Model 177
Technical Manual
Section 1
Ludlum Measurements, Inc.
Page 1-1
October 2018
Introduction
he Ludlum Model 177 Alarm Ratemeter may be used with GM
(Geiger-Mueller) or scintillation detectors for contamination
monitoring, surveying and area monitoring. The unit provides four
ranges (in decades) of the analog meter, enabling measurement from 0
to 500,000 counts per minute (CPM) on the standard meter dial; others are
available. Detector high voltage is adjustable from 400 to 1500 volts.
The unit incorporates an adjustable alarm set point. The alarm setting may be
checked by depressing the front-panel
TEST
switch. Audible and visual
enunciators are triggered when the meter reading rises above the alarm set
point. Accessory outputs include: Unbuffered Output, Supply Voltage,
Negative Pulse Output, Recorder, and Alarm Sink for Remote Relay. The unit
may be operated from an internal rechargeable battery or by external 9 Vdc
wall transformer.
Section
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