A customer called me with a question about a SNAP PAC program. We didn’t write the program, it was someone internal who isn’t available anymore, but they knew we’ve used Opto products before so thought to ask us.
In their strategy they’ve got a level indicator that’s an analog input. When they view the I/O point, the XVAL shows the correct input value but the IVAL stays on 0. I read in the manual that that means the strategy is not reading/writing to the I/O point at that moment so the IVAL doesn’t get updated.
We searched for that input but couldn’t find it in the charts. It is in a PID though. When I asked him to bring up the PID, it showed that it was in Auto mode and Enable Comm was Yes. However, the Scan Counts was 0, it wasn’t counting up. The Scan Rate is 1 second. I don’t know much about PID’s but my guess is that something is preventing the PID from actually running which is why the input is not updating.
I also noticed that the Low Range and High Range were both set to 0 however in Config, the High Range is supposed to be 18 (i.e., 18 mA). I asked him to search for the PID and it appeared in one location which was to set the PID mode to auto so why is the High Range set to 0 and not 18?
Is there another reason why the PID wouldn’t be scanning? Is it related to the High Range being overwritten?