Model 375

Area Monitor Controller

Part Number: 48-2230

Features

• Affordable Digital Controller
• Adapts to a Wide Variety of Detectors
• Programmable Alarms and Units of Measure
• Networkable (Requires Ethernet or Webpage Interface Option)
• Battery Backup

The Model 375 is a digital area monitor controller for radiation measurement or detection. Its simple design accommodates many different detectors, suiting a wide variety of applications, and is equipped with a large digital LED display and alarms. This versatile instrument may also be connected to optional auxiliary indicators/annunciators for alerting personnel at remote locations. The user-friendly, digital design enhances setup and operation. This unit may also be networked to a central PC-based station where data are logged and alarms posted.

This affordable and flexible system can be used in many different applications, and over the years Ludlum Measurements has developed a wide array of detectors, accessories, and options that can be included in a Model 375 system configuration. These include remote indicator alarms, printers, relay outputs, weather-proof enclosures, Ethernet networking software, industrial cameras, and more. See the link in the "Options" tab for more information about the options that are available.

There are several basic versions of the Model 375. In 2011, Ludlums released an updated version of the Model 375, but we still continue to offer the legacy version for some configurations. The specifications listed on this page are for the Model 375 released in 2011.

• Click here to view the break-down of the different versions.
• Click here to view a table of which Model 375 version is included with standard configurations.

Commonly supplied, pre-configured systems employing the Model 375 controller are listed below on the “Configurations” tab.

Several different software options are available depending on the requirements of your application. Details can be found through the link on the "Options" tab.

• Specifications
• Options
• Documents
• Video
• Configurations
• Replacement Parts

• Specifications
• Options
• Documents
• Video
• Configurations
• Replacement Parts

Specifications

Indicated Use	Area monitoring
Compatible Detectors	GM, proportional, scintillation, neutron
Display	Four-digit LED display with 2 cm (0.8 in.) digits
Display Range	000.0 to 9999
Display Units	Can be made to display in μR/hr, mR/hr, R/hr, μSv/h, mSv/h, Sv/h, μrem/hr, mrem/hr, rem/hr, cpm, cps, and others
Linearity	Reading within 10% of true value
Response	Typically 3 seconds from 10% to 90% of final reading
Status Indicators	Status: green light indicates instrument is functioning properly Low Alarm: yellow light and slow beep (1 per second), can be set at any point from 0 to 9999 High Alarm: red light and fast beep (4 per second), can be set at any point from 0 to 9999 Detector Fail: red light and constant audible tone > 68 dB at 61 cm (2 ft), for conditions of detector overload, no count from detector, or instrument failure Low Bat: yellow light, indicates less than two hours of battery life remaining Overload: display reading of "–OL–" and audible FAIL alarm indicate detector saturation Overrange: display reading of "– – – –" and activated low and high alarms indicate that the radiation field being measured has exceeded the counting range of the instrument (or when dead time correction accounts for more than 75% of the displayed reading)
High Voltage	Adjustable from 450 to 2500 V
Threshold	Adjustable from 2 to 100 mV
Dead Time	Adjustable to compensate for dead time of detector and electronics (can be read on display)
Audio	Intensity can vary from approximately 68 to 100 dB through operation of the external rotary baffle and the internal voltage connection. Frequency is approximately 3 kHz.
Data Output	9-pin connector providing 5-decade logarithmic output, RS-232 output, signal ground connection, FAIL and ALARM signals (current sink), and direct connection to battery and ground
Relays	9-pin connector with male pins provides connection to three fail-safe form C relays, activated by LOW ALARM (alert), HIGH ALARM, and instrument FAIL. These contacts are potential-free (non-powered), but can handle 125 Vac at 0.3 A or 30 Vdc at 1 A.
RS-232 Output	A 2-second dump for computer data logging
Calibration Controls	Accessible from front of instrument (protective cover provided)
Power	9 Vdc wall-mount adapter, handles any mains voltage worldwide, supplied with four sets of prongs for almost any style wall receptacle
Battery Life	48 hours in non-alarm condition (typical) 12 hours in alarm condition (typical)
Battery Charger	Battery is continuously trickle-charged when instrument is connected to line power and turned on
Connector	Series "C" (others available)
Construction	Wall-mount aluminum housing with ivory powder coat
Temperature Range	-15 to 50 °C (5 to 122 °F) May be certified for operation from -40 to 65 °C (-40 to 150 °F)
Size (H x W x L)	18.7 x 24.6 x 6.4 cm (7.4 x 9.7 x 2.5 in.)
Weight	2.1 kg (4.7 lb)

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Options

Option	Description	Part Number
Model 375 Series Options	Various options are available for the Model 375 Series including: Enclosures Remote displays Alarm annunciators Signal outputs Software & networking options	Various

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Documents

• Data Sheet
• Product Manual
• Ethernet Manual Addendum (for instruments with ESP32 Ethernet board)
• CE Certificate

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Video

Model 375 Overview

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Configurations

Product	Detector	Range	Application
Model 375/1	Internal 18 mm CsI Scintillator	0.1 - 9999 µR/hr	Area Monitoring
Model 375/2	Internal Energy Compensated GM	1.0 µSv/h - 10 mSv/h (0.1 mR/hr - 1.0 R/hr)	Area Monitoring
Model 375/4	Internal Energy Compensated GM	10 µSv/h - 100 mSv/h (1.0 mR/hr - 10 R/hr)	Area Monitoring
Model 375-9	External Model 45-9 Ion Chamber	Any 4 Consecutive Decades Between 0.1 mR/hr - 100 R/hr	Area Monitoring
Model 375-10	Internal NaI(Tl) Scintillator 5.1 x 5.1 cm (2.0 x 2.0 in.)	0.1 - 20 µSv/h (1 - 2000 µR/hr)	Area Monitoring
Model 375-20	Two External NaI Scintillators 5.1 x 5.1 cm (2.0 x 2.0 in.)		Waste Monitoring Indoor/Outdoor
Model 375-30	Two External NaI Scintillators 7.6 x 2.5 cm (3.0 x 1.0 in.)		Waste Monitoring Indoor/Outdoor
Model 375-31H	External Neutron Detector 2 atm 3He tube with 22.9 cm (9 in.) dia. Moderator	0 - 100 mSv/h (0 - 10 rem/hr)	Neutron Area Monitoring
Model 375-600	Internal Plastic Scintillator 10.3 L (630 in3)		Scrap Monitoring
Model 375P-336 Series	Two External Plastic Scintillators 2753 cm3 (168 in3) Each	0 - 9999 kcps	Waste Monitoring Indoor or Indoor/Outdoor
Model 375P-1000	Two External Plastic Scintillators 7866 cm3 (480 in3) Each	0 - 9999 kcps	Scrap Monitoring, Waste Monitoring Outdoor
Model 375P-3500	External Plastic Scintillator 57.4 L (3500 in3)	0.1 - 9999 kcps	Scrap Monitoring Outdoor

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Replacement Parts

Description	Part Number
Rechargeable Batteries	21-9705

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