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3.9.4
RS-422/RS-485 Protocol
When no Network protocol is selected (SYST:COMM:SER:NET OFF),
the RS-422 interface operates like the RS-232 interface does with echo off.
See the examples in paragraphs 3.9.2 and 3.9.3.
3.9.5
Addressed Network Protocol
The 2307/2367 supports a multi-device or multidrop network connections
when the NETwork Address mode is selected. When Address is selected,
the 2307/2367 recognizes commands addressed to it by checking the first
two characters of the message for the correct address sequence. The first
character must be the STX character. The second character must be the
address character (0-9 and :;<=>?). All responses are the same as for normal
RS-422 and RS-485 operation. If RS485 is On, the transmitter stays
enabled from the response message until the prompt message is sent. The
Address command message format is
STX Addr Message LF
e.g. The IDN query example becomes:
STX 4 *IDN? LF
ICS Electronics, 2307, S/N 910123, Rev. X1.X0 LF
> LF
3.9.6
Packet Protocol
Network messages can be made more secure by enclosing the commands
in a packet that is protected with a checksum. When Packet Protocol is
selected, the 2307/2367 recognizes commands addressed to it by checking
the first two characters of the packet message for the correct address
sequence as described in 3.9.5. The Packet is then checksumed and the
result compared against the checksum at the end of the packet. If the
checksum matches, the command is parsed and executed (assuming it is a
valid command). If the checksum does not match, a NAK response packet
is sent to the controller.
