qitech-control/docs/developer-docs/Xtrem_protocol.md

XTREM Communication Protocol

Version: 3.007 Device: XTREM / XTREM-S Weighing Module Standard: OIML R76:2006 / EN45501:2015 compliant

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Overview

The XTREM communication protocol allows a terminal or host controller to exchange data and commands with the XTREM weighing module. The device transmits and receives ASCII-coded frames over a serial interface (RS232, RS485, Wi-Fi, or Ethernet, depending on configuration).

Since we are using the Ethernet interface we need to provide some kind of DHCP to assign an IP - Address to each XTREM Device. They then may be addressed via a broadcast IP (e.g.: 192.168.4.255/24). A Unicast communication is applied through the device ID inside the XTREM Frame.

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Frame Structure

Each message—both query and response—has the same format:

STX ID_O ID_D F D_ADDRESS D_L DATA LRC ETX

Field	Description	Length (bytes)
STX	Start of message (ASCII 02h)	1
ID_O	Sender address (2 ASCII hex chars)	2
ID_D	Destination address (2 ASCII hex chars)	2
F	Function code (R, W, E, etc.)	1
D_ADDRESS	Data address (register, 4 ASCII hex chars)	4
D_L	Data length (2 ASCII hex chars)	2
DATA	Optional data field	Variable
LRC	Longitudinal Redundancy Check (2 ASCII hex chars)	2
ETX	End of message (ASCII 03h)	1

In the default configuration the Frame also requires a CRLF at the end.

Example:

STX ‘1’ ‘7’ ‘0’ ‘1’ ‘R’ ‘0’ ‘1’ ‘0’ ‘1’ ‘0’ ‘0’ LRC ETX CR LF

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Function Codes

Function	ASCII	Hex	Description
R	R	52h	R