C01770 — SI Motion P1 (CU): Discrepancy error of the fail-safe inputs/outputs

C01770 is a safety message of the Safety Integrated motion monitoring on processor 1 in the Control Unit: the safety monitoring channel has identified a discrepancy error at the failsafe digital inputs and, where the converter description includes outputs, at the failsafe digital outputs (F-DI/F-DO). An affected signal has shown a different state for longer than the discrepancy time parameterized in p10002/p10102; the S120/S150 description additionally names too many switching operations within a monitoring cycle of p10002. The G120 description covers the failsafe digital inputs only. If several discrepancy errors occur consecutively, the drive signals only the first one.

• The failsafe digital inputs — and, in the descriptions that include them, the failsafe digital outputs (F-DI/F-DO) — show a different state for longer than parameterized in p10002/p10102; on the G120 only the F-DI are named.
• In the S120/S150 description: too many switching operations took place within a monitoring cycle of p10002.

1. Check the wiring of the F-DI for contact problems.
2. If the wiring is correct — for example there is no wire breakage — check whether the switching frequency at the F-DI is too high and must be reduced: switching pulses need a longer time between them, and the interval between each signal edge at an F-DI must be at least equal to the discrepancy time before the input is switched again.
3. For cyclic switching, adapt the discrepancy time in p10002/p10102 to the switching frequency: the period of a cyclic switching pulse must be less than half of the discrepancy time (round down if necessary), the time between two fast switching pulses should be longer than the discrepancy time (round up if necessary), and the discrepancy time must be at least p9500 — the G120 description requires at least 12 ms — and a whole multiple of the SI sampling time.
4. If a debounce time is parameterized (p10017 > 0), the shortest possible discrepancy time is directly specified by the debounce time; the time between two fast switching pulses should then be longer than the discrepancy time plus p10017, and the debounce time must always be set less than the discrepancy time.
5. Example from the manual: with a 12 ms SI sampling cycle and a switching frequency of 110 ms (p10017 = 0), the maximum is p10002 <= 110/2 ms - 12 ms = 43 ms, rounded off to p10002 <= 36 ms, because the value is only accepted as a whole multiple of the SI sampling time (on the G120, of 12 ms).
6. Basic secondary condition: where Safety Integrated is used with TM54F, the discrepancy time of the F-DIs must always be longer than the longest SI sampling time of all drives involved.

• The message value is the fault value in r0949, interpreted bitwise binary as yyyyxxxx bin.
• xxxx — discrepancy error for the failsafe digital inputs (F-DI): Bit 0 = F-DI 0, Bit 1 = F-DI 1, and so on.
• yyyy — discrepancy error for the failsafe digital outputs (F-DO): Bit 0 = F-DO 0, and so on.
• The G120 description decodes only the F-DI bits (Bit 0 = F-DI 0, Bit 1 = F-DI 1, ...).

• p10002 — SI Motion F-DI changeover discrepancy time (processor 1): the discrepancy time whose exceeding raises this message; adapt it here for cyclic switching.
• p10102 — SI Motion F-DI changeover discrepancy time (processor 2): the processor-2 discrepancy time named in the cause alongside p10002.
• r0949 — fault value: read it bitwise binary to identify the F-DI or F-DO with the discrepancy error.
• p10006 — SI Motion acknowledgment internal event F-DI (processor 1): parameter named for the safe acknowledgment of an F-DI discrepancy error via PROFIsafe once the cause is resolved.
• p9507 — SI Motion function specification (Control Unit): bit 0 (p9507.0) activates the "Extended message acknowledgment" function, which restricts safe acknowledgment for an STO/SS1 F-DI in the fail-safe state.
• p9500 — SI Motion monitoring clock cycle (Control Unit): the SI sampling time; the discrepancy time must be at least p9500 and a whole multiple of it.
• p10017 — SI Motion digital inputs debounce time (processor 1): if set greater than 0, it directly specifies the shortest possible discrepancy time and must stay below the discrepancy time.

A discrepancy error of an F-DI is acknowledged safely, via an F-DI or via PROFIsafe, and only once the cause has been resolved: safe acknowledgment must have been carried out (p10006, acknowledgment via PROFIsafe, extended message acknowledgment). As long as safety acknowledgment has not been performed, the affected F-DI is held internally in the safe state. With the "Extended message acknowledgment" function active (p9507.0), the following applies: If the F-DI assigned for STO or SS1 is in a failsafe state due to a discrepancy error, then when deselecting via this F-DI, safe acknowledgment can no longer be executed.