# OPC "Start Button" in Perspective

**URL:** <https://forum.inductiveautomation.com/t/opc-start-button-in-perspective/70396>\
**Category:** Ignition\
**Tags:** ignition81, vision, perspective\
**Created:** [February 28, 2023, 12:51am UTC](https://forum.inductiveautomation.com/t/opc-start-button-in-perspective/70396 "2023-02-28T00:51:26Z")\
**Posts on this page:** 1\
**Showing post:** 2

<div class="post-metadata">

**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:** [February 28, 2023, 1:56am UTC](https://forum.inductiveautomation.com/t/opc-start-button-in-perspective/70396/2 "2023-02-28T01:56:28Z")

</div>

The "set from Ignition/reset in PLC" pattern is problem for OPC subscriptions--the polling that occurs with random synchronization to the write operation. If you use `system.opc.write*()` to set the bit, and don't care about reading it, then the PLC reset paradigm is fine.

In other words, just don't use a tag.

---

_[View the full topic](https://forum.inductiveautomation.com/t/opc-start-button-in-perspective/70396)._