How to transform a modbus value to a Datastore value

I use modbus for reading some data. The problem is that I would like to transform this data into datastore data to then be able to read it on nodered. Proceeding like this is simpler for me because I have difficulties in obtaining the data directly with the nodes that nodered offers. Is there a way to do this?


Welcome to the forums Glory.

Its a somewhat common request… being able to export groov View device tags to other devices or an API in groov View.
At the moment that’s not possible.

So, back to Node-RED. A LOT of people use the nodes to talk with their modbus devices as once you have it in Node-RED you can move the data into PAC Control and groov View.
Also the Node-RED modbus nodes seem to be easier to use than the PAC Control modbus toolkit.

I think at this point, given your post, I suggest reviewing some of the Node-RED modbus forum posts and you should be up and running in short order.

TIP, the forums search works really well, but do feel free to post questions with some screenshots and examples of what you are seeing in Node-RED.

1 Like

Thank you for your quick reply @Beno. As you have suggested I’ll review the Node-RED modbus forum posts and try again.

Hello @Beno, here is the challenge I’m facing
I just want to read a single value at a specific address but I can’t do it. It only works when the quantity value is even. But I can easily do this with groov view. In addition with groov view I can directly display the float value and I would like to be able to do the same thing with nodered. Thanks for your help !

Just as you had to try a few different settings getting the Modbus value to show up in groov View, you are going to have to try a few different settings in Node-RED.
Modbus is a very poorly implemented ‘standard’, so trial and error is the best way to get it working.

You have not mentioned what device you are using, or provided a link to its Modbus command manual, so you will need to test things out making notes along the way so you ensure you test all possible combinations.

This is a great Modbus troubleshooting thread here, you will also find lots of Modbus tips in by using the search in the forums…

I think groov uses 1-based addressing by default. The modbus Node-red nodes use 0-based addressing - so use address 64 in Node-red. If you are reading 32 bit values, you will need to combine these yourself in Node-red as well. I have examples of this on the forum if you search for it.

1 Like

Hi Ben, is it possible to use the CSERI-4 modules within Node-RED? or do you have to do this via PAC Control? I have a love hate relationship with PAC control and it’s giving me some frustrations while trying to read the CSERI-4 module.

Yes they can.
BTW, the forums search function works really well (and is sometimes faster than me)…
The first result is the one you are after…