Ludlum Model 2241-2 Digital Survey Meter / Scaler

This instrument is a general purpose, digital ratemeter with a built-in scaler that provides timed counts over a user specified period. This system will store detector setup information for up to two detectors so personnel can easily change detectors in the field. The LCD presents readings in a four-digit moving decimal format together with one of a wide range of available units of measure and is accompanied by several operational and alert icons. The LCD backlight can be activated and remains lit for a user-adjustable interval. This instrument features adjustable alert & alarm setpoints for both the Ratemeter and Scaler modes. Front-panel controls include a rotary switch for selecting between Off, Ratemeter Mode, and Scaler Mode, switches for audio on/off and fast/variable response time, and push buttons for activating the LCD backlight for either resetting the counts or acknowledging any alarms. A locking toggle switch facilitates swapping detectors while preventing accidental switching.

Similar models include the dual probe DSM-525 Survey Meter, with larger display and multiple units.




INDICATED USE: General purpose survey, gross counting
COMPATIBLE DETECTORS: G-M, proportional, scintillation
DET1/DET2: A locking toggle switch to allow for quick change between two detector setups
CONNECTOR: Series "C" (others available on request)
AUDIO: Built in unimorph speaker with ON/OFF switch (greater than 60 dB at 2 feet)
ALERT/ALARM: Indicated by enunciator on display and audible tone
DISPLAY: 4 digit LCD display with 0.5"(1.3cm) high digits, separate enunciators for display units, alert, alarm, low battery, detector overload, counting overflow, and scaler counting
BACKLIGHT: Push-button to activate
RATEMETER: Can display in R/hr, Sv/hr, cpm, or cps when control switch is in RATEMETER position
DISPLAY RANGE: Auto ranging from 0.0 microR/hr - 9999 R/hr; 0.000 microSv/hr - 9999 Sv/hr; 0 cpm - 999k cpm; or 0 cps - 100k cps
LINEARITY: Reading within plus or minus 10% of true value with detector connected
SCALER: Activated by push-button in handle (count time adjustable from 1 - 9999 seconds in 1 second intervals)
CALIBRATION CONTROLS: Accessible from front of instrument (protective cover provided)
HIGH VOLTAGE: Two independent controls, each adjustable from 200 - 2500 volts
DISCRIMINATOR: Two independent controls, each adjustable from 2 - 100 mV
OVERLOAD: Indicated by OVERLOAD on display (adjustable depending on detector selected)
RESET: Push-button to zero display, acknowledge and/or reset alarm
POWER: 2 each "D" cell batteries (housed in sealed compartment that is externally accessible)
BATTERY LIFE: Typically 200 hours with alkaline batteries (24 hours when low battery is first indicated on display)
CONSTRUCTION: Cast and drawn aluminum with beige polyurethane enamel paint
TEMPERATURE RANGE: -4° F(-20° C) to 122° F(50° C)
May be certified for operation from -40° F(-40° C) to 150° F(65° C)
SIZE: 6.5"(16.5cm)H X 3.5"(8.9cm)W X 8.5"(21.6cm)L
WEIGHT: 3.5 lbs (1.6kg) including batteries

The following parameters are adjusted by removable switchboard. Once initial setup and calibration have been completed the switchboard can be removed without affecting normal operation of the instrument (Model 2241-2 may be ordered without switchboard)

BACKLIGHT "ON" TIME: 5, 30, 60, 90, 180, or 240 seconds for the backlight to stay "ON" when activated.
SET MINIMUM DISPLAY: Allows lower limit of auto-ranging display to be fixed. For example, display can be set to not show values less than 1 R/hr.
RS-232 DATA DUMP MODE: Enables or disables dump mode to RS-232 port. When enabled data will be dumped every 2 seconds
RS-232 DETECTOR SETUP MODE: Allows for detector parameters to be input by RS- 232 port
BAUD RATE: 150, 300, 600, 1200, 2400, 4800, 9600, or 19200 bps.
DEAD TIME: Adjustable from 0 - 9999 seconds
CALIBRATION CONSTANT: Adjustable from 0.001 - 280 X 109 counts/display unit
DISPLAY UNITS: Can read in R/hr, Sv/hr, cpm, or cps
TIME BASE: Can read in seconds or minutes
AUDIO DIVIDE: 1, 10, 100, or 1000 events-per-click
     Fixed: FAST response time adjustable from approximately 2 - 50 seconds. SLOW response is 5          times fast setting
     Variable: Dependent on number of counts present. Typical times FAST - 4 - 25 seconds,          SLOW - 4-60 seconds
     (All times stated from 10% to 90% of final reading)
RATEMETER ALERT/ALARM: Set at any point corresponding to pre-selected ratemeter range
SCALER ALARM: Adjustable from 1 - 999999 counts
SCALER COUNT TIME: Adjustable from 1 - 9999 seconds

Waterproof Pelican Cases Available




For Alpha/beta/gamma Measurements

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Model 43-2
Model 43-5
Model 43-20
Model 43-44
Model 43-44-1
Model 43-65
Model 43-68
Model 43-90
Model 44-7
Model 44-9
Model 44-88
Model 44-89
Model 44-94

Model 43-20
Model 43-68
Model 44-1
Model 44-6
Model 44-7
Model 44-9
Model 44-21
Model 44-38
Model 44-88
Model 44-89
Model 44-92
Model 44-94
Model 44-98
Model 44-116

Model 44-2
Model 44-3
Model 44-6
Model 44-7
Model 44-9
Model 44-10
Model 44-17
Model 44-20
Model 44-21
Model 44-38
Model 44-62

Model 44-7
Model 44-9
Model 44-88
Model 44-89
Model 44-94

Model 2241 Series Digital Display



Replacement Parts

Check Source
Source Holder
Shoulder Strap
Standard Carrying Case
Air and Water Tight Carrying Case

Meter Bezel
LCD Display
Probe Clip




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