Ludlum Measurements 375-9 User manual

LUDLUM MODEL 375-9
DIGITAL WALL-MOUNT AREA MONITOR
WITH MODELS 45-9 & 45-9-1 ION CHAMBERS
July 2016
Serial Number 230666 and Succeeding
Serial Numbers

LUDLUM MODEL 375-9
DIGITAL WALL-MOUNT AREA MONITOR
WITH MODELS 45-9 & 45-9-1 ION CHAMBERS
July 2016
Serial Number 230666 and Succeeding
Serial Numbers

Ludlum Measurements, Inc. July 2016
Table of Contents
Introduction 1
Getting Started 2
Unpacking and Repacking 2-1
Connecting the Detector 2-2
Power Up 2-2
Radiation Units 2-3
Checking Parameters 2-3
Setting Alarm-points 2-4
Operational Check (optional) 2-4
Specifications 3
Instrument Specifications 3-1
Detector Specifications 3-2
Operator Controls and Setup 4
Calibration Controls 4-1
Dipswitch (under calibration cover) 4-1
RS-232 Output 4-2
Demonstration Program 4-3
9-Pin Data Connector 4-4
Common Options and Modifications 5
Time and Date Stamp Option 5-1
Relay Options 5-2
4 to 20 mA Isolated Output Driver Option 5-3
Safety Considerations 6
Environmental Conditions for Normal Use 6-1
Cleaning Instructions and Precautions 6-2
Warning Markings and Symbols 6-2
Replacement of Main Fuse 6-3
Battery Replacement 6-3

Model375-9 TechnicalManual
Ludlum Measurements, Inc. July 2016
Calibration 7
Instrument Calibration Parameters 7-1
Analog Output 7-1
Threshold 7-2
Battery Charge 7-2
Detector Calibration 7-2
Detector Electronics Checkout 7-3
Recycling 8
Parts List 9
Model 375-9 Digital Wall-Mount Area Monitor 9-1
Main Board, Drawing 396 × 608 9-1
Wiring Diagram, Drawing 396 × 869 9-4
Model 45-9 Remote Area Monitor 9-4
Model 45-9-1 Remote Area Monitor 9-4
Remote Electrometer, Drawing 280 × 219 9-4
Drawings and Diagrams 10

Model375-9 TechnicalManual Section1
Ludlum Measurements, Inc. Page 1-1 July 2016
Introduction
he Model 375-9 Digital Wall-Mount Area Monitor is designed for
visibility and ease of use. Featuring a wall-mount chassis, the Model
375-9 has a four-digit LED display that is readable from thirty feet
away. Backlit indicators warn of low radiation alarm (yellow), high
radiation alarm (red), instrument failure (red) and low battery (yellow). A green
status light is a positive indication of instrument operation.
Note:
The Model 375-9 Ethernet (1370-055) option:
The Model 375-9 can also be modified to add a 100BaseT
Ethernet port. This port allows remote display and logging of
the data from the Model 375-9. To do this, special firmware
allows combinations of front-panel buttons to perform
additional functions. For example, press the LOW ALARM
and the CAL CONST buttons to set the unit ID and press the
LOW ALARM and DEADTIME buttons to set the Port
number- 0 to 9999 = port 50000 – 59999. Consult the Ludlum
Model 375 Ethernet manual for further assistance.
Parameters are protected under a calibration cover. Calibration is easily
accomplished by moving the CAL dipswitch to the right, and using the
pushbuttons to increment or decrement the calibration constant, dead time
correction and alarm point parameters. Parameters are stored in non-volatile
memory (retained even with power disconnected).
A five-decade logarithmic analog output is provided. A battery backup provides
48 hours of additional use after the primary power is removed. The
Model 375-9 comes equipped with an external detector, able to detect gamma
radiation. Typical range is from 0.1 mR/hr to 1 R/hr (other ranges available)
Sectio
n
1
T

Model375-9 TechnicalManual Section1
Ludlum Measurements, Inc. Page 1-2 July 2016
Two common Model 375-9 systems with external detector are:
The Model 375-9 with Model 45-9 Ion Chamber
The Model 375-9 with Model 45-9-1 Ion Chamber Both detectors utilize a
stainless steel pressurized ion chamber with lead shielding for energy
compensation. An energy response curve is provided in the back of this
manual for quick reference.
Detector and electrometer are housed in an aluminum case. The electrometer
converts the detector signal to a pulse train for instrument recognition, and
generates the voltage for the detector anode

Model375-9 TechnicalManual Section2
Ludlum Measurements, Inc. Page 2-1 July 2016
Getting Started
he Model 375-9 Digital Wall-Mount Area Monitor is designed for
ease of use. This section of the manual is designed to help the first-
time user get started. Initial power-up and basic features of the
Model 375-9 will be discussed in this section. Other sections of the
manual provide more detailed information.
Unpacking and Repacking
Remove the calibration certificate and place it in a secure location. Remove
the instrument and ensure that all items listed on the packing list are in the
carton. Check individual item serial numbers and ensure calibration
certificates match between instruments and detectors (if applicable).
To return an instrument for repair or calibration, provide sufficient packing
material to prevent damage during shipment.
Every returned instrument must be accompanied by an Instrument Return
Form, which can downloaded from the Ludlum website at
www.ludlums.com. Find the form by clicking the “Support” tab and
selecting “Repair and Calibration” from the drop-down menu. Then choose
the appropriate Repair and Calibration division where you will find a link to
the form.
Notice!
Volume 49 of the Code of Federal Regulations
(Transportation) applies anytime a person is
transporting or offering for transport, a hazardous
material to, from or through the United States
United States law states that shipping of hazardous
materials/dangerous goods requires that each Hazmat
Employee as defined by 49 CFR 171.8, must receive
training and be tested in accordance with 49 CFR
172.700 – 172.704.
Sectio
n
2 T

Model375-9 TechnicalManual Section2
Ludlum Measurements, Inc. Page 2-2 July 2016
Connecting the Detector
The Model 375-9 comes equipped with either a Model 45-9 or 45-9-1 Ion
Chamber (detector). The instrument detector connector is located on the
bottom of the chassis. Use the cable provided to connect the detector to the
Model 375-9.
Power Up
Plug the power cord into a suitable wall (Mains) outlet.
Note:
Model 375-9 units will normally be wired internally for 120
VAC. If requested, the unit may be wired for 220 VAC.
Check the label next to the AC input receptacle to verify the
required input voltage.
If the RS-232 feature is used, plug in a suitably wired 9-pin connector cable.
(See Page 4-4 for the pin assignment of the 9-pin connector.) Turn power
ON with the left side panel switch. Do not turn power OFF unless the unit is
to be removed from service.
Read and then remove the sticker (illustrated to the
left) from the instrument calibration cover.
Checking and setting of the alarm-point(s) is
discussed in detail pages 2-2 and 7-1 of this manual.
Initial power-up will momentarily activate the
internal front panel lights, sound the audio, and
display "8888" on the 4-digit LED display. The
firmware version number (39665Nyy) is then
displayed as "396" and "65yy" (where yy represents
the current version number).
When the instrument has finished measuring background, it will display the
current radiation reading and begin checking for an alarm condition.

Model375-9 TechnicalManual Section2
Ludlum Measurements, Inc. Page 2-3 July 2016
Radiation Units
The Model 375-9 may be calibrated for almost any desired radiation units of
measure. Common units of measure include mR/hr, µR/hr, R/hr, mSv/h,
µSv/h, cps, cpm, and kcpm. In each case, the unit of measure is indicated
underneath the four-digit display. Throughout the rest of this manual, the
notation <units> will be used as a substitute.
Checking Parameters
Check the low alarm point setting by pressing the LOW ALARM button. The
low alarm point will be displayed as long as the button is pressed. The low
alarm point is in units of <units>. The low alarm point can be set from 0.1
<units> to 9999 <units>.
Check the high alarm point setting by pressing the HIGH ALARM button. The
high alarm point will be displayed as long as the button is pressed. The high
alarm point is in units of <units>. The high alarm point can be set from 0.1
<units> to 9999 <units>.
Check the calibration constant by pressing the CAL CONST button. The
calibration constant will be displayed as long as the button is pressed. The
calibration constant is in units of cpm (counts per minute) per <units>. The
calibration constant can be set from 0.1 cpm/<units> to 9999
cpm/<units>.
Check the detector dead time correction by pressing down on the DEAD
TIME button. The dead time correction will be displayed as long as the
button is pressed. The dead time correction is in units of microseconds. The
dead time correction can be set from 0.1 microseconds to 9999 micro-
seconds.
Check the background subtract parameter by simultaneously pressing both
LOW ALARM and HIGH ALARM buttons. This feature allows the user to set a
number to subtract from all measurements. This feature is necessary since
the ion chamber electrometer is normally set to output 400 cpm (6.67 cps) as
the zero reference.