Modbus TCP Scaling

How to scale the value read over Modbus TCP to engineering units? For example, to convert raw 0 to 65,535 to 0-1000 RPM.

Hi,

usually the Modbus devices return the data that is already in the correctly scaled format. For your case, your only option is to use a math channel and scale the data yourself. For the above example, the coefficient between the maximum input and output is 15,259, so I would create a formula that would look like this: 'ModbusChannel'* 15.259, and write the unit as RPM. Therefore, when the input signal would equal 65.535, the math channel would output 1000 RPM.

Thanks for the reply.

It seems like new release of Modbus TCP plugin allow write to coils and registers, but I didn't see anywhere it explicitly says it can write. Could you confirm?

It would be nice to have the scaling option on Modbus TCP plugin, similar to the scaling available on Modbus RTU plugin. Please consider adding this feature in your next release.

Hi,

the Modbus TCP/IP plugin cannot write, it can only read data.

Both of the features that you've mentioned could be implemented, but they require quite a bit of work. Currently, there is no plan to implement either of them. For the scaling request, I'd recommend to stick with the formula approach for now, since it works and isn't hard to configure. You unfortunately won't be able to write data with Modbus TCP/IP in the foreseeable future. If you're extremely interested in the addition of any of these feature, then your only other option is to contact our sales team and ask for a quote for their specific development.

Sorry for asking too many questions on this thread.

Does Modbus RTU plugin write capable?

Thanks fotr your support.

Hi,

sorry for a bit of a delay on the topic. The Modbus RTU plugin can also only read data.