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yaacov / node-modbus-serial

A pure JavaScript implemetation of MODBUS-RTU (and TCP) for NodeJS
ISC License
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Help needed with register addresses. #509

Open MIJAS86 opened 1 year ago

MIJAS86 commented 1 year ago

Hi,

I'm quite new to Modbus RTU protocol and I'm bit confused about the register addresses. This is the data I read from Easton SDM72DM power meter with readInputRegisters(1,100) : [ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 50108, 52674, 50059, 1730, 17030, 23989, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 50195, 7819, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 17903, 45703, 17826, 26757, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ] And here is a list of input registers for that power meter: https://xn--stromzhler-v5a.eu/media/pdf/93/17/d7/SDM72DM-V2.pdf image

So my confusion is how the data I read relates to the addresses in the power meter ? If I would like to read one register, let's say 30013 - Phase 1 active power, what parameters I should pass to readInputRegisters?

Thanks in advance for any help!

sigma-design commented 1 year ago

I believe that for your example of reading 1 floating point value (not 1 register !), i.e. read "30013 - Phase 1 active power" the following parameters should be used readInputRegisters(12, 2).

In other words you should use the Modbus 'start' address (last two columns in your table) and required number of registers (keeping in mind that one floating point value occupies 2 Modbus RTU registers).