VEM VEMoDRIVE VSI 2.0 HD, Instruction Manual

Page: 130 / 244

128 Functional Description CG Drives & Automation, 01-5326-01r3b
Example 2 PID control = inverted (tank level
control)
[321] = F (AnIn)
[322] = m
[310] = 7 m
[342] = 2 s (inactive since [386] is activated and have higher
priority)
[381]= Inverted
[386] = 30 s
[387] = 1 m
The AC drive will stop/sleep when the speed (PID output) is
below or equal to Min Speed for 30 seconds. The AC drive
will activate/wake up when the “Process value” goes above
the PID Activation Margin which is related to the process
reference, i.e. goes above (7+1) m. See Fig. 97.
Fig. 97 PID Stop/sleep with inverted PID
PID Steady State Test [388]
In application situations where the feedback can become
independent of the motor speed, this PID Steady Test
function can be used to overrule the PID operation and
force the AC drive to go in sleep mode i.e. the AC drive
automatically reduces the output speed while at the same
time ensures the process value.
Example: pressure controlled pump systems with low/no
flow operation and where the process pressure has become
independent of the pump speed, e.g. due to slowly closed
valves. By going into Sleep mode, heating of the pump and
motor will be avoided and no energy is spilled.
PID Steady state test delay.
Communication information
PID Steady State Margin [389]
PID steady state margin defines a margin band around the
reference that defines “steady state operation”. During the
steady state test the PID operation is overruled and the AC
drive is decreasing the speed as long as the PID error is
within the steady state margin. If the PID error goes outside
the steady state margin the test failed and normal PID
operation continues, see example.
Communication information
NOTE: It is important that the system has reached a
stable situation before the Steady State Test is initiated.
Default: Off
Range: Off, 0.01–3600 s
[711] Process Value
[387]
[712] Speed
[341] Min Speed
[386]
Stop/Sleep
[310] Process Ref
Activate/Wake up
388 PID Stdy Tst
Stp Off
Modbus Instance no/DeviceNet no: 43373
Profibus slot/index 170/22
EtherCAT index (hex) 4d2d
Profinet IO index 19757
Fieldbus format Long, 1=0.01 s
Modbus format EInt
Default: 0
Range: 0–10000 in process unit
Modbus Instance no/DeviceNet no: 43374
Profibus slot/index 170/23
EtherCAT index (hex) 4d2e
Profinet IO index 19758
Fieldbus format
Long, 1= 1 rpm, 1
%, 1°C or
0.001 if Process
Value/Process Ref
using a [322] unit
Modbus format EInt
389 PID Stdy Mar
Stp 0
9(0R'ULYH 96, 9(0 U