Siemens SINUMERIK 840D sl Series Diagnostics Manual page 772

Overview of Alarms
Cause: The amplitude (A^2 + B^2) of track A or B is not within the tolerance bandwidth.
SMC20:
The nominal signal level is at 500 mV (500 mV -25 % / +20 %). The response threshold is
< 300 mV.
SMC10:
The nominal signal level is at 2900 mV (2.0 Vrms). The response threshold is < 1414 mV
(1.0 Vrms).
Alarm value (r2124, decimal):
Low word:
Amplitude square root(A*A + B*B).
SMC20:
A signal level of 500 mV peak value corresponds to the numerical value 299A hex = 10650
dec.
SMC10:
A signal level of 2900 mV peak value corresponds to the numerical value 3333 hex =
13107 dec.
High word:
Angle 0 to 65535 corresponds to 0 to 360 degrees of the fine position. Zero degrees is at
the negative zero crossover of track B.
Remedy: - check the speed range, frequency characteristic (amplitude characteristic) of the
measuring equipment is not sufficient for the speed range.
- check that the encoder cables are routed in compliance with EMC.
- check the plug connections.
- replace the encoder or encoder cable.
- check the encoder module (e.g. contacts).
- dirty code disk
- aged lighting system.
233418 <location>Encoder 3: Speed difference per sampling rated exceeded
Reaction: NONE
Acknowledge: NONE
Cause: The speed difference between two sampling cycles has exceeded half the value of
parameter p0492.
The error is only evaluated for HTL/TTL encoders.
Alarm value (r2124, decimal):
Speed difference per current controller clock cycle in increments.
Remedy: - check the tachometer feeder cable for interruptions.
- check the grounding of the tachometer shielding.
- if required, increase the setting of p0492.
233419 <location>Encoder 3: Track A or B outside the tolerance range
Reaction: NONE
Acknowledge: NONE
Cause: The amplitude, phase or offset correction for track A or B is at the limit.
Amplitude error correction: Amplitude B / Amplitude A = 0.78 ... 1.27
Phase: <84 degrees or >96 degrees
SMC20: Offset correction: +/-140 mV
SMC10: Offset correction: +/-650 mV
Alarm value (r2124, hexadecimal):
xxx1: Minimum of the offset correction, track B
xxx2: Maximum of the offset correction, track B
xx1x: Minimum of the offset correction, track A
xx2x: Maximum of the offset correction, track A
x1xx: Minimum of the amplitude correction, track B/A
x2xx: Maximum of the amplitude correction, track B/A
1xxx: Minimum of the phase error correction
2xxx: Maximum of the phase error correction
2-772
SINUMERIK 840D sl/840D/840Di/810D Diagnostics Guide (DA), 08/2005 Edition
© Siemens AG, 2005. All rights reserved
08/2005