SINUMERIK 810D/840D: alarm 16927 channel 1 action change to program mode at active interrupt treatment not allowed
What might be causing sporadic Alarm 16927?
The alarm can be generated by an incorrect setting of machine data 11602 ASUP_START_MASK (ignore stop reasons for ASUB) or by an interlocking in the PLC.
Notes regarding bit 3 of machine data 11602
If an ASUB is automatically started from the JOG mode, then the user may stop in the middle of the ASUB program. The JOG operating mode is continuously displayed to the user. In this situation, the user can jog as BIT 3 is set. Without bit 3, this is not possible. In this situation, the mode change is interlocked with Alarm 16927. The user can continue the ASUB program using the "start" key. It goes without saying that the user cannot jog as long as the ASUB program is running. The user may jog again once the ASUB program has ended.
The following function is ONLY implemented in single-channel systems and it is only effective for ASUBs that were activated from the interrupted program state (channel status reset). The function automatically disappears if only one additional channel is added to the machine data.
You can find more detailed information in Manual "SINUMERIK, SIMODRIVE, detailed MD description (AMD)" in entry ID: 28821007.
A set operating mode change inhibit – and if the PLC deletes the selected operating mode – can also generate Fault 16927 if an ASUB with RESET or M17 in JOG is to be exited. The ASUB is started from JOG/RESET, and attempts to switch back to JOG. The PLC initiates a new operating mode change before a switch can be made to JOG.
Remedy: wait until the ASUB has ended before changing the operating mode.
Note: the FC-9 provides the "DONE" interface bit for this purpose.