Model 78 and 78-1
Technical Manual
Section 8
Ludlum Measurements, Inc.
Page 8-3
March 2021
the incoming cps. If a variable of 1-199 is entered for TC, the response
time becomes fixed.
Variable Response
- Response time is varied in proportion to the incoming count
rate. The two-position
F
/
S
(Fast/Slow) toggle switch selects the maximum time
constant (TC) for the variable mode. The fast position varies the TC from 4-25
seconds, and the slow position varies from 4-60 seconds.
Fixed Response
- The Fast (
F
) response position is programmable from 2-50
seconds, and the slow response is 5 times slower than the fast TC. For MDA-type
measurements, the fixed response time mode is recommended.
POSITION 7
:
RATEMETER ALARM
/
ALERT
allows changing the ratemeter
alarm for the current detector setup. The units of this alarm are the same as
the units for the ratemeter display. The fifth push of the left button allows
the decimal point to be moved. The ratemeter alarm adjusts from 1µR to
999 R/hr.
POSITION 8
:
NOT USED
POSITION 9
:
NOT USED
POSITION A
:
NOT USED
POSITION B
: LCD Backlight
ON TIME
is the amount of time that the LCD
backlight will stay on after pressing the front-panel switch labeled
BKLITE
. This
value is stored in EEPROM.
Available values are:
5 seconds
30 seconds
60, 90 seconds
180, 240 seconds.
POSITION C
:
NOT USED
POSITION D
:
NOT USED
POSITION E
:
NOT USED
POSITION F
:
NOT USED
