make the response easier to read. If a crc is not required it is not sent in the
response line. Responses sent by the
I/O
Module are preceded with a start char-
acter symbol, #. All responses are terminated with a CR. Only the number of data
bytes required by the response are sent. Leading zeroes are stripped.
Host S Command:
S or s -
This command queries the
I/O
Module for its communication status.
If the communications line is intact the
I/O
Module responds to the host
with an “OK”.
An example of a valid command to a unit with address M:
> M S crc CR
> M s crc CR
The reply format is:
#OK crc CR
If the command is not recognized, the
I/O
Module responds with “Bad Command”.
An example of an invalid command:
> M x crc CR
The reply format is:
#Bad Command crc CR
If the command is not received no response is sent.
Host T Command:
T or t -
This command tells the
I/O
Module to transmit its current reading. Up
to five ASCII characters are sent by the
I/O
Module. The returned data is in
millivolts if the module is operating in a 0 - 5V mode. If the module is
operating in a 4 - 20mA mode the data is in microamps.
An example of a valid command to a unit with address 5:
> 5 T crc CR
> 5 t crc CR
The reply format is:
#1000 crc CR which corresponds to 1000 mV
or
#19500 crc CR which corresponds to 19500uA
If the command is not recognized “Bad Command” is returned.
An example of an invalid command to a unit with address 5:
> 5 x crc CR
The reply format is:
#Bad Command crc CR
If the command is not received no response is sent. The module returns the ana-
log input data if the command was received and understood.
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