F35151 — TM54F: Discrepancy error

F35151 is raised by the TM54F Terminal Module when a safety-relevant terminal is in a discrepant state: the failsafe digital inputs (F-DI) or the failsafe digital outputs (F-DO) show a different state for longer than the discrepancy time parameterized in p10002. On S120 and S150 the manual additionally names too many switching operations within one monitoring cycle p10002 as a trigger. The fault value in r0949, interpreted hexadecimal, identifies the affected terminal. If several discrepancy errors occur consecutively, the fault is signaled only for the first error; the further errors are analyzed in the commissioning tool.

• The safety-relevant input terminals (F-DI) or output terminals (F-DO) of the TM54F hold a different state for longer than the time parameterized in p10002.
• Per the S120/S150 manual: too many switching operations were carried out within a monitoring cycle p10002.

1. Read the fault value in r0949 hexadecimal (yyyyxxxx): bits 0–9 of xxxx identify the discrepant F-DI, bits 0–3 of yyyy the discrepant F-DO.
2. Check the wiring of the corresponding F-DI (contact problems).
3. 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 must have a longer time between them, and the time interval between each signal edge at an F-DI must be at least equal to the discrepancy time before the input is switched again.
4. Because only the first of several consecutive discrepancy errors is signaled, evaluate the input states and output states of the TM54F using the commissioning tool — all discrepancy errors are displayed there — and compare p10051 and p10052 of the TM54F master and TM54F slave for discrepancy.
5. For cyclic switching operations at the F-DIs, adapt the discrepancy time p10002 to the switching frequency: it must be less than half the period tp of a switching operation minus the actual discrepancy time td, must be greater than td, and must be no less than p10000. td is the discrepancy time that can actually occur with a switching operation (in ms) and must correspond to at least 1 SI sampling cycle; tp is the period for a switching operation in ms.
6. If a debounce time is parameterized (p10017 > 0), it directly specifies the shortest possible discrepancy time and must always be set less than the discrepancy time; the time between two fast switching pulses should be longer than the discrepancy time plus p10017. The discrepancy time is accepted only as a whole SI sampling time — round up or down to an integer multiple of the SI sampling time; it must be at least r10003.
7. Check the setting against the manual's example: at an SI sampling cycle of 12 ms and a switching frequency of 110 ms (p10017 = 0), p10002 <= 110/2 ms - 12 ms = 43 ms --> rounded-off, the following is obtained p10002 <= 36 ms.
8. Observe the basic secondary condition: the discrepancy time of the F-DIs must always be longer than the longest SI sampling time of all drives that use Safety Integrated with TM54F (p9780/p9500).

• The drive stores the fault value in r0949; interpret it hexadecimal in the form yyyyxxxx hex.
• xxxx — the safety-relevant input terminals F-DI indicate a discrepancy: Bit 0: Discrepancy for F-DI 0 … Bit 9: Discrepancy for F-DI 9.
• yyyy — the safety-relevant output terminals F-DO indicate a discrepancy: Bit 0: Discrepancy for F-DO 0 … Bit 3: Discrepancy for F-DO 3.

• p10002 — SI Motion F-DI changeover discrepancy time (processor 1): the fault is raised when a terminal holds a different state longer than this time; adapt it to the switching frequency at the F-DIs.
• r0949 — fault value: read it hexadecimal to see which F-DI (bits 0–9 of xxxx) or F-DO (bits 0–3 of yyyy) shows the discrepancy.
• p10006 — SI Motion acknowledgment internal event F-DI (processor 1): the safe acknowledgment after the cause has been resolved is carried out here and is required before the discrepancy is completely acknowledged.
• p10017 — SI Motion digital inputs debounce time (processor 1): if > 0, it directly specifies the shortest possible discrepancy time and must always be set less than the discrepancy time.
• p10000 — SI TM54F communication clock cycle: the discrepancy time must be no less than p10000, and td must correspond to at least 1 SI sampling cycle (see p10000).
• p9500 — SI Motion monitoring clock cycle of the Control Unit: named together with p9780 as the reference for the longest SI sampling time of all drives that use Safety Integrated with TM54F, which the discrepancy time must always exceed.

The fault itself is acknowledged immediately. For a discrepancy at an F-DI this normal acknowledgment is not complete on its own: Discrepancy errors in the failsafe digital inputs (F-DI) can only be completely acknowledged if, after the cause of the error was resolved, safe acknowledgment was carried out (see p10006). Until this safety acknowledgment has been carried out, the corresponding F-DI stays in the safe state internally.