Access a function block parameter from SCADA?

[TheWaterboy]

Compactlogix PLC

I have a totalizator function block that totals flow. There are unusual circumstances where we pause flow momentarily and the logic causes the total top switch to the last total.

To make it more difficult to reach the totalizer is program scoped not controller scoped.

Is there a way to edit the "OldTotal" from HMI? The tag would be controller.program.functionblock.OldTotal. But when I tried to address it I was not able to reach it.

If I can't edit it, (its grey in the dialog box) there is no point so thats the important question.

 

[Mike_RH]

Which HMI product are you using?

 

[Mark-]

Hello,

For PeakHMI to access program variables the format is:

programName:functionBlockName.whatever.

The : is the important part.

 

[TheWaterboy]

This is iFix through Kepware. I'll check on the syntax, but I'm not sure if that field can even be written to.

 

[TheWaterboy]

Cant write to the tag OldTotal, Appperantly since it is an Output.
I can write to the current total and toggle that into place, but I may have to do this while the totalizer is in used and total is incrementing so that option is out.
Anyone know if this is even possible?

 

[TheWaterboy]

Got it figured... I can access and write to .OldTotal and any other parameter as long as the function block is globally scoped. Program scoped function blocks can't be reached even though Kepware will allow the address.

At least thats what I found so far.