I connect to DELCOS PRO V3 via RS485 Modbus RTU. I don't know address of register to read or write. I read holding register with try , but i can't write on device. Could you please help me to find address of register to command on compressor?
no , i don't install smart air master. I use modbus poll softwareDo you have smart air master installed?
OEM manual showing Modbsu RTU communication protocol with Smart air master...
HiThe device vendor supplies the information as to what data resides in which Modbus register (usually described as a 'map'), and usually describes what the format the data is.
There is absolutely NO general, industry-wide assignment of data to Modbus registers, the assignment of data to registers it is always the decision and implementation of the device vendor.
The device vendor has to supply that Modbus register information.
Sometimes when that is public, a forum participant will provide a link to the public documentation.
The loose affiliation of the this site with Modbus.org does not mean that this forum has access to device vendor data, whether public or proprietary.
The Modbus Function code for writing data to a holding register (that is writeable, as determined by the vendor) is 06 or 16 (decimal), as opposed to the Modbus Function code 03 for reading one or more Holding Registers.