# Checking Gateway Logs for Tag/OPC Writes

**URL:** <https://forum.inductiveautomation.com/t/checking-gateway-logs-for-tag-opc-writes/14219>\
**Category:** Ignition\
**Created:** [May 5, 2017, 2:12pm UTC](https://forum.inductiveautomation.com/t/checking-gateway-logs-for-tag-opc-writes/14219 "2017-05-05T14:12:37Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![StoltzJordan](https://avatars.discourse-cdn.com/v4/letter/s/ce73a5/32.png) [@StoltzJordan](https://forum.inductiveautomation.com/u/StoltzJordan)\
**Post date:** [May 5, 2017, 2:12pm UTC](https://forum.inductiveautomation.com/t/checking-gateway-logs-for-tag-opc-writes/14219/1 "2017-05-05T14:12:37Z")

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Hello all,

Hopefully this is an easy one. In the Gateway logs, is there a way to see a history of ignition’s Tag/OPC writes? We have a particular address in a PLC that we are writing a nonzero value to. However, when we write the value to the address it first assumes a value of zero before taking on the value we are writing. I don’t believe this is an ignition issue, but would like to be able to prove it with some logs.

Any tips? Are there certain filters I should use, for example? We are using the latest release of Ignition.

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**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\
**Post date:** [May 5, 2017, 2:47pm UTC](https://forum.inductiveautomation.com/t/checking-gateway-logs-for-tag-opc-writes/14219/2 "2017-05-05T14:47:12Z")

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Are you writing from scripting? If so, which write function, `system.opc` or `system.tag`?

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<div class="post-metadata">

**Author:** ![StoltzJordan](https://avatars.discourse-cdn.com/v4/letter/s/ce73a5/32.png) [@StoltzJordan](https://forum.inductiveautomation.com/u/StoltzJordan)\
**Post date:** [May 5, 2017, 3:42pm UTC](https://forum.inductiveautomation.com/t/checking-gateway-logs-for-tag-opc-writes/14219/3 "2017-05-05T15:42:36Z")

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Kevin,

I’m using a mixture of system.tag and system.opc in different areas. The “0 flash” in question is occurring on a call to system.tag.writeAll(paths,values).

I also tried system.tag.writeSynchronous individually for the two tags in the path/values lists, but the same issue persisted.

I don’t mind switching to OPC writes if necessary, if those are more loggable.

Thanks!

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<div class="post-metadata">

**Author:** ![StoltzJordan](https://avatars.discourse-cdn.com/v4/letter/s/ce73a5/32.png) [@StoltzJordan](https://forum.inductiveautomation.com/u/StoltzJordan)\
**Post date:** [May 11, 2017, 4:24pm UTC](https://forum.inductiveautomation.com/t/checking-gateway-logs-for-tag-opc-writes/14219/4 "2017-05-11T16:24:56Z")

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Any updates on this? We continue to have some PLC registers dropping to 0 immediately prior to taking on their new values. We’ve worked around it for now, but it would still be helpful to rule out ignition as the culprit!

Thanks!