Hi there,
Here is what I have:
1 - A PI Tag called myDT, which is a string that is saved to PI via a PLC.
2 - A PI Tag called LiveValue which is a float that monitors a value changing in the PLC
3 - A PI Tag called HistoricalValue which is a float that is an output tag, that pushes a value back to the PLC
4 - A PerformanceEquation called PE thatis used as the source tag for #3, and has an equation of TagVal('LiveValue','*')
What happens is that the LiveValue is saved from the PLC, the performance equation is triggered to map its value in to HistoricalValue and that is pushed back to the PLC. All of this works fine.
I want to change it so that the expression TagVal('LiveValue','*') in the performanceEquation so that the * actually resolves to the value in the tag myDT. So when myDT = 'Sept 21, 2010 6:45:00' the expression would be TagVal('LiveValue','21-Sep-10 6:45:00'). I am having no luck using anything other than things like '*' or '*-2m' as the second parameter. Can I not use timestamps in this field? IF not are there any other options? I could also use something like '*-8s' if I caould make the -8 dynamic based on a tag.
Please help,
Jamie
