MQTT Transmission tag limit

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1

Hi Everyone
Im setting up MQTT Transmission client to publish data to an AWS IoT Core Broker and seem to be running into a tag limitation.
Ignition v8.1.33, MQTT Transmission v4.0.18
When I increase past 105x instances of a UDT which has 5x tags and 1x parameter, my server connection continually drops. According to the logs, it establishes a connection and drops it straight away. No tags are visible on the broker. If i reduce the quantity of UDT's it becomes healthy straight away.
I'm assuming there will be some level of overhead for the UDT, but I was able to create 1000 memory tags and connect (vs the 105x5=750 tags from the UDT instances).
Has anyone experienced similar tag count limitations?
I tried the 'Optimize UDTs' selection on the Transmitter settings with no change.
Perhaps I need to increase the options in the 'Filtered Properties' section, although it looks like there is a lot there already.
I saw somewhere on google that SparkPlug B has a limitation of 65535 'tags', but not 100% how that relates to Ignition and its meta data tags (EngUnit, EngHigh, etc)

2

This is more likely due to AWS IoT Core's message size limitation of 128 KB.
When a client publishes a message that exceeds the limit, IoT Core will drop the connection.

https://aws.amazon.com/iot-core/pricing/#:~:text=You%20can%20send%20and%20receive,metered%20in%205%20KB%20increments.

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2 Likes
3

Thanks TChenier, I'd guess thats probably it.
I have updated my Transmitters Sparkplug Settings and seems to be healthy at the moment. I previously used all Group ID, Edge Node ID and Device ID. I have now removed the Device ID. I'm assuming this splits the tags up instead of one large lump of data.
Thanks!

4

I saw somewhere on google that SparkPlug B has a limitation of 65535 'tags', but not 100% how that relates to Ignition and its meta data tags (EngUnit, EngHigh, etc)

I have a transmitter pushing 173566 tags with no problems.