Fluke Biomedical 875 Victoreen - Manual (Page 25)

Victoreen 875 High Range Containment Monitor
Operator Manual
4-4
14 is a voltage regulator with diode U402
p
R
T
m
U
lifier stage can be adjusted by
puter drivers
acts
7) also
y driver stage U503, whose main function is to drive relay K502.
s
inal 3 of the printed circuit board, which is
c to the colle in 7) of U503 sistor R5
A
T m circuit enters a differen mplifier,
w ther input (pin rmined by ote 509. The se of this
s to control the hreshol ut of the on OP AM d, through
d 3, which acts m wer rt (yellow) panel light. The
o o serves a the ale y driver 03, whose
main functio 1. The i rt ala stage on pin 2,
and the output to the relay is taken from p 01 is he non e, and a
s bove threshold de-energ
PreamplifierIMeter Board Power Supply (P/N 876-1-86, Schematic 876-1-3E)
A +6.2 V power supply contained on the preamplifier meter board has as its input the +15 V from the
power supply board. Integrated circuit U401, pins 12, 13, and
roviding a stable reference voltage. The output is adjustable by R413.
elay Driver Printed Circuit Board (P/N 876A-1-75A, Schematic 876A-1-3B)
he signal input to the relay driver printed circuit board which is taken from pin 13 of the preamplifier
eter may be monitored at this point through test point TP501. The signal enters pin 13 of OP AMP
501, and the output is taken from pin 14. The gain of this amp
potentiometer R503. The output of the OP AMP can be monitored at TP502; it provides inputs to:
• High Alarm circuit
• Alert Alarm circuit
• Meter buffer amplifier circuit
• Recorder/Com
High Alarm Circuit
The signal output to the high alarm circuit enter OP AMP U502 on pin 5. This is a difference amplifier,
whose other input (pin 6) is determined by the setting of potentiometer R513. The main purpose of this
stage is to control the high alarm threshold.
The output of the comparison OP AMP is connected, through diode CR504, to pin 6 of U503, which
mainly as a power stage for the HIGH ALARM (red) panel light. The output of this stage (pin
serves as the input to the high alarm rela
The input to the high alarm relay driver stage of U503 is on pin 9, and the output is taken from pin 8.
Relay K502 is energized in the non-alarm state, and a signal above threshold serves to de-energize it.
There is a red HIGH ALARM jumper connected to the collector (pin 8) of the relay driver U503. The
following options are available with the presence or absence of the jumper when the radiation level
exceeds the threshold and triggers the alarm:
Manual Reset - The alarm will continue to be activated even after the radiation level recedes below
threshold until the SAFE/RESET indicator push button on the panel is depressed. This option occur
with the jumper in place.
Automatic Reset - The alarm will continue to be activated only as long as the radiation exceeds the
threshold level. This option occurs with the jumper removed.
The red warning light acts similarly to the alarms. It lights when the alarm relay is de-energized.
Each relay contains four Form C contacts, but only two of the four are accessible through the rear
connector.
The connection to the red panel warning light is from term
onnected ctor (p through re 21.
lert Alarm Circuit
he signal input to the alert alar
2) is dete
OP AMP U502 o
the setting of p
n pin 3. This is
ntiometer R
ce a
main purpo hose o
tage is alert alarm t d. The outp comparis P is connecte
iode CR501, to pin 13 of U50
n 14) als
ainly as a po
s the input to
stage for the Ale
rt alarm rela utput of this stage (pi
n is to driv
stage U5
e relay K50 nput to the ale
K5
rm relay driver
t
of U503 is
t in 1. Relay
ize it.
energized in -alarm sta
ignal a serves to