I have a PC and a printer connected to each other through serial port. if i use function codes and Starting Address as defined in the specification is it possible for me to retrieve the data from the printer register using that starting address? As a user how i will know the register address details. Can i send any text instead of address? can anyone please help me in this regard?

 

I understand that your printer is accessible as a Modbus Slave, and you run a Master Modbus Program on your PC. Right ?

Supposing this is correct, you have no way to know the data mapping signifance of this Modbus Slave printer, apart from finding some documentation provided by the printer manufacturer : this documentation explaining which information is accessible at which offset (address), for a given data type (i.e. given Modbus function codes)

Best
Jean-Pierre

 

Each manufacturer of a Modbus-capable device decides what commands it will support, and what information is accessible at each address.

I don't know of any printers that support Modbus as a query/command language. But if there were such, the manufacturer would publish a "register map", indicating what information was stored at what register address, in what format. For writable register, legal values or ranges would also be provided. For an example of such a document, you can visit:

"http://www.joslynhivoltage.com/PDFFiles/INST_FM2500RegisterMapI706-405.PDF":http://www.joslynhivoltage.com/PDFFiles/INST_FM2500RegisterMapI706-405.PDF
"http://www.fireye.com/pdf/epmbus.pdf":http://www.fireye.com/pdf/epmbus.pdf
"http://www.dancon.com/techsup/site_map.htm":http://www.dancon.com/techsup/site_map.htm

Note: I do not necessarily use or endorse any of the above products; I present them only as examples of Modbus register maps published by
device manufacturers. (I do use a variety of devices for which such documents are published.) A google search for "modbus register map" or
"modbus memory map" will turn up a host of others.

Regards,

Greg Goodman
Chiron Consulting