ROTRONIC MBW 973 - Manual (Page 34)

30 Communications Settings
Communications Settings
To communicate with the 973, set your computer to the following settings.
Baud Rate:
9600
Data Bits: 8
Stop Bits: 1
Handshaking: None
Command Syntax
This section details the general syntax guidelines regarding termination, leading and trailing
spaces, case sensitivity, and numeric values. Throughout this section, characters originating
from the computer will be shown for illustrative purposes in this font. Characters
originating from the 973 will be shown in this font.
General Usage
All commands require either a question mark or an equal sign to indicate whether you are
requesting data or setting new setpoints or parameters. When requesting data from the 973,
follow the command with ?, the question mark character. For example, the following requests
the current Automatic Mirror Check timing interval..
AMC.cycleTime?
The 973 replies with the current AMC cycle time. This value may have been entered from the
touch screen or as you will now see, via RS-232.
When setting new values or parameters, use =, the equal sign. For example, the following
command changes the Automatic Mirror Check timing interval to 20 minutes.
AMC.cycleTime=20
Most commands that can be set with an equal sign, such as the one in the above example,
may also be read with the question mark. That makes sense. However, there are several
commands that are considered read only, and have no corresponding ability to be set.
Examples of read only capability are measured parameters, such as dew point, frost point,
RH, etc.. While it is perfectly valid to read dew point with a command such as dp?, it
obviously makes no sense to be able to set the dew point value. Therefore, a command such
as dp=1.23 is considered invalid, and will be ignored by the 973.
Termination Characters
All commands must be terminated with either a carriage return C
R
or a carriage return linefeed
combination C
R
L
F
.
Regardless of the command sent, the 973 will reply with a carriage return linefeed
C
R
L
F
at the
end of the response, provided the command is recognized as valid. Here is an example:
DP? C
R
(sent by the computer to the 973)
-10.015 C
R
L
F
(sent by the 973 back to the computer)