Last Updated on 2021-02-02

KB00010: Item states are not synchronized in real-time via MQTT

EVA ICS versions: 3.0.0 and above

Problem

Item states are not synchronized in real-time between controllers via MQTT.

Solution

Step 1

Check MQTT notifier configuration on both sides.

Step 2

Use mosquitto_sub or another MQTT client to make sure MQTT packets are sent correctly:

mosquitto_sub -d -h localhost -u eva -P test -t 'sensor/#'

Step 3

Make sure both nodes have time synchronized. If the target system has the system time set later than the source, the packets from source will be ignored.

Starting from EVA ICS 3.3.2 there is an option for MQTT notifier to send event packets from the source node without timestamps:

eva ns uc set eva_1 timestamp_enabled 0
eva uc server restart

Event timestamps play the very important role in data synchronization and this option should be used only if there is no way to correct time difference between EVA ICS nodes.

tags: cloud, item, realtime, sync

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