External Current Measurement Via X21A Or X_I_Ist - Siemens SINAMICS DCM Operating Instructions Manual

Connecting
6.6 Measurement of the armature current
S700 switch positions:
Remove R701.
Parameter settings
p51822 =
p51823 =
p51824 =
Load
The load resistor should be located externally and grounded with the LEM transformer's
power supply. The value should be dimensioned to produce a 1 V voltage at the rated
current.
6.6.4

External current measurement via X21A or X_I_IST

X21A-23 and X_I_IST-1 = I_IST, negative actual current value
X21A-24 and X_I_IST-2 = M_I_IST, reference potential
S700 switch positions
The difference amplifier is active. The input signal is inverted and reduced to a tenth of its
value (-10 V to 1 V at rated DC current or -30 V to 3 V at the control limit).
Parameter settings
p51822 =
p51823 =
p51824 =
98
2 – 3 connected
5 – 6 connected
8 – 9 connected
Rated armature DC current
Input voltage at rated armature current
5 (bipolar)
1 – 3 connected
5 – 6 connected
8 – 9 connected
Rated armature DC current
Input voltage at rated armature current/10
4 for unipolar (negative) actual current value signal
5 for bipolar actual current value signal
SINAMICS DCM Control Module
Operating Instructions, 06.2010, C98130-A7067-A1-02-7619