Environment: Ignition 8.3.7, MQTT Transmission 5.0.4, Sparkplug B to a third-party MQTT broker. OPC UA source is a third-party server; Ignition is the OPC UA client (subscription based).
Problem: When an OPC UA node becomes unavailable (source-server update, or the tag is deleted upstream), Ignition reports Bad_NodeIdUnknown and refreshes the tag’s timestamp every ~10 s. This is probably wanted behavior for a failed item retry loop, i have not found the setting which controls this.
My challenge is that the MQTT transmission module sees the timestamp update of the tag and publishes a data point with a Null value each 10 seconds. see: Suppress DDATA publishing for tags in "Error" state without disabling them — MQTT Transmission 5.0.4 - Ignition Modules / MQTT Modules - Cirrus Link Forum
reproduction: Take a working subscribed OPC tag and change its Item Path to a non-existing node (simulating a deletion). Observe DDATAs has null values for the tag every 10 second.
Question: Any good recommendations on how to handle this? Is there a way to prevent the change events from occurring when in this state? or at least increasing the failed item retry loop time.
This error tag is of course always a transient problem, but manual intervention takes time.