EG&G ORTEC 775 Bedienings- en onderhoudshandleiding - Pagina 7
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Pagina afdrukkenORTEC 775 and 776H COUNTERS
1.
DESCRIPTION
The ORTEC 775 Counter is a general-purpose 6-decade
sealer with an adjustable input discriminator. It accepts and
counts positive
pulses if their amplitudes exceed the
discriminator threshold setting, which has a range of 100
mV through 10 V. The input pulse pair resolution is <50
nsec, and the maximum counting rate is 20 MHz.
The 775 is packaged in a NIM-standard single-width
module. It includes all the connectors and controls for
either manual or automatic operation and indicates the
accumulated count with 7-segment l ight-emitting diodes
(LED's) in a direct-reading digital display.
A Gate LED indicator l ights to show when the 775 is in a
counting condition. The gate is controlled by both the
manual Count/Stop switch and the Gate signal input
circuit, with connectors on both the front and rear panels.
If the counter overflows, this condition is also shown by an
LED on the front panel; the indicator remains lit from the
first overflow until the unit is reset. At each overflow an
output pulse is also furnished through a rear panel
connector and may be used for connection into another
counter for an increased counting capacity.
Reset is generated automatically when power is first applied
and can be provided manually or by a signal through a rear
panel connector at any time, whether the unit is or is not in
a counting condition.
The 7-segment digital display can be tested at any time by
pressing the Test switch on the front panel. When this
switch is pressed, al l seven segments in each digit should
l ight to provide a reading of 888 888.
The 775H operates identically to the 775 but requires that
the bin and power supply in which it is operated furnish +6
V dc as a power source. The ORTEC 401B/402H Bin and
Power Supply is typical of the equipment required.
2. SPECIFICATIONS
2.1. PERFORMANCE
Count Capacity 6 decades, for 000 000 through 999 999.
Counting Rate 20 MHz guaranteed.
Input Discriminator Adjustable through range of +0.1 to
+10 V; drift <0.01% of ful l scale/°C, 0 to +50°C.
Automatic Clear Generated when power is turned on
initial ly or after a power failure.
2.2. INDICATORS
Readout Display 6 direct-reading 7-segment LED digits.
Overflow
LED il luminated from first overflow unti l reset.
Gate LED illuminated while unit is in the counting
condition.
2.3. CONTROLS
Display Test Push-button switch l ights al l 7 segments of
each digit in the display when it is pressed for a reading of
Discriminator Single-turn potentiometer sets the discrimi
nation level for the positive input signal from 100 mV to
10 V.
Reset Push-button switch resets display and internal logic
to an initial condition when pressed.
Count/Stop Toggle switch selects counting or noncounting
condition of the unit manually.
2.4. CONNECTORS
Input Front and rear panel type BNC connectors accept
positive unipolar or bipolar signals to ±25 V maximum.
Input amplitude must exceed adjusted threshold level for