Operating instructions

Commissioning
5.8 Commissioning the Encoder
Control Units CU240S
Operating Instructions, 10/2007, A5E00766042B AC
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5.8.2 Encoder Fault Codes
Description
The Encoder Interface has only one fault code, – F0090. This condition occurs when the
allowed frequency rate of change, set in P0492[3] is exceeded or when low speed encoder
loss is detected.
Note
The reason for the encoder loss will be given in the level 3 parameter r0949:
r0949 = 1 means encoder loss of channel A or channel B, or encoder loss due to high speed
(shaft speed > P0492).
r0949 = 2 means encoder loss of channel A or channel A and channel B at low speed
(shaft < P0492)
r0949 = 7 means excessive flux variance which may cause motor instability - possible due to
encoder loss.
CAUTION
Take care that signal loss on the inverted channels A and B is not observed by the inverter.
Remedial action on fault condition
Should the encoder give a fault message F0090 the following remedial action should be
performed:
1. Check that an encoder is fitted. If the encoder is not fitted, set P0400 = 0 and select
SLVC mode (P1300 = 20 or 22).
2. Check the connections between the encoder and the inverter.
3. Check the encoder is not faulty (select P1300 = 0 and run at a fixed speed then check the
encoder feedback signal using r0061). Check for correct magnitude and direction of
speed.
4. Increase the encoder loss threshold in P0492.
5. Increase encoder low speed loss detection delay in P0494.