Danfysik 9700 - Programming

System 9700 User Manual
Page 37 of 56
3.3.4. Programming
The power supply communication protocol is based upon plain ASCII characters where each
command or reply is delimited by a "Carriage Return" <CR> character. Replies however have a
“Line Feed” <LF> character added before the <CR> for a friendlier display when using a
terminal. <LF> characters on commands will be ignored.
HINT
The protocol allows full control of the power supply from a "dumb" terminal. In case of a
service- debug- situation, a terminal can be used to tap the communication transfer by a
simple parallel connection.
HINT
When debugging, the "ERRT" command enables error message to be given as a readable
text.
More commands may be transmitted in a chain, but each single command must be trailed
individually with the delimiter character <CR>. The power supply is able to execute up to 200
commands a second depending upon the complexity of each command.
NOTE
Issuing short commands faster than the time to transmit the answer, e.g. “S1" will
overload the internal transmit buffer regardless of the selected baud rate.
All commands can be divided into two sections:
a) Directive commands. E.g., the "N" command that turns the power supply ON.
b) Status commands. E.g., the "S1" that returns the power supply status.
Status commands always deliver a reply, whereas directive- and setup- commands only respond
with an error message if the command could not be understood or if the given parameters are
incorrect. It is possible to set the power supply to always generate an answer; this feature is
very useful when using RS485 protocol.
HINT
When using the "Always Answer" mode, a re-transmission of the last given command can
be performed if no answer or an error message is received. The MPS 9700 response time is
around 5ms after receiving the last bit of the termination character.
Answer scheme if set to “Always Answer” mode:
c) Directive commands answer:
- No answer
- ERROR message
- OK if set to always answer mode (from SW ver. SCS110)
d) Status commands answer:
- Data
- ERROR message
e) Set up commands answer:
- No answer
- ERROR message
- OK if set to always answer mode (from SW ver. SCS110)
Below is an example written in BASIC on how to turn ON the power supply and read the status
with and without acceptance answer: