Specifications

SR400 Specifications
6
The STOP key terminates the current count period
and pauses the scan. If scanning, gates and disc
levels are held at their last value. The STOP key
pressed while in a paused condition will reset the
scan and all scanned parameters will return to their
start values. The START key pressed while paused
resumes the scan by starting the next count period.
The DWELL TIME may also be set to
EXTERNAL. In this mode, count periods begin
with the START key or EXTERNAL START
INPUT (TTL rising edge). Count periods
terminate with the preset condition, the STOP key,
or the EXTERNAL STOP INPUT (TTL rising
edge). A STOP key while not counting resets the
scan. This allows completely variable dwell times
and/or counting periods.
All count data is internally buffered for one scan.
Data may be read over the computer interfaces
during or after a scan.
DISPLAY MODE
CONTINUOUS: Displays current counter value
HOLD: Displays final count value
D/A OUTPUT
The front panel D/A Output is proportional to A,
B, A-B, or A+B depending upon the counting
mode selected. The D/A output is updated at the
end of each count period.
There are two rear panel D/A outputs, PORT 1 and
PORT 2. These outputs may be set or scanned
from the front panel or via the computer interface.
Full scale: ± 10 Vdc
Resolution: 12 bits (5 mV)
Current rating: 10 mA
Output Impedance: < 1 Ohm
Accuracy: 0.1% + 5 mV
COMPUTER INTERFACE
IEEE-488 (GPIB) and RS-232 (up to 19.2 kbaud).
Full instrument control and data transmission.
GENERAL
Dimensions: 16" x 13" x 3.5"
Weight: 10 lbs
Power: 35 Watts from 100, 120,
220, or 240 Vac
Warranty: One year parts and labor
on materials and
workmanship