Data Storage Commands - Stanford Research Systems SR844 User Manual

4-24 Data Storage

Data Storage Commands

SRAT(?){i}
SEND(?){i}
TRIG
TSTR(?){i}
STRT
PAUS
REST
SR844 RF Lock-In Amplifier
The SRAT command sets or queries the Data Sample Rate. The parameter i
selects the sample rate as shown below.
i sample rate
0 62.5 mHz (16 s)
1 125 mHz (8 s)
2 250 mHz (4 s)
3 500 mHz (2 s)
4 1 Hz
5 2 Hz
6 4 Hz
The SEND command sets or queries the End of Scan mode. The parameter i
selects one–shot (0) or loop (1). If loop mode is used, be sure to pause data
storage before reading the data to avoid confusion about which data point is most
recent.
The TRIG command is the software trigger command. This command has the same
effect as a trigger at the rear panel TRIG IN. If the Data Sample Rate is set to
Trigger (SRAT14), then receipt of this command causes data to be sampled and
stored to both the Channel 1 and Channel 2 buffers within 2 ms (actually on the
next 512 Hz clock tick). The command is ignored if the Data Sample Rate is set to
an internal rate, or if the buffers are full, or if the command is received before a
previous TRIG command has completed.
The TSTR command sets or queries the Trigger Scan Mode to On (1) or Off (0).
When Trigger Scan Mode is On (i=1), an external or software trigger starts the
scan. This mode is only applicable for fixed data sample rates set by SRAT
0-13.
The STRT command starts or resumes data storage. STRT is ignored if storage is
already in progress.
The PAUS command pauses data storage. If storage is already paused or reset
then this command is ignored.
The REST command resets the data buffers. The REST command can be sent at
any time – any storage in progress, paused or not, will be reset. This command
will erase the data buffer!
i sample rate
7 8 Hz
8 16 Hz
9 32 Hz
10 64 Hz
11 128 Hz
12 256 Hz
13 512 Hz
14 Trigger