Satec PM172EH series Reference Guide

5
2 ASCII FRAMING
2.1 ASCII Message Frame
The following specifies the ASCII message frame:
Field No. 1 2 3 4 5 6 7
Contents SYNC
(!)
Message
length
Slave
address
Message
type
Message
body
Check sum Trailer
(CRLF)
Length, char 1 3 2 1 0 to 246 1 2
SYNC
Synchronization character: one character '!' (ASCII 33), used for starting synchronization.
Message length
The length of the message including only number of bytes in fields #2, #3, #4 and #5. Contains three characters
between '006' and '252'.
Slave address
Two characters from '00' to '99'. The instrument with address '00' responds to requests with any incoming
address. For RS-422/RS-485 communications (multi-drop mode), this field must NEVER be zero.
Message type
One character representing the type of a host request. A list of the message types is shown in Tables 2-1 and 2-
2. Note that they are case-sensitive.
Message body
Contains the message parameters in ASCII representation. All parameter fields have a fixed format. The data
fields vary in length depending on the data type. Unless otherwise indicated, the parameters should be right
justified and left-padded with zeros. Most parameters are represented in ASCII hexadecimal notation, and in
some cases (to provide compatibility with old instruments) a decimal representation is preserved. For data
formats, see Section 3.2.
Check sum
Arithmetic sum, calculated in a 2-byte word over fields #2, #3, #4 and #5 to produce a one-byte check sum in the
range of 22h to 7Eh (hexadecimal) as follows: [
Σ
(each byte - 22H)] mod 5CH + 22H
Trailer
Two ASCII characters CR (ASCII 13) and LF (ASCII 10).
NOTE
Fields #3 and #4 of the instrument response are always the same as those in the host request.
Table 2-1 Specific ASCII Requests
Message type Description
Char ASCII Hex
0 30h Read basic data registers
1 31h Read basic setup
2 32h Write basic setup
4 34h Reset/clear functions
8 38h Reset the instrument
9 39h Read version number
? 3F Read extended status
@ 40h Read log memory status
B 42h Read analog output allocation
b 62h Write analog output allocation
C 43h Read analog expander channel allocation

Satec PM172EH series Specifications

General

Brand	Satec
Model	PM172EH series
Category	Measuring Instruments
Language	English