F31802 — Encoder 1: Time slice overflow

F31802 reports a time slice overflow in encoder 1: the processing for this encoder overran one of the clocked time slices the drive allocates to it. The two List Manuals describe the code identically for the G130, G150, S120 and S150 families, so the information below applies to all of them. Depending on how the drive is configured, the same condition can also be signalled only as an alarm, or even without an automatic reaction.

• A time slice overflow has occurred in encoder 1 — the encoder function needed more computing time than one of its time slices (fast, average or slow) provides.
• A special case of this code is a timeout when waiting for SYNO, for example after an unexpected return to non-cyclic operation.

1. Read the fault value in r0949 in hexadecimal to identify which time slice overflowed, or whether the SYNO timeout case is present.
2. Increase the current controller sampling time — this is the remedy the manuals give for this fault.
3. Look at p0491 if you want to check or change how the drive responds to this encoder fault.

• The drive stores the fault value in r0949, to be interpreted in hexadecimal as yx: y identifies the function involved (Siemens-internal fault diagnostics), x identifies the time slice involved.
• x = 9: time slice overflow of the fast (current controller clock cycle) time slice.
• x = A: time slice overflow of the average time slice.
• x = C: time slice overflow of the slow time slice.
• yx = 3E7: timeout when waiting for SYNO (e.g. unexpected return to non-cyclic operation).

• r0949 — holds the fault value of this fault; read it in hexadecimal to see which function (y) and which time slice (x) overflowed.
• p0491 — motor encoder fault response ENCODER: this is where the configured reaction to this encoder 1 fault is set, and the manuals cross-refer to it for this code.

Clear the fault by acknowledging it and then restart the drive; the message is one the drive accepts an acknowledgement for straight away, so no special reset sequence is needed. Once the current controller sampling time has been increased, the condition should no longer recur. Where the drive is configured to output this condition only as an alarm or without any reaction, the manuals state that no reaction takes place and no acknowledgement is required.