Siemens SINAMICS V20 Series Operating Instructions Manual page 209

Parameter Function
The diagram below shows a typical pumping system.
A similar system could be set up using fans and air ducts, instead of pumps and pipes.
By default the motor states are controlled from digital outputs (DO).
In the text below, the following terminology will be used:
MV - Variable speed (Inverter controlled motor)
M1 - Motor switched with digital output 1 (DO1)
M2 - Motor switched with digital output 2 (DO2)
Staging: The process of starting one of the fixed speed motors.
De-staging: The process of stopping one of the fixed speed motors.
When the inverter is running at maximum frequency, and the PID feedback indicates that a higher speed is
required, the inverter switches on (stages) one of the digital output controlled motors M1 and M2.
At the same time, to keep the controlled variable as constant as possible, the inverter must ramp down to
minimum frequency.
Therefore, during the staging process, PID control must be suspended (see P2378 and diagram below).
Staging of external motors (M1, M2)
P 2371 = 0
When the inverter is running at minimum frequency, and the PID feedback indicates that a lower speed is
required, the inverter switches off (de-stages) one of the digital output controlled motors M1 and M2.
In this case, the inverter must ramp from minimum frequency to maximum frequency outside of PID control
(see P2378 and diagram below).
Destaging of external motors (M1, M2)
P2371 = 0
SINAMICS V20 Inverter
Operating Instructions, 07/2012, A5E03728167
Range
1. 2.
- - -
1 - M1 M1
2 - M1 M1+M2
3 - M1 M2
1.
- -
1 M1 -
2 M1+M2 M1
3 M1+M2 M2
Factory Can be
default changed
3. 4.
- -
M1 M1
M1+M2 M1+M2 M1+M2
M1+M2 M1+M2 M1+M2
2. 3. 4.
- - -
- - -
- - -
M1 - -
Scaling Data
set
5. 6. 7.
- - -
M1 M1 M1
M1+M2 M1+M2
M1+M2 M1+M2
5. 6. 7.
- - -
- - -
- - -
- - -
Parameter list
7.2 Parameter list
Data Acc.
type Level
t
t
209