Ludlum Measurements 2242 User manual

LUDLUM MODEL 2242
SURVEY METER
November 2010
Serial Number 219764 and Succeeding
Serial Numbers

LUDLUM MODEL 2242
SURVEY METER
November 2010
Serial Number 219764 and Succeeding
Serial Numbers
LUDLUM MEASUREMENTS, INC.
501 OAK STREET, P.O. BOX 810
SWEETWATER, TEXAS 79556
325-235-5494, FAX: [phone]

STATEMENT OF WARRANTY
Ludlum Measurements, Inc. warrants the products covered in this manual to be free of
defects due to workmanship, material, and design for a period of twelve months from the
date of delivery. The calibration of a product is warranted to be within its specified
accuracy limits at the time of shipment. In the event of instrument failure, notify Ludlum
Measurements to determine if repair, recalibration, or replacement is required.
This warranty excludes the replacement of photomultiplier tubes, G-M and proportional
tubes, and scintillation crystals which are broken due to excessive physical abuse or used
for purposes other than intended.
There are no warranties, express or implied, including without limitation any implied
warranty of merchantability or fitness, which extend beyond the description of the face
there of. If the product does not perform as warranted herein, purchaser’s sole remedy
shall be repair or replacement, at the option of Ludlum Measurements. In no event will
Ludlum Measurements be liable for damages, lost revenue, lost wages, or any other
incidental or consequential damages, arising from the purchase, use, or inability to use
product.
RETURN OF GOODS TO MANUFACTURER
If equipment needs to be returned to Ludlum Measurements, Inc. for repair or calibration, please send to
the address below. All shipments should include documentation containing return shipping address,
customer name, telephone number, description of service requested, and all other necessary information.
Your cooperation will expedite the return of your equipment.
LUDLUM MEASUREMENTS, INC.
ATTN: REPAIR DEPARTMENT
501 OAK STREET
SWEETWATER, TX 79556
800-622-0828 325-235-5494
FAX [phone]

Ludlum Measurements, Inc. November 2010
Table of Contents
Introduction 1
Getting Started 2
Unpacking and Repacking 2-1
Battery Installation 2-1
Operating the Instrument 2-2
Principle of Operation 2-2
Specifications 3
Description of Controls and Functions 4
Operator Controls 4-1
Internal Controls 4-2
Display 4-3
Safety & Maintenance Considerations 5
Environmental Conditions for Normal Use 5-1
Cleaning Instructions and Precautions 5-1
Warning Markings and Symbols 5-1
Maintenance 5-2
Recalibration 5-3
Batteries 5-3
Setup and Calibration 6
Entering or Changing Switch Board Parameters 6-1
The Function Switch 6-1
Function Switch Position Descriptions and Variables 6-2
Calibration 6-4
General Detector Setup Information 6-4
Exposure Rate Calibration 6-4
Detector Overload (OVL) Calibration 6-5
Loading Default Parameters 6-6

MODEL 2242 Technical Manual
Ludlum Measurements, Inc. November 2010
Troubleshooting 7
Technical Principle of Operation 8
Recycling 9
Parts List 10
Model 2242 Survey Meter 10-1
Main Board, Drawing 408 × 223 10-1
Calibration Board, Drawing 408 × 229 10-3
Display Board, Drawing 408 × 79 10-4
Switch Board, Drawing 408 × 46 10-4
Wiring Diagram, Drawing 408 × 221 10-5
Drawings and Diagrams 11

MODEL 2242 Technical Manual Section1
Ludlum Measurements, Inc. Page 1-1 November 2010
Introduction
he Model 2242 is a portable microprocessor-based digital Ratemeter
designed for detection and measurement of ionizing radiation. The
data is presented on a 4-digit Liquid Crystal Display (LCD). A 3-
position switch labeled “OFF/LOW (mR/h)/HIGH (R/hr)” selects
the desired operating range for the instrument. The internal detectors are
energy-compensated GM (Geiger-Mueller) tubes capable of measuring fields
from 0.01 mR/hr to 999.9 R/hr.
This instrument incorporates independent adjustable alarms for each range.
The first-level alarm is indicated by ALERT on the LCD. Display of ALARM
on the LCD, a continuous audible tone and an illuminated alarm LED (red)
indicate the second-level alarm. Both audible alarms can be silenced
(acknowledged) by depressing the RESET switch.
Other features include Dead Time Correction (DTC) to compensate for
detector dead time; audible click-per-event with programmable 1, 10, 100,
and 1000 divide-by; LCD backlight with programmable ON time;
programmable fixed or variable response time; and count overflow visual
alarm indicating that the counting circuitry is nearing the maximum counting
capability.
All of the features described above may be programmed manually, using the
internal switch board, or by computer through the RS-232 port. The switch
board can be removed after entering or changing parameters to prevent
undesired altering of setup parameters.
A regulated high voltage power supply, dual set points adjustable from 400
to 2500 volts, with detector overload detection add versatility to the
instrument. A single adjustable discrimination setting applies to both internal
detectors. All calibration controls are covered to prevent any inadvertent
altering of the detector operating parameters.
Section
1
T

MODEL 2242 Technical Manual Section1
Ludlum Measurements, Inc. Page 1-2 November 2010
The instrument operates on two ˝D˝cell flashlight batteries. The unit body
is made of cast-and-drawn aluminum and is covered in beige powder-
coating to aid in surface decontamination.

MODEL 2242 Technical Manual Section2
Ludlum Measurements, Inc. Page 2-1 November 2010
Getting Started
Unpacking and Repacking
Remove the calibration certificate and place it in a secure location. Remove
the instrument and accessories (batteries, cables, etc.) and ensure that all of
the items listed on the packing list are in the carton. Check individual item
serial numbers and ensure calibration certificates match. The Model 2242
serial number is located on the front panel below the battery compartment.
To return an instrument for repair or calibration, provide sufficient packing
material to prevent damage during shipment. Also provide appropriate
warning labels to ensure careful handling. Include detector(s) and related
cable(s) for calibration. Include brief information as to the reason for return,
as well as return shipping instructions:
- Return shipping address
- Customer name or contact
- Telephone number
- Description of service requested and all other necessary
information
Battery Installation
Ensure that the range selector switch is in the ˝OFF˝position. Open the
battery lid by pushing down and turning the quarter-turn thumbscrew
counterclockwise ¼ turn. Install two ˝D˝size batteries in the compartment.
Note the (+) and (-) marks inside the battery door. Match the battery
polarity to these marks. Close the battery box lid, push down and turn the
quarter-turn thumb screw clockwise ¼ turn.
Note:
Center post of a flashlight battery is positive. The batteries are
placed in the battery compartment in opposite directions.
Section
2

MODEL 2242 Technical Manual Section2
Ludlum Measurements, Inc. Page 2-2 November 2010
Operating the Instrument
Turn the OFF/LOW(mR/hr)/HIGH(R/hr) switch to the
LOW(mR/hr) position. The display goes through an
initialization sequence. The display will show all “8”s
with decimal points. Check to make sure all segments are
on, as illustrated to the left.
The LCD then shows the firmware number in the
format “P-XX YY.” The “XX” is the firmware number,
and the “YY
Select the desired AUD ON/OFF parameter and proceed
to use instrument. Switch up to the R/hr range only if the
OFLOW and/or OVERLOAD symbols are displayed, or if
the display shows 999 mR/hr.
” is the firmware version. (The figure to the
left is for example only, to illustrate location of display.)
Principle of Operation
The Model 2242 utilizes microprocessor-based technology, providing an
extensive range of operating features. Two independent detector parameters
can be stored in memory (with the exception of a single discrimination
parameter).
The Model 2242 incorporates a detachable switch board used to program
detector and operating parameters into non-volatile memory (retains the
data even after the power is removed). The switch board may be removed so
that the operating parameters cannot be altered. If multiple units are to be
used at one location, fewer Switch Boards may be purchased in order to
program all instruments. A 16-position rotary switch (FUNCTION) selects
each of the 16 operating/detector parameters. Three pushbutton switches
on the Switch Board provide the means to change and save the variables for
each of the parameters.
An RS-232 port is also available via the switch board for computer
connection. An optional can with the RS-232 connector mounted externally
is also available. Communication baud rate may be set with the FUNCTION
switch to correspond to the computer baud. The computer can adjust the
detector parameters and retrieve data.

MODEL 2242 Technical Manual Section2
Ludlum Measurements, Inc. Page 2-3 November 2010
An LCD provides the readout for the
ratemeter data with the programmed units
and multipliers, as well as ALERT, ALARM,
OVERLOAD and OVERFLOW annunciators,
"low battery" icon, and scaler counting
mode indication (COUNTING – not used). The four 0.5" digits are used for
the ratemeter data. The LCD also displays the variables during the manual
programming sequence. (See figure above.) A front panel alarm LED (red)
illuminates during an alarm condition.