Siemens Sinamics G120 Series Parameter Manual page 58

Parameters
List of Parameters
r0485 CO: Encoder counter value / Encoder count val.
CU240S Access level: 2
CU240S DP
Unit: -
CU240S DP-F
CU240S PN
Description: Shows the internal counter value of the encoder pulses.
p0491[0...2] Reaction on speed signal loss / Select enc. type
CU240S Access level: 2
CU240S DP
Quick comm. NO
CU240S DP-F
Can be changed: T
CU240S PN
Min
0
Description: Selects reaction on loss of speed signal.
Values: 0:
1:
p0492[0...2] Allowed speed difference / Allowed speed dif
CU240S Access level: 2
CU240S DP
Quick comm. NO
CU240S DP-F
Can be changed: T
CU240S PN
Min
0.00 [Hz]
Description: Parameter P0492 is used for low and high speed encoder loss detection (fault: F0090).
High speed encoder loss detection:
This condition occurs when the allowed frequency and the allowed difference of the speed signals between sam-
ples, set in P0492 is exceeded.
• f_act and f(t_2) - f(t_1) > P0492
Low speed encoder loss detection:
This condition occurs when the actual frequency is < P0492 when encoder loss occurs.
• Condition 1:
- r0061 = 0 and torque limit and then
- r0061 = 0 with setpoint frequency > 0 for time > P0494
• Condition 2:
- Act. freq. < P0492 and f(t_2) < P0492 and ASIC detect channel B loss
Dependency: This parameter is updated when motor start-up time P0345 is changed or when a speedloop optimisation is per-
formed (P1960 = 1).
There is a fixed delay of 40 ms before acting upon loss of encoder at high speeds.
Caution: P0492 = 0 (disabled):
When allowed speed difference is set to 0, both the high speed and low speed encoder loss detection are disabled,
thus encoder loss will not be detected.
If encoder loss detection is disabled and encoder loss occurs, then operation of the motor may become unstable.
Consideration also needs to be given to drive operation when the drive is operating in vector speed control or vector
torque control mode (P1300 = 21, 23) and the drive attempts to start the motor while it has a failed encoder.
Under these circumstances, the drive uses parameters P1520 and P1521 (the upper and lower torque limits
respectively) to decide when to trip.
In the case of a very low frequency set point, it may take the drive a considerable period to reach this condition, dur-
ing which time the drive can lose orientation.
1-58
Trip the drive
Warn and switch to SLVC if in VC
P-Group: Closed-loop control
P-Group: Encoder
Active: NO
Max
1
P-Group: Encoder
Active: YES
Max
100.00 [Hz]
© Siemens AG 2007 All Rights Reserved
SINAMICS G120 Control Units CU240S, Edition 05/2007
Data type: Unsigned32
Data set: -
Data type: Unsigned16
Data set: DDS
Factory setting
0
Data type: Floating Point
Data set: DDS
Factory setting
10.00 [Hz]