Issue with multiple modbus getter nodes

General
1

Hello guys,

I have an issue with the use of multiple Modbus-Flex-Getter nodes.
I am working with raspberry pi 3b+ and use following software versions:
afbeelding

I have expanded my project to communicate now with 3 solar inverters and 1 energy meter, on basis of modbus-tcp. As I said I use modbus-flex-getter for data collection. For every connection I have configured a separate modbus-server configuration.

My problem is as follows, now that I have increased from 3 to 4 connections, there is always 1 that is not reading data for some reason. Every time I restart node-red. There is only 3 connections reading data, the one not reading data is quit random. I also tried decreasing polling time from 1 sec to 10 sec, but that doesn't seem to be the cause. The connection that's not reading data, cycles through:
->reconnect->initialize->connected->queuing .... and back again.

My question is, is there some sort of limitation on the number of connections you can make, or is there another cause for this problem?

2

There will be a limit (memory/CPU/resources) but 4 connections is pretty low.

Likely something something else. Perhaps you are running parallel reads? Or the connection to the fourth device is noisy? Or something else...

3

@Steve-Mcl I just found the cause.

I have my running project that I only update with changes after rigid testing these changes on a test RPI.

On my test RPI I communicated 4 times with the same energy meter.
Up to three times went well, but 4 times was somehow too much.

So I implemented the energy meter on my running project and there it worked well, so with 3 inverters and now extra 1 energy meter.

So three times seems too be the max number of connection to 1 IP-address with modbus-tcp.

4

This topic was automatically closed 14 days after the last reply. New replies are no longer allowed.