Teledyne HASTINGS 2002, Инструкция по эксплуатации, Страница: 28 / 49

page 28
6.3 Operation of the Serial Interface
Communication with the serial interface of the Model 2002 is via an ASCII data string. In the RS-232
mode the command message consist only of a command string and the terminator. The attention
character and address string are not required, but if they are used they MUST be valid. If all compo-
nents of the ASCII data string are valid the command will be accepted and executed. The RS-232
mode is sometimes referred to as point-to-point mode since only one device may be connected to the
controller at any given time.
A message to the Model 2002 in the RS-485 mode consist of an attention character followed by
the address string , the command string, and the terminator. If all components of the ASCII data
string are valid the command will be accepted and executed. The RS-485 mode is also referred to
as multipoint mode since up to 31 devices may be connected to the same controller in a network
scheme.
COMMAND SYNTAX
In the following examples of syntax codes, the special characters are explained:
The characters in square brackets [ ] represents a command string, either upper or lower case
command characters accepted. All characters must follow each other in the string with no spaces or
other characters.
The characters within wavy brackets { } contain choices for the appropriate command.
The characters within the symbols < > are the common abbreviations for the one digit ASCII
control codes which they represent, (e.g. <CR> represents carriage return).
When entering more than one command in the same data string, they must be separated by a
comma.
All command strings must be followed by the terminator character (carriage return <CR>, also
known as ENTER).
When a lower case character is present in an example it represents an option.
Character Description Valid Inputs:
a RS-485 Address (hexadecimal 0-9, A-F) 01 - FF
m Most Significant Digit Of Mantissa 1 - 9
d Decimal Digit 0 - 9
e Exponent 0 - 5
u Unit Of Pressure T, M, or P
, Command Separator (comma) N/A
<CR> Command Terminator (carriage return) N/A