FactoryTalk View ME: turn off a maintained PB with another button

[markus506]

Hi all,

Learning the FTView ME software and have come across an issue: I have a latched process start button, a stop button and a pause button. Stop is momentary and Pause is maintained. If pause has been pushed, then Stop is pushed, I want Pause to become 'unpushed' or reset. I tried switching its State settings to value control, but it still behaves like a state control, i.e. once pushed, and clearing the tag in the PLC, the button still behaves as pushed.

Am I missing something with this? Is this even possible?


Thanks!

 

[dmargineau]

You could implement your logic approach by using a Latched push button or an Interlocked push button instead of a Maintained one.

The former uses its Handshake connection to "unlatch" its switched state while the latter uses buttons within the same group (writing to the same CPU tag) to switch their commanded states.

 

[markus506]

You could implement your logic approach by using a Latched push button or an Interlocked push button instead of a Maintained one.

The former uses its Handshake connection to "unlatch" its switched state while the latter uses buttons within the same group (writing to the same CPU tag) to switch their commanded states.

Thank you for the response. I guess the only difference is, and I didn't state this previously, is that I still want the Pause to behave as a maintained PB, i.e push Pause, changes color, and text changes to Resume. Push again to come back to Pause. I just need a way to change states back if another button is pressed.

 

[dmargineau]

I am afraid that you will need to implement this functionality at controller application level and this should be an approach I would recommend for any HMI application development.

Trying to overlap HMI objects' functionality and/or getting into elaborate logic inside an HMI application will result in frustration and non-conformance when field deployed.

The CPU controller has exponentially more tools and capacity to satisfy any logic requirements than a Graphical User Interface.

 

[markus506]

I am afraid that you will need to implement this functionality at controller application level and this should be an approach I would recommend for any HMI application development.

Trying to overlap HMI objects' functionality and/or getting into elaborate logic inside an HMI application will result in frustration and non-conformance when field deployed.

The CPU controller has exponentially more tools and capacity to satisfy any logic requirements than a Graphical User Interface.

I understand what you're saying. I tried this using the aforementioned maintained PB and the momentary PB. When the maintained PB was pushed and the XIC was true, pressing the momentary PB would clear this XIC. However, the maintained PB would not return to State 0, even after selecting the Value setting in the state control. Perhaps being new to all of this, I am approaching this the wrong way....

 

[dmargineau]

I understand what you're saying. I tried this using the aforementioned maintained PB and the momentary PB. When the maintained PB was pushed and the XIC was true, pressing the momentary PB would clear this XIC. However, the maintained PB would not return to State 0, even after selecting the Value setting in the state control. Perhaps being new to all of this, I am approaching this the wrong way....

Don't get discouraged, it will get better eventually.

Generally, HMI devices are not capable of laborious logic implementations; that's the CPU's job.

I personally dislike any non-Momentary push buttons; the HMI communications nature could cause major functionality issues when the terminal's decision making is extended to more than one update cycle.

 

[markus506]

Don't get discouraged, it will get better eventually.

Generally, HMI devices are not capable of laborious logic implementations; that's the CPU's job.

I personally dislike any non-Momentary push buttons; the HMI communications nature could cause major functionality issues when the terminal's decision making is extended to more than one update cycle.

Thanks for the support! It is much appreciated.

I ended up solving the problem...on the maintained PB tag, I just had to attach the same Value tag to the Indicator tag. After, when clearing the XIC in the PLC with the Stop button, things functioned as expected. Thanks again for the help!

 

[VAN]

Thanks for the support! It is much appreciated.

I ended up solving the problem...on the maintained PB tag, I just had to attach the same Value tag to the Indicator tag. After, when clearing the XIC in the PLC with the Stop button, things functioned as expected. Thanks again for the help!

That sounds like a huge pain to troubleshoot.

If you are looking at the code and for whatever reason the PB remains on (stuck pixel who knows) and the clear pushbutton doesn't work...

What about if the tag gets stuck active and the hmi comms are lost?

 

[arlenjacobs]

Thanks for the support! It is much appreciated.

I ended up solving the problem...on the maintained PB tag, I just had to attach the same Value tag to the Indicator tag. After, when clearing the XIC in the PLC with the Stop button, things functioned as expected. Thanks again for the help!

That's the way to do it in FTViewME. Asssign the same tag for both Value and Indicator; along with the state control.
That will only fix the visual state of the push buttons on the HMI.

That sounds like a huge pain to troubleshoot.

If you are looking at the code and for whatever reason the PB remains on (stuck pixel who knows) and the clear pushbutton doesn't work...

What about if the tag gets stuck active and the hmi comms are lost?

Do you mean for the momentary PB? That would be a problem for any HMI, unless there is PLC code to detect if the HMI is lost.
Ex. The state control should always be in the PLC, and all troubleshooting of that state control in the PLC code.
I think that's a different problem; which is still relevant here, but would be PLC code.

The OP question is really about how the pushbuttons look on the HMI. In FTViewME they do not (by default) change how they look to match changes in the PLC tag.
You have to manually set that up, the way that Markus did.

 

[WEST]

Stop / Start or On / Off or Open / Close single use buttons

Hello all,

Not that I recommend as I do use momentary and latches however if need be a quick and dirty method.

1. use a maintained button for Open / Start / On states

Set the bit address for the button to ... xxxx PLCTAG
in the STATES TAB

Set State0 General Value as [1]
Set Caption to "Open / Start / On" or set picture

Set State1 General Value as [1]
Set Caption to "Open / Start / On" or set picture (same as above)

Set Error (only after debugged)
Set Caption to "Open / Start / On" or set picture (as above) as the error generated will be that the state is "0" and it doesn't match any of the listed above states.

Viola an Open / Start / On State button only.

1. use a maintained button for Closed / Stop / Off states

Set the bit address for the button to ... xxxx PLCTAG
in the STATES TAB (exact same tag as above)

Set State0 General Value as [0]
Set Caption to "Closed / Stop / Off" or set picture

Set State1 General Value as [1]
Set Caption to "Closed / Stop / Off" or set picture (same as above)

Set Error (only after debugged)
Set Caption to "Closed / Stop / Off" or set picture (as above) as the error generated will be that the state is "1" and it doesn't match any of the listed above states.

Viola an Closed / Stop / Off State button only.

This does remove all issues of "loss of communication" weird change of states etc., I have tested this and works I may even implement full time as it really is simple and reduces "code" and resources in PLC. This is highly important on Lean Mean Code work.

In Grace,


Michael