9
Chapter One: Remote RS-232 Operation
RS-232 Protocol
Messages sent
to the device
from a remote computer are either:
Commands that instruct the controller to perform a task or change an operating parameter, or
Requests that prompt the controller to report information.
The format of the commands sent to the device appears as:
command value
where:
command
is a label that allows you to identify the command.
value
identifies the task or parameter to be changed.
Requests (R) are numbered chronologically, each with a different function, and appear as:
R #
Messages sent
by the device
to a remote computer are
responses
. The responses are replies to requests sent by
the host computer.
The format of responses sent by the device to the computer appears as:
response value
where:
response
is a label that allows you to identify the response.
value
is the requested information.
Security
To help ensure that certain parameters are not changed inadvertently, some commands require that the
instrument be placed into a Calibration mode. To enter the Calibration mode, the serial command “CAL
1234” is sent to the instrument. To return to the default user mode, send the command “USR”. To determine
which mode you are in, send the request operating mode command “ROM”. This will either return “USR” or
“CAL”. On power up, the mode is set to user.
Throughout the manual, commands which require the instrument to be in Calibration mode are so indicated:
Message Syntax
The RS-232 message syntax uses the following conventions:
Note
1. Commands and requests are
not
case sensitive.
2. Spaces are included in the syntax for clarity only. Do not include spaces in actual
messages.
