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What's the easiest way to interchange a datatable with several PLC's


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I have several PLC's running to control a building (because I can only use 8 URB adapters on 1 PLC ๐Ÿ˜’๐Ÿ˜’๐Ÿ˜’)

On 1 PLC, I communicate with my lighting system (HELVARNET - DALI) to ask the status of my lights.

Because it's a huge building,ย  it takes a while for scanning all lightsgroups.

For every group, I have the status in a data table. But now I want to make this data table is also available for my other PLC's (so they don't have to ask my lighting system what's the state of the lights)

I've tried to update the status with MQTT, publishing and subscribing all status of all lightgroups, but this is to slowly for me.....

What's the easiest way to "send" my data table to the different PLC's ? any suggestions ?

my data table is built with a structure of+- 15 elements (integers, bit arrays, string,...) -> size is 13200 bytes

I need something that can be run in the background, because my scantime is already high.... -> +-50000 ยตs (so I could have problems with my 100ms timer....)


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Since you want to share datatables between different PLCs, the easiest (easy in terms of a few lines of code) way I see, is to write DT from the source PLC to a SQL database, then any other PLC can retrieve data in any time asyncronously. For reference, my PLC program toom about 330 scan cycles to INSERT 50 rows.ย 

If you want to go faster, you would use Ethernet/IP, sending the entire data table (row by row) to each destination PLC.


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