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Start and stop functionality
Two overall types of start/stop functions are provided
by the cascade controller option, one type quickly
stops all pumps while the other stages off the pumps in
a sequence, allowing for a controlled pressure stop.
Do not use these functions as emergency
stops. Some functions do not turn
off all pumps!
Type
System stop and start via
LCP
Start of lead pump via LCP
System start and stop
Stop and start of lead-pump
only
Fast system stop
When only the lead pump is stopped, the cascade
controller will try to maintain the pressure in the system,
by staging and destaging the remaining pumps.
NB!:
Should the drive trip for any reason, the
cascade controller can continue operation
with the remaining pumps. Only at live zero
where Parameter 318 Live zero functionality is set
to (STOP) or (STOP AND TRIP) or at Warning 8 (DC
UNDERVOLTAGE), all pumps will stop.
It is also possible to stop every single pump in the
system manually e.g. for service. Please read below.
NB!:
Please note that par. 719 and 720 are
indexed parameters.
MG.70.A1.02 - VLT is a registered Danfoss trademark
Terminal and parameter
STOP/OFF key AUTO/START key
HAND/START key
Terminal 17 - parameter 301 - (SYSTEM
START)
Terminal 18 - parameter 302 - (START)
Terminal 27 - parameter 304 - (COAST
INVERSE)
VLT® 7000 Booster
The Start and Stop functions are described in the
table below and are valid for all modes available. In
a sequenced stop, there is a one ramp-down time
delay between each destaging of the pumps.
Description
The lead pump decelerates to a
stop and all constant speed pumps
are stopped at a time.
Only the lead pump is running. If
more pumps are running, they are
destaged with a controlled stop.
At digital input low, the lead pump
decelerates to a stop, and then
provides sequenced stop for all
constant speed pumps.
At digital input low, the lead pump
decelerates to a stop. The constant
speed pumps continue to operate
normally controlled by the cascade
controller in the VLT.
At digital input low, the constant
speed pumps stop immediately.
The lead pump coasts to a stop.
Quick Menu 34 Par. 719 Pump enable
Par. 719 Pump enable
(PUMP ENABLE)
Value:
0
1
Function:
If a pump is to be removed from the system due to
repairs or service this can be done by disabling the
specific pump. The system will continue without any
interruption, and the pressure will be controlled as good
as possible by the remaining pumps. Disabling a pump
will lead to an immediate destaging of the pump, and
it will not be staged on until it is enabled again.
Please note, that the lead pump cannot be
disabled. It is not possible to disable pumps in
pump combination 1-4 (par. 701).
1: Enable
0: Disable
1
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