VEM VEMoDRIVE VSI 2.0 HD, Instruction Manual

Page: 136 / 244

134 Functional Description CG Drives & Automation, 01-5326-01r3b
Settle Time Start [39D]
The settle start allows the process to settle after a pump is
switched on before the pump control continues. If an
additional pump is started D.O.L. (Direct On Line) or Y/
,
the flow or pressure can still fluctuate due to the 'rough'
start/stop method. This could cause unnecessary starting
and stopping of additional pumps.
During the Settle start:
• PID controller is off.
• The speed is kept at a fixed level after adding a pump.
Communication information
Transition Speed Start [39E]
The transition speed start is used to minimize a flow/
pressure overshoot when adding another pump. When an
additional pump needs to be switched on, the master pump
will slow down to the set transition speed start value, before
the additional pump is started. The setting depends on the
dynamics of both the master drive and the additional drives.
The transition speed is best set by trial and error.
In general:
• If the additional pump has 'slow' start/stop dynamics,
then a higher transition speed should be used.
• If the additional pump has 'fast' start/stop dynamics,
then a lower transition speed should be used.
Communication information
Example
Max Speed = 1500 rpm
Min Speed = 200 rpm
TransS Start = 60%
When an additional pump is needed, the speed will be
controlled down to min speed + (60% x (1500 rpm - 200
rpm)) = 200 rpm + 780 rpm = 980 rpm. When this speed is
reached, the additional pump with the lowest run time
hours will be switched on.
Fig. 103 Transition speed start
Fig. 104 Effect of transition speed
Default: 0 s
Range: 0-999 s
Modbus Instance no/DeviceNet no: 43173
Profibus slot/index 169/77
EtherCAT index (hex) 4c65
Profinet IO index 19557
Fieldbus format Long, 1=1 s
Modbus format EInt
Default: 60%
Range: 0-100% of total min speed to max speed
Δ
39D Settle Start
Stp 0s
39E TransS Start
Stp 60%
Modbus Instance no/DeviceNet no: 43174
Profibus slot/index 169/78
EtherCAT index (hex) 4c66
Profinet IO index 19558
Fieldbus format Long, 1=1%
Modbus format EInt
NOTE: If set to 100 %, the transition speed, when
starting pumps, is ignored and no speed adaption is
made.
I.e. the slave pump is started directly and speed of the
master pump is maintained.
(NG_50-PC-16_1)
Speed
Actual
Trans
Min
Switch on
procedure starts
Additional pump
Master pump
Flow/Pressure
Actual start
command of next
pump (RELAY)
Flow/Pressure
Transition speed
decreases overshoot
Time
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