Promax MO-160 Manual De Usuario página 86

The communication protocol is as follows:
1) MO-16X transmits a XON code (0x11) every second. The aim is to indicate to
any possible remote device that the equipment is ready to receive data.
2) At this moment, data streams can be sent to it. Each data stream is made of:
• Initial character '∗' (code 0x2A).
• Set of characters that describe data message.
• Final character CR (carry return, code 0x0D).
3) Once a data stream has been sent, an XOFF will be received, indicating that
the transmission of any new command must wait until completion of the current
one.
4) Next, if the message format is correct and its execution has no errors, an ACK
(acknowledge) should be expected. Otherwise, an NAK (not acknowledge) will
be received.
5) If the sent message requires an answer, it will be sent at this point.
6) Once completed the message processing, the MO-16X will send an XON
indicating that its ready for a new command.
A typical communication timing diagram would be as follows:
PC
⇐
1) XON
2)*?NA<cr> ⇒
⇐
3) XOFF
⇐
4) ACK
5) wait ...
⇐
6) *NAMO-160<cr>
7) wait ...
⇐
8) XON
Commands should always be sent in capital letter and cannot be edited online,
i.e., once a character is received it is stored in the MO-16X buffer and cannot be
rectified by sending an erase code.
When in communication idle mode (MO-16X waiting for a command) the
instrument will send an XON code at one second intervals, to allow synchronisation.
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MO-16X
(equipment ready for command)
(command issued by the controller)
(command received indication)
(command accepted / understood)
(execution delay)
(command answer sent)
(usually some small delay)
(equipment ready for command)
(All characters are transmitted in ASCII code)
USER'S MANUAL. MO-16X
04/2008