Pv 800 power off notification to plc

Hello,

I have a piece of a equipment that has a Panel View 800 (2711R-T4T) HMI, Micrologix 1400 (series B), and some physical control buttons.

The physical buttons and switches are in the wrong orientation for the operator to operate in most cases so I installed the PV 800 in a more operator friendly location for them to control the equipment. I have used the Current Screen Number Global Connection in the HMI to tell the PLC which screen is active. What I wanted to do is that if the HMI loses power or it's program is unloaded it would place a 0 in that global connection value and the operator can still use the physical switches. There are a couple 3 position switches that make it hard to run in parallel in my ladder logic.

Can someone help me find a way to notify my PLC that my HMI is powered off and the program is unloaded?

Thanks!

I'm not too familiar with the PV, however, have you thought about a sort of heartbeat, i.e. read a bit or word from the plc that is changing, reflect this back in another bit/word to the PLC, so if the reflected word did not change within a time frame there is loss of communications

+1 parky
http://www.plctalk.net/qanda/showthread.php?t=75078

The above thread may help you out with the heartbeat.
Regards,

your issue with a heartbeat is going to be that the global connections tags from the PV800 only update every minute. So you're pretty limited there in terms of what you can do on those PV800's and a heartbeat. Typically I would setup a heartbeat with a PVP by using the global connections tag for the PVP's seconds and then some logic in the PLC to make sure that value is continuing to change over a set period of time, if it doesn't, there has been a comms loss and an alarm will be triggered. Again, you can do this method with a PV800, the issue youll have though is that the alarm period would have to be at least 60 seconds because thats how long it takes for the PV800 to update its time specific tags in the global connections.

I did a project with a MicroLogix 1400 and a PanelView Component a few months ago where I wanted to know if the PanelView had been shut off or disconnected quickly.

I wrote a repeating MSG instruction in the MicroLogix to read the PanelView's Identity Object with a CIP Generic message. If the message timed out (I used manual timeout logic) I was able to have the system react.