$Critical IO Error (ST148) How to trace cause?

[ERokc]

I can Re-initialize IO and it clears but I would like to know which module is causing the error and why.
H2-DM1E, PLC is in RUN but nothing on the machine is moving and I get a audable DING on the PC and a red error at the Designer bottom screen.  PLC goes to PROGRAM and will not RUN until a power off or re-init then it will RUN.  This has happened three times during editing instruction in Designer.

Any way to tell who's got the problem?

[BobO]

Critical I/O errors are the result of a module not responding with the proper module ID during a normal input scan. Could be a flaky backplane, backplane connection, or module. The specific name alludes me...probably something like $LocalIOMaster...but there is a structure that contains a list of bit masks for each slot. Check the .Slots0_31 member to see which slot(s) are bad.

For DmD 1.1, we have added a very nice utility that displays all of this information automatically. It is much, much easier to use...and will be out shortly.