User Manual

Table Of Contents
Setup and Configuration 5-7
SmartPoint Module for the Elster A3 Meter ECMTM40000
5.3.2 Basic Command Message Format
All setup command messages (setup tool to device) with have the following basic format:
CRC is a 16-bit CRC of all of the previous fields, the algorithm used is CCITT-16 (0x1021 or 0x8408
reversed).The remainder is initialized to all 1's (0xFFFF) and the CRC is inverted before being sent,
MSB first. On the following page is a sample C routine which implements the algorithm using the
"reversed" technique:
Byte 0 1 2 3 4->n
n+1,
n+2
Description
Sync Address
Command
Type
Length Data CRC
Value
0x1b 0xff 0x9n
# Bytes in
Data Field