Non Function Key Operations; Serial Port Command And Control; Data Requests - AEA VIA Bravo MRI Operating Manual

9.2.2 Non Function Key Operations

First Action Final Action
Freq up
Numeric entry
Freq down
Width up or
Freq up
Freq down
Width up
Width down
Exam/Plot Freq up or down

9.3 Serial Port Command and Control

The VIA Bravo MRI serial port sends and receives strings of ASCII
characters. These strings usually contain several pieces of information.
Each piece of information has a letter prefix to identify the information that
immediately follows. This information is usually a number in ASCII format.
Decimal points are not sent, the decimal position is inferred by the prefix
letter. The end of a piece of information (such as a number) is denoted by the
prefix letter of the next piece of information. At the end of the command (or
response) string, an End Of String (EOS) marker is appended. This EOS
marker pushes the last piece of information through the software routines.
Some commands do not require the EOS marker. The VIA Bravo MRI unit
sends an EOS marker in response to a command. If the VIA Bravo MRI
doesn't understand the command, no EOS response occurs. The ASCII char
'*' (ASCII 0x2a) is used as the EOS marker. The VIA Bravo MRI unit
appends the EOS character to the end of any response.
The commands to the VIA Bravo MRI unit fall into two major categories;
1. Data request
2. Unit setup
These commands and the unit's responses can be controlled or read via
the VIA Director software or by any terminal program running on a PC. The
controller unit that communicates with the VIA Bravo MRI unit will be referred
to as the Terminal throughout this document.

9.3.1 Data Requests

The data requests are short commands that receive a fairly large block of
data from the unit. This data can be one of several formats, as selected in
the unit setup. These formats are:
Impedance magnitude and angle.
Resistance and reactance
Enter
New step size and center frequency incremented
New step size and center frequency decremented
down
Center frequency incremented by step size
-
Center frequency decremented by step size
-
-
-
Move cursor across plot and view plot values at
Result
New center frequency
New sweep width
Sweep width doubled
Sweep width halved
the cursor frequency
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