Specifications

Remote Programming – Command List
42
99.92E-3. The resolution is variable depending
upon the 4 most significant digits of t.
4 most significant digits
resolution in 4th digit
1000 to 2048 1 (1001,1002,1003,...)
2048 to 4096 2
4096 to 8192 4
8192 to 9992 8 (8192,8200,8208,...)
For example, near 10.00 µs, the allowed values of
t are 9.984 µs, 9.992 µs, 10.00 µs, 10.01 µs, etc.
Below 1.000 µs, the resolution is 1 ns. Almost
any value of t may be sent and the SR400 will
round to the nearest allowed value. If t is absent,
the selected gate scan step is returned. The scan
step may be set and read even if the selected gate
is not in the SCAN mode. Changing the scan step
during a scan will affect the gate position for the
next count period and all those that follow.
GD i { ,t }
The GD command sets and reads the gate delays.
i=0 or 1 designates A gate or B gate and is
required. If t is included, the selected gate delay is
set to t seconds where 0 <= t <= 999.2E-3. The
resolution is variable depending upon the 4 most
significant digits of t.
4 most significant digits
resolution in 4th digit
1000 to 2048 1 (1001,1002,1003,...)
2048 to 4096 2
4096 to 8192 4
8192 to 9992 8 (8192,8200,8208,...)
For example, near 10.00 µs, the allowed values of
t are 9.984 µs, 9.992 µs, 10.00 µs, 10.01 µs, etc.
Below 1.000 µs, the resolution is 1 ns. Almost any
value of t may be sent and the SR400 will round to
the nearest allowed value. If t is absent, the
selected gate delay is returned. The gate delay may
be set and read regardless of the gate mode. If the
mode is CW, the gate remains continuous. If the
mode is SCAN, the GD command sets and reads
the starting position of the gate delay. Changing
the delay during a scan will cause the delay to be
set to the new value on the next count period. Note
that the scan is not reset. Reading the delay during
a scan always returns the starting delay, not the
current delay.
GZ i
The GZ command returns the gate delay position
during a scan. i = 0 or 1 designates A gate or B
gate and is required. If gate i is in the SCAN
mode, its current delay position during a scan is
read. If the counters are in reset or the gate is not
in the SCAN mode, the GZ command returns the
starting delay position (same as GD command).
The GZ command is a read only command.
GW i { ,t }
The GW command sets and reads the gate widths.
i = 0 or 1 designates A gate or B gate and is
required. If t is included, the selected gate width is
set to t seconds where 0.005E-6 <= t <= 999.2E-3.
The resolution is variable depending upon the 4
most significant digits of t.
4 most significant digits
resolution in 4th digit
1000 to 2048 1 (1001,1002,1003,...)
2048 to 4096 2
4096 to 8192 4
8192 to 9992 8 (8192,8200,8208,...)
For example, near 10.00 µs, the allowed values of
t are 9.984 µs, 9.992 µs, 10.00 µs, 10.01 µs, etc.
Below 1.000 µs, the resolution is 1 ns. Almost any
value of t may be sent and the SR400 will round to
the nearest allowed value. If t is absent, the
selected gate width is returned. The gate width
may be read and set regardless of the gate mode. If
the mode is CW, the gate remains continuous. If
the mode is FIXED or SCAN, the gate width is
adjusted immediately.
NOTE
Changing the gate delay or width may cause some
gates to be missed or shortened. Changing gate
parameters while counting may therefore cause
bad data to be collected. It is recommended that
the counters be paused before changing gate
values and then started again.
FRONT PANEL
CS
Sending the CS command has the same effect as
pressing the START key. The CS command may
be sent at any time but only has an effect if the
counters are paused or in reset. If the DWELL