RSLogix5000 GSV

Hello all,

Could someone further explain how to use the GSV instruction in RSLogix.

For example, if I want to monitor the communication status between the PLC and a VFD, I have read that you can use a GSV. Class name module, and attribute name EntryStatus.

How am I supposed to know what the value that I receive back means? What value indicates communication is OK? Not OK?

Like I said above, this is just one example of the GSV. What if I wanted to monitor the status of the controller? What value indicates minor fault, major fault, program mode, run mode, etc.

Thanks for any information!

In the Studio 5000 Help file, the "GSV/SSV Objects" section is really good for both reference info and examples.

As a more general matter, I recommend two of the Programming Manuals:

1756-PM014: Logix 5000 Controllers Major, Minor, and I/O Faults

1756-PM015: Logix 5000 Controllers Information and Status Programming Manual

Doesn't matter what the value back means - read anything - if the MSG.DN is true, then you have comms, if the MSG.ER is true you haven't, monitor that to latch an alarm bit.

Here's one I use, it also includes to not to set the alarm bit if the drive is inhibited: