Studio 5000 Local Usage Tag

Hello
I attached a screen shot from a AB Control logix PLC running Studio 5000 software.

The issue that I'm having is that I cannot get my SCADA Wonderware software to toggle the "Reset_PB" input below.

I noticed the "Usage" tab for the tag it was set to "Local"
This can be changed to either one of these

• 
  Local Tag
  Input Parameter
  Output Parameter
  InOut Parameter
  Public Parameter

Would this affect the Wonderware software from toggling the Reset_PB input?

Thanks for helping

hard to see at the resolution you posted – but it looks like your tag Reset_PB is an alias (just annother name) for the tag Local:1:I.Data.1 ...

if so ...

then every time the input module located in Slot 1 gets refreshed (think: RPI rate, etc.), the module will write the appropriate ONE or ZERO "field" status into the bit location ...

in simplest terms, your SCADA software might indeed be toggling the bit for you – but you can't see the change - because the input module is updating the bit right back to the actual "field" status (current yes - or current no) within a few milliseconds or so ...

TIP: you might try creating a brand new bit/tag - and aim the SCADA at that one ... then modify your code to use that new tag to activate/deactivate your logic ...

Thanks Ron
Just wanted to make sure I understand about creating a new tag. When I create a new tag, I would still have to point it to input Local:1:I.Data.1... right?
or would I do something different?

Thanks for your explanation

thanks,

nope ... you can just "point it" at NOTHING ... you'll be setting up a brand new location in the controller's memory - and the SCADA can write directly into that location ...

try it - you'll like it ...

I would create a new tag in the existing PLC code and put it in parallel with the "Local" input alias bit in the ladder logic.

Just branch around the existing reset tag and create a new tag in the PLC logic for the WonderWare bit. Give it a meaningful name. But for sake of conversation, call it WonderWareResetPbInput.

Make sure it is a controller scoped tag. When it's controller scoped, it's slightly easier to reference it in WonderWare.
If it's not controller scoped, you need to drill down a bit more in the tag reference in WonderWare.

In WonderWare create a new Discrete Value pushbutton and point it at your new RSLOGIX tag.

Sometimes, with my version of WonderWare, I need to redeploy the CIP object before WonderWare see's the new tag.

Another (possibly better) approach I tend to use is to create two tags in RsLogix.

One is the wonderware input, and another is the output bit.

Add a rung in your RsLogix using the WonderWareResetPbInput for the input and create another tag called WWResetPb for the output. That's all there is in that rung.

Now, use the WWResetPb(output) to branch around the local reset pushbutton.

The reason I do this is because some of our techs can only access the PLC code, and not the WonderWare program.

This allows them to "jump out" or "disable" the WonderWare logic in the PLC, if needed. OBVIOUSLY bypassing a RESET would not be logical.

The point being, you can now process the input and add functionality of the output in the PLC without modifying the WonderWare program.

There is a lot of discussion on this forum about using HMI inputs and the issue with losing communications with the HMI, where bits get latched on, or hold there last state. It's an interesting topic and I personally need to experiment more with it, and I recommend you do the same.

As for your original question, add a counter in the PLC logic, with a ONS, with your SCADA tag to see if the the Reset_PB
is actually working.

You seem to be trying to use the SCADA to toggle a physically wired input. Every scan the PLC is looking at the physically wired input. The SCADA "might" interupt the input status for one scan, but the subsequent scan will revert to the actual status of the hard-wired input. Use a seperate HMI/SCADA tag.

Thank you for your explanation
That’s exactly what I’m trying to do is use the SCADA to toggle a physical input.

I will do as you have explained.

Thanks again for all the help