Host Engineering Forum

General Category => Do-more CPUs and Do-more Designer Software => Topic started by: Henryp on October 03, 2018, 07:29:25 PM

Title: Using $LastScan to see if a DM is in run mode.
Post by: Henryp on October 03, 2018, 07:29:25 PM

Hi,
I'm using $LastScan to reset a Modbus coil so I can read if my PLC is in run mode. The PLC had an I/O error and the coil didn't reset. Does $LastScan not go true on an I/O fault? Attached is a screen print.
Thank you

Title: Re: Using $LastScan to see if a DM is in run mode.
Post by: BobO on October 04, 2018, 12:23:47 AM

I/O faults are fatal errors, and currently all fatal errors shut down hard. I guess there really is no reason we can't treat I/O errors a little more gently though, and do the $LastScan.