# Advice on the best way to count the hours to set point of an opc tag

**URL:** <https://forum.inductiveautomation.com/t/advice-on-the-best-way-to-count-the-hours-to-set-point-of-an-opc-tag/33558>\
**Category:** General Discussion\
**Created:** [March 31, 2020, 5:15pm UTC](https://forum.inductiveautomation.com/t/advice-on-the-best-way-to-count-the-hours-to-set-point-of-an-opc-tag/33558 "2020-03-31T17:15:21Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![DAVID.RIISKA](https://avatars.discourse-cdn.com/v4/letter/d/ed8c4c/32.png) [@DAVID.RIISKA](https://forum.inductiveautomation.com/u/DAVID.RIISKA)\
**Post date:** [March 31, 2020, 5:15pm UTC](https://forum.inductiveautomation.com/t/advice-on-the-best-way-to-count-the-hours-to-set-point-of-an-opc-tag/33558/1 "2020-03-31T17:15:21Z")

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I’m looking for a way to count the amount of hours it takes for my industrial furnace to get to the temperature set point. I have the temperature as a opc tag but im not even sure where to start. I want to start the count at 10 am and count the hours it takes to get from its current temp to 2350 deg F.  
I’m pretty new to ignition and programming in general.  
Any pointers would be helpful.  
Thanks

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**Author:** ![thowsham](https://avatars.discourse-cdn.com/v4/letter/t/c6cbf5/32.png) [@thowsham](https://forum.inductiveautomation.com/u/thowsham)\
**Post date:** [April 1, 2020, 12:11am UTC](https://forum.inductiveautomation.com/t/advice-on-the-best-way-to-count-the-hours-to-set-point-of-an-opc-tag/33558/2 "2020-04-01T00:11:17Z")

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(1) Read a “Go” Tag (Run furnace)  
(2) Note in Ignition what time the “Go” Tag went True  
(3) Note in Ignition what time the “Go” Tag went False  
(4) Runtime = (3) - (2)

There’s Python scripting to help withe Date/time subtraction

It would be a lot easier in PLC Logic to do and just read the tags (If you have permission to add a bit of logic that is) 😉