EWWD440~850AAYNNO**
Packaged water-cooled water chillers
4PW25558-1B
Installation and operation manual
29
I/O timing of various contacts
1.
Start of the unit
2.
Low load stop
3.
Stop caused by an individual compressor error
When "2UNITS" is selected in "UNITS TO CONTROL" on the
"SETTING" screen of the graphic panel display, the other
compressor continues operation.
There is no function to start the other compressor automatically
in case "1UNIT" is selected in "UNITS TO CONTROL" on the
"SETTING" screen of the graphic panel display when the
selected compressor falls into abnormal stop.
1
The signal to switch the operation mode must be input at least 1
second before operation command (ON
➞
OFF, OFF
➞
ON)
2
ON: Thermal storage mode
OFF: Cooling mode
3
The unit accepts the operation command
4
Signal is transmitted immediately after the unit accepts the
operation command. (However, time lag of maximum 1 second
may occur).
5
Signal is transmitted immediately after low load stop or when
ON-OFF limiting ends. (Identical to 88WEX if low load stop or
ON-OFF limitation do not prevail).
6
Return of all pump interlock signals so that the interlock circuit
closes within 180 seconds.
7
If the interlock signal does not return within 180 seconds, a unit
error is confirmed (5X-3 output) and the operation command is
destroyed. If contacts disconnect for 5 seconds in a row during
normal operation to, the same unit error is confirmed.
OFF
OFF
OFF
OFF
OFF
OFF
ON
ON
ON
ON
ON
ON
1
3
2
4
5
6+7
Only for operation
mode command
(thermal storage
or cooling)
(monitor 88MD -
optional)
Operation
command
(local/remote)
Chilled water
pump operation
command
(88WEX)
Cooling water
pump operation
command
(88WCX)
Pump interlock
(AXP1, AXP2)
Operate/stop
monitor (2-88X)
Start of
compressor to
start first
NOTE
■
When Run/Stop of the unit is performed remotely
under instantaneous contact specification, set the
pulse signal width to the unit as 200 msec or
more.
The unit may not recognize the narrow signal
width.
■
Any actions on the graphic panel display or signal
input to the unit within 30 seconds immediately
after power-up to the unit may not be accepted.
During 30 seconds immediately after powering up
the control circuit, communication connection
check between PLC and graphic panel display is
made.
1
Low load stop
2
Stop
3
Restarts after timer count-up in case ON-OFF limitation timer is
activated.
4
Normally ON
5
When the pump interlock contact disconnects for 5 seconds
continuously during low load stop, a unit error is confirmed (5X-3
output) and the unit falls into abnormal stop condition.
1
2
4+5
4+5
4
3
Low load thermo
Compressor
operation
Chilled water pump
operation command
(88WEX)
Cooling water
pump operation
command (88WCX)
Operate/Stop
monitor (2-88X)