I have a number of analog I/O & calculation tags configured with advanced alarms.

I'd like some of these alarms to write to the PLC, setting a bit when they are active then resetting that bit when they are inactive.

Can this be configured? If so, how?

There are a number of ways to do this, one simple way would be to made an IO and Calc tag configured as a digital calculation. Then you can set the calculation to an expression similar to:

[AlarmTagName] == 1 ? 1 : 0

Set the address to your PLC address you wish to write to a 1 or 0 depending on the alarm condition.

Thank you so much. This is going to save me so much work.

Not exactly sure how VTScada name their alarm tag names but I think I can figure this out. If it's not explained in the help I'll reply with a follow up question.

So it turns out I don't have actual alarm tags. I have an analog I/O & calculation tags with advanced alarms configured from it's tab.

You mentioned there is a number of ways this can be done & I see you work for VTScada. Could we chat over the phone about this? Perhaps one of the other ways that came to mind for you be a better when I apply it.

No need Dave, I found a way to do this that works well with what I've built.

I'm glad you figured out a way to make this work in your system.

Learn about using tag values in expressions here: https://www.vtscada.com/help/Content/Scripting/Expressions/UseTagValues.htm

Note that you can also use tag properties and not just their values, these options are not well documented in the help files but for example [TagName]\Description would return the tag description. There are ways to get all of the available properties of each tag type but you typically have to create a custom tag type to easily see those options. I can't remember the alarm references but they are something like [Tag Name]\HighAlarmActive. IF I get a chance tonight, I'll update this will a list of the available properties for the I/O and Calc tag in VTScada 12.0.50

Yep, that's exactly what I did. My analog I/O & calculations tag's called reading.

The syntax is [reading]\HighAlarmActive.

No need to reply here with a list of avilable properties but if that could be added to the help this would be great. I had to use the source debugger to get the property names but I found that tool hard to use.

Here are some commonly used properties for the I/O and Calc Tags

[TagName]\Name
[TagName]\Description

[TagName]\HighHighAlarmActive
[TagName]\HighAlarmActive
[TagName]\LowAlarmActive
[TagName]\LowLowAlarmActive

[TagName]\AlarmActive
[TagName]\DigitalAlarmActive

You can learn to find all of the properties for any tag by reading the help files here: https://www.vtscada.com/help/Content/Scripting/Expressions/UseTagProperties.htm?tocpath=Scripting%7CExpressions%7C_____8

Does anyone else get gibberish when they reference the equipment type or description properties in an expression?

For some properties like Name, I get the value I expect, and others return strange values.

Yes I have.

Since VTScada 12, when multi language support was introduced, text properties refer to the Phrase Key rather than the phrase itself. You'll need to use a call such as \GetPhrase(..\Description) to get the string you are looking for.

You can learn more about this and view some examples here: https://www.vtscada.com/help/Content/Pro_Functions/GetPhrase.htm