Strange behavior with Tag Change Gateway events

Ignition
,
1

Hello everyone,
I have a two step process implemented in Ignition to sync data from one system into another.
In step 1 I poll a REST API every 30 seconds to get the data. Then I compare it with the already existing data in a local Tag Provider. If the value is different I update the value.
Unfortunately there is no other way to get the data and I have to poll it actively.

In Step 2 I have a Gateway Tag Change Script, Which monitors the values from Step 1 and whenever there is a change in value it forwards the data to another system.

Step 1 works fine all the time, but Step 2 fails sometimes. I tested the process for 2 weeks nearly every day and it worked fine. Then i waited for 10 days without any changes in the data and then i tried it again. Step 1 worked fine but step2 does not recognize the change.

My scripts starts with this line and I monitor about 50 items.
if not initialChange and (newValue.getValue() != previousValue.getValue()):

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There are no entries in the log.

Can it be that tags are reset to initial change after a while? Or a monitoring process is disabled?
Has a similar case been reported and is there a solution?

Thanks and BR Gerald

2

  1. An initial change can occur with a new value. There's no previous value and no proper way to know if it is different. Consider just forwarding unconditionally.

  2. Consider just writing unconditionally to the memory tags in step #1. They should filter out non-changes themselves.