Implementing Node Red on Raspberry Pi 4 Model B, 2GB RAM, using latest, generic Raspberry Pi OS. Nothing special. RPi connected via ethernet to air-gapped network with ~15 total IP devices. Using Modbus TCP/IP I am integrating to a device with several registers in the 4x,xxx category. The registe…

[image] Stomachbuzz: When polling anything beyond that, it gives an error Have you tried a different Modbus master software like QModMaster to see if you get any errors ? Did a quick test with a Modbus simulator ( pyModSlave ) and the Modbus-Read node works ok for me with those high register…

I have not tried any other software. I'm not familiar with QModMaster, although I may try it. I am using this RPi to create a simple dashboard for values polled over Modbus.

Through lots of tinkering, I discovered the solution. For the specific register(s) I was trying to poll, they are 32-bit registers, split into 2 16-bits, with upper register first (sequentially lower) and lower register second. For example, upper register: 42097; lower register 42098. For this sp…

Im glad you found the solution to the problem :+1: now that you mention it i read a couple of times on the forum that some devices start their register numbering with an offset of 1 ( example ) does that mean you need to make corrections to all reads you were making ? even the lower number register…

Ah I spoke too soon. I had gone into the Modbus-serial module folder and modified the index.js file to comment out the error checks. When I got it working, I thought I figured out the issue, so I went back and put everything the way it was. Then the issue returned. I checked each individually and …

Further question, now that I'm in the heat of implementing this Raspberry Pi solution, what do you think the best method would be? Polling modbus devices, incorporated in a Building Automation System, to show certain values on a large TV/display. Using RPi with Node-Red to poll devices and dashboar…

Hi .. are those 8 TVs going to be in the same building ? if yes then you may not even need another 7 RPis .. just the one being modbus master with Node-red and Dashboard and the TVs can be smart TVs on the same network with their Browsers open pointing to that single Pi's Dashboard.

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Node-red-contrib-modbus - Errors when polling numerically high registers

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Stomachbuzz 9 February 2023 20:40 3

Error: Data length error, expected 7 got 6

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Node-red-contrib-modbus - Errors when polling numerically high registers

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