Ametek Thermox Series 2000 WDG-IV User Manual page 157

A-2 | Thermox Series 2000 WDG-IV /I VC / IVCM
Command Message Format
The command message format is as follows:
Where:
The Start Character is the greater than character (">", which is ASCII 3E
hex).
The Node Address is from 00-FF, and is represented as two hex ASCII char-
acters. Each sensor has a unique node address. Note, however, that the
maximum number of sensors that can be connected on the network is 32
and for the gateway, we have limited the valid addresses from 01-32.
The Command Letter is from ASCII A-Z (upper case only).
Data is a string of characters whose meaning depends on the command
(see below) and where the number of characters returned also depends
on the command. Limit is 20 characters.
The Checksum is the sum of all the preceding characters (excluding the >
character) - modulo 256 or the characters "??" (?? is equivalent to 2 ASCII
3F hex characters).
The End Character is a carriage return (equivalent to ASCII character 0D
hex).
The system disables any checking of the checksum if the checksum

character is equal to ?? (?? is equivalent to 2 ASCII 3FH hex charac-
ters). This makes testing by the programmer easy, but it is strongly
NOTE
recommended that the integrity check be enabled in the final system.