Black Box 945 - Manual (Page 17)

17
WATLOW Series 945 How to Use Data Communications
ANSI X3.28 "?"
Figure 9 -
ANSI X3.28 "?"
Command Example.
ANSI X3.28 "?" Command Example
You need to know the Alarm 1 Low value (A1LO). The "?" uses a variation of the
message syntax shown just below. This syntax requires the protocol start of
text and end of text characters.
"?" command syntax with ANSI X3.28 Protocol:
<STX> ?<space> <Data.1> <ETX>
Enter in ASCII:
<STX> ? <space> <A1LO> <optional carriage return> <ETX>
The hex string will be:
023F2041314C4F03
First response from the Series 945:
<ACK>
The <ACK> hex response string is:
06
Your computer's confirming response:
<EOT>
The <EOT> response hex string is:
04
Second response from the Series 945:
<STX> <current A1LO value> <carriage return> <ETX>
The hex string is:
023530302003
Your computer's next response:
<ACK> or < NAK> (if the message needs to be repeated).
The hex string is:
06 or 15
Final response from the Series 945:
<EOT>
The hex string is:
04
Response from the Series 945:
<ACK>
The hex response string is:
06
• You'll find the the complete list of "=" command arguments (parameters and
value limits) in Table 6, Pages 20 - 21.
5
0
<STX>
ASCII
Characters
HEX
Value
20
0
0
<
<CR>
<ETX>
ASCII
Characters
HEX
Value
1
41 4C 31
Space
?
3F 20
A
L
<STX>
02 03
Optional
Carriage
Return
O
4F