MQTT Transmission - Messages Not Arriving at Broker During Bulk Tag Writes (200-300 Tags)

Ignition Modules MQTT Modules
1

We are experiencing an issue where MQTT messages fail to arrive at the broker when a large number of tags are written in a short timeframe.

Setup:

  • Tags are written using system.tag.writeBlocking([uns_path], [json_string])
  • Each tag is of type Document and receives a JSON payload
  • MQTT Transmission module publishes messages to the broker via Sparkplug B
  • Store and Forward is enabled

Behavior:

  • Under normal conditions (low volume of tag changes), messages are published and received at the broker as expected.
  • When 200–300 tags are written within a ~2-second window, the corresponding messages do not arrive at the MQTT broker.
  • If the same tags are then republished manually (one at a time), the messages arrive without issue.

We would appreciate guidance on identifying the root cause.

2

This definitely shouldn’t be happening. I think we’ll need to see logs. Can you open a support ticket via the form below so we can dig into this?

1 Like