ADC Lockup

[skj1402]

I'm using a resistive networked matrix keyboard, which is interfaced to 3 of the ADC inputs of a 1616 PLC, and most of the time the configuration works well. But it seems that when I initiate either one of two sequencers in my program, all three ADC ports just 'freeze' for no apparent reason!
Using the 'Online monitoring' facility I can easily monitor the ADC input levels, and these are seen to just 'freeze' when I activate a sequencer from the keyboard, and therefore the keyboard becomes inactive and useless. However, when I advance the sequencer via the 'Online monitoring' simulator, everything then jumps back into life???

Can you please throw some light on why this is happening? Is this maybe a bug within the PLC's operating system?  Any assistance would be much appreciated. Thanks.

[support]

There are no known bugs as per your description. Note that the ADC #n channel value is only updated when the corresponding ADC(n) command is executed. It should be because your program did not execute the ADC(n) command at certain point and therefore the ADC value doesn't change anymore at that state. Once you advance sequencer you may have made it go to the next sequence where the ADC(n) is being read and therefore it appear live again.

[Steve Jones]

I appear to have resolved the problem simply by relocating the ADC handling Cf from table position 1 to position 32 in the Cf listing.  Why has this resolved the problem? I don't know, but it now works!!  Any theories as to why this is so, would be most welcomed!

[support]

I don't think it has anything to do with the position of the Custom function in the CF table. It is likely something you did in your program that make a difference when you shift your function around in the program. The problem may not have gone away completely if you don't know what was the reasons, since the very logic that caused the apparent freeze of ADC reading may still surface later (we hope not