Newby needing help on Addressing MODbusRTU

[icecube]

I am brand new to this world. I just got a Triangle Tube Prestige Solo boiler installed in my house that supports Modbus on RS485. I downloaded what appears to be excellent documentation on the supported commands and registers. I assume that I am supposed to put the register address into the PLCAddressValue field to read the register. I am not sure if I am supposed to use the HEX or Decimal values and I tried both but it isn't working. I am sure that it is a very basic newbie question but I have not been able to find an answer.

An example would be the Boiler Flue Temperature which is an input register (DEC 04/HEX 0x4) with an address of DEC 771/HEX 0x0303. The Byte format is listed as LB:S8. What would I enter into the PLCAddressValue field to pull this data?

Thank you for your patience.

[Archie]

Modbus addressing can be confusing because some documentation refers to function codes and others refer to the address regions. I would recommend going through this thread to help get an understanding:

http://advancedhmi.com/forum/index.php?topic=765.0
 

[bachphi]

check out this link. He's done it with Raspberry Pi

http://sandeen.net/modbus-boiler/

[icecube]

Thank you for the links. watched the youtube video and read the other posts. I also checked out the other RPi implementation of the triangle tube boiler. I feel more confused and less intelligent but I was able to get two of my readings so far. I will tinker with it further over the weekend and then mono it on my RPi.

You folks are awesome.