
Recovery operation: please set the local/remote switch in thePCBa (SW2) to remote, and perform the following
operation:
• Press down the ON button in the control panel of the module which is under detachment.
• "System Recovery Signal": input from control (according to system conditions).
3 System Operation at Alarm occurrence
Exclude the modules affected by alarm stop, and continue system operation with the rest of the modules. (The same
applies in case that Master module is stopped by an alarm stop) However, processing of transmission abnormalities
differs according to the selected control of Master/Slave group.
Operation of chiller units that have lost communication with Master module.
4 Start-up Order
In case of starting up multiple Modules upon system startup, they are started up sequentially in 10-second intervals.
