Stanford Research Systems SR865A, Operation Manual

Page: 137 / 221

Chapter 4 Programming 119
SR865A DSP Lock-in Amplifier
CDSP? 1
Returns the parameter index assigned to data channel 2 (blue)
CDSP? DAT2
CGRF(?) [ DAT1 | DAT2 | DAT3 | DAT4 | j ] { , OFF | ON | i }
The CGRF j, i command turns the strip chart graph of data channel j off (i=0) or on (i=1).
The value of j (0
–
3) corresponds to the
DAT1
(green),
DAT2
(blue),
DAT3
(yellow) and
DAT4
(orange) data channels.
Example
CGRF DAT2, ON Turn graphing on for data channel 2 (blue)
CGRF 1, 1
CGRF 0, OFF Turn graphing off for data channel 1 (green)
CGRF? 1
Returns data channel 2 (blue) graphing state i
CGRF? DAT2
GETSCREEN?
The GETSCREEN? query creates and returns a screen image as a binary block of data in
BMP file format. This query cannot be executed over the RS-232 interface. The file
image is the same as is written to a USB memory stick upon pressing the [Screen Shot]
key.
After sending GETSCREEN? , the user’s remote program should repeatedly perform a
Status Byte query, either by serial poll, or through the VISA Read STB function
—
but not
with the STB? query
—
until the MAV bit becomes set. Note that it may take several
seconds before MAV is set. Once the MAV bit is set in the Status Byte, the user may then
read the binary block data. The binary block is in the following format:
#ncccccxxxxxxx
Where “
#
” is the hash character (character code 35), “
n
” is a single digit specifying the
number of digits to follow in the block length count;
“ ccccc ” i
s the
n –
digit integer size
of the binary block to follow, and “
xxxxxxx
” i s the
ccccc
– byte binary image file itself.
This binary image should be saved as a
.BMP
format file.
Example
GETSCREEN? Request a screen capture file
The SR865A responds with
#535219xxxxxxx
corresponding to a 35219-
byte .BMP file image (the “
xxxxxxx
” data).