Measurement Computing DAC488 v.1 - Manual (Page 78)

72 DAC488 Commands DAC488 User’s Manual
L - Buffer Location
TYPE Port Command
SYNTAX Lval Sets the location pointer to location val , where val is a value between 0 and
8191.
L? Returns current buffer location. The L? command may be used even when the
DAC488 is running in Stepped or Waveform Control mode.
DESCRIPTION
The Buffer Location command is used to set the location pointer to a specified location in the internal buffer. This
command is used in conjunction with the Buffer Data (Brng,volts) command. After a data value is put in the buffer by
using the Buffer Data command, the location pointer is automatically incremented.
The location pointer points to the first voltage value which will be output when the Stepped (C2) or Waveform (C3)
Control modes are used. Once a DAC port is triggered in the Stepped or Waveform Control modes, the location
pointer will always point to the next location containing the voltage value to be output. Each port has its own location
pointer, therefore the location pointer may be set to a different location for each port. Before triggering a DAC port,
the location pointer should be set to the desired starting point in the internal buffer.
CAUTION CAUTION CAUTION CAUTION
DO NOT USE the Buffer Location ( Lval ) command to change the location pointer
while the DAC488 is generating a waveform in Waveform Control mode ( C3 ).
Otherwise unpredictable operation may occur.
EXAMPLE
PRINT#1,"CLEAR09" Line 1: Reset the DAC488.
PRINT#1,"OUTPUT09;C3 P1 L0
F200,400 G1 N30 I2000 X"
Line 2: Select Waveform Control mode, select port 1, define a buffer
with the first location=200 and the size=400, enable port 1 to trigger
on GET, set the number of cycles to 30, set location pointer back to
0 (first location), set time interval between points to 2 seconds.
Note: Assume that we are using a buffer that has already been
loaded with voltage values. Using the Buffer Definition
(Fstart,size) command above defines what segment of the buffer
we will be using when in Waveform mode.
PRINT#1,"OUTPUT09;L200X" Line 3: Set location pointer to 200 (start of the buffer which was
previously defined).
PRINT#1,"TRIGGER" Line 4: Trigger the DAC488. The DAC488 will output the values in
the buffer starting at location 200. (The buffer we have defined
starts at location 200 and ends at location 600.)