RMA
Member
Out of 21 (near identical) Modules in this system, I have only one available to test on. On start-up I check to see which Modules are not available and then prevent these being selected. I also disable them using SFC12.
Most of the time I check whether a Module is selected before accessing it, so there is no problem. However, because the outputs of the Modules (Electrical pulses of up to 43 kA at 24 kV) are connected in parallel to one of four so-called Collectors by motor-driven switches which can also be switched by hand, it is always necessary to check that the switches of non-selected Modules are open before triggering a pulse. Since during the commissioning phase it is more than likely that a Module will be physically present but not switched on, the auto-detection of available Modules is not a sufficient safety precaution, so I must always check the state of all Modules.
Unfortunately, when I enable the S/W to do this despite having disabled the Modules I get flooded with I/O faults which pushes the cycle time up over 1 second and the CPU goes into STOP. I don't know what the maximum cycle time is, but I've set it at 500 ms at present (to try and avoid the problem) and I don't really want to increase it any further.
I've checked the state of the Modules using SFC12 Mode 0 and they all report that they are disabled. The Help file for SFC12 states quite explicitly that after being disabled, the DP-Master no longer accesses the Slaves and that the Process Image is updated with "0"s.
One thing that is a bit strange is that as long as I don't call the monitoring Block, there is no problem which implies that the Process Image update is not normally attempting to access the DP-Slaves that are disabled. The second peculiar fact is that I get exactly the same problem if I enable my general error checking S/W, even though in this case, the Modules are only accessed if they are selected.
All suggestions of how to solve the problem or locate its source would be very welcome.
Most of the time I check whether a Module is selected before accessing it, so there is no problem. However, because the outputs of the Modules (Electrical pulses of up to 43 kA at 24 kV) are connected in parallel to one of four so-called Collectors by motor-driven switches which can also be switched by hand, it is always necessary to check that the switches of non-selected Modules are open before triggering a pulse. Since during the commissioning phase it is more than likely that a Module will be physically present but not switched on, the auto-detection of available Modules is not a sufficient safety precaution, so I must always check the state of all Modules.
Unfortunately, when I enable the S/W to do this despite having disabled the Modules I get flooded with I/O faults which pushes the cycle time up over 1 second and the CPU goes into STOP. I don't know what the maximum cycle time is, but I've set it at 500 ms at present (to try and avoid the problem) and I don't really want to increase it any further.
I've checked the state of the Modules using SFC12 Mode 0 and they all report that they are disabled. The Help file for SFC12 states quite explicitly that after being disabled, the DP-Master no longer accesses the Slaves and that the Process Image is updated with "0"s.
One thing that is a bit strange is that as long as I don't call the monitoring Block, there is no problem which implies that the Process Image update is not normally attempting to access the DP-Slaves that are disabled. The second peculiar fact is that I get exactly the same problem if I enable my general error checking S/W, even though in this case, the Modules are only accessed if they are selected.
All suggestions of how to solve the problem or locate its source would be very welcome.