Counting tag

Ignition
1

I have 2 tags.
1 is a bool and one is an expression.
I want the expression tag to keep track how many times the bool “becomes true”

Counter is something like:

if(hasChanged({[.]bool}) && {[.]bool} = 1, {[.]Counter} + 1, {[.]Counter} + 0)

This does not work and I really want to be able to track this over a thousand tags and don’t see the point of using a gateway script for this.
Any suggestions?

2

Try modifying your expression to look like the following. This is assuming your expression tag is called Counter:

if(hasChanged({[.]bool}) && {[.]bool} = 1,coalesce({[.]Counter}+1,0),coalesce({[.]Counter},0))
3

The only issue I see with that solution is the tag “Counter” value does not change to zero when reset.
I have tried 2 ways:

  1. Trying to write the value to zero from the designer.
    2)system.tag.writeToTag(“Counter”,0)

It does reset thou. You can refresh the tag database to show 0 or wait for the conditions to be true and it starts at 1 again.

If that is not an issue, then take solution should work. Otherwise, the Gateway Tag Change Script will work also.

Something like this:

def Count(b,c):
	import system
	bool = system.tag.getTagValue(b)
	Count = system.tag.getTagValue(c)
	if bool == 1:
		Count += 1
	else:
		pass
	system.tag.writeToTag(c,Count)

def ResetCount(c):
	import system
	system.tag.writeToTag(c,0)

Then just add the bool tag to the Gateway Tag Change Scripts to call the script.
app.Test.Count(“bool”,“Counter”)

Hope that helps.
Chris

4

[quote=“dave.fogle”]Try modifying your expression to look like the following. This is assuming your expression tag is called Counter:

[code]
if(hasChanged({[.]bool}) && {[.]bool} = 1,coalesce({[.]Counter}+1,0),coalesce({[.]Counter},0))

[/code][/quote]

I fixed this in the UDT but it looks like a question marked tag in each instance, I can write to it sometimes… it seems like it doesn’t like to equal itself in the else segment…

5

What version are you running because I’m not having a problem doing this in a UDT?

6

7.5.5
It is still giving me issues.
The tag has a question mark by it.

7

Thoughout my tag instances I have some Counters work. some have bad quality, some unknown quality.

8

One thing is that expressions propagate up the worst of the qualities contained in them. So it sounds like the counter is passing along its initial unknown quality. Try this:

forceQuality(if(hasChanged({[.]bool}) && {[.]bool} = 1,coalesce({[.]Counter}+1,0),coalesce({[.]Counter},0)),192)

You could do it around each reference to Counter, but this should be sufficient.

Regards,