# Does an OPC-tag only change when a value is received or could change based on other parameters?

**URL:** <https://forum.inductiveautomation.com/t/does-an-opc-tag-only-change-when-a-value-is-received-or-could-change-based-on-other-parameters/106396>\
**Category:** Ignition\
**Tags:** ignition81\
**Created:** [May 19, 2025, 10:20am UTC](https://forum.inductiveautomation.com/t/does-an-opc-tag-only-change-when-a-value-is-received-or-could-change-based-on-other-parameters/106396 "2025-05-19T10:20:31Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![danielps1818](https://avatars.discourse-cdn.com/v4/letter/d/ecae2f/32.png) [@danielps1818](https://forum.inductiveautomation.com/u/danielps1818)\
**Post date:** [May 19, 2025, 10:20am UTC](https://forum.inductiveautomation.com/t/does-an-opc-tag-only-change-when-a-value-is-received-or-could-change-based-on-other-parameters/106396/1 "2025-05-19T10:20:31Z")

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Maybe is a silly question. But we are getting random zeros from a value. The machine vendor said that that should not happend... But is happening... We are trying to see if it's a problem from Ignition.

Our current setup is an OPC-tag with an historian setting on change with the deadband in off mode. There we get random zeros.

My question is: **Is this directly binded with what is being sent from the machine?**  
If the answer is Yes, then we know that the machine is sending us random zeros, if not, we will have to continue looking.

Thanks in advance!

_PS:_ The quality when we get a zero is good, so it does not look like a connection problem.

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**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\
**Post date:** [May 19, 2025, 11:55am UTC](https://forum.inductiveautomation.com/t/does-an-opc-tag-only-change-when-a-value-is-received-or-could-change-based-on-other-parameters/106396/2 "2025-05-19T11:55:43Z")

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You should open a support ticket. You will likely be asked to turn off encryption for that connection so that you can get a meaningful wireshark capture. (I suspect you really are getting a zero, due to sloppy PLC code. Or perhaps a bug in that server's OPC implementation.)