Model 2241-2

Digital Scaler-Ratemeter

Part Number: 48-2731

Features

Digital Ratemeter with Built-In Scaler
Auto-Ranging
Panel Mounted Locking Switch for Selecting Two Detector Setups
Adjustable Alarms
Wide Range HV
Overrange & Overload Protection

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 and 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 and for either resetting the counts or acknowledging alarms. A locking toggle switch facilitates swapping detectors while preventing accidental switching.

Specifications

Indicated Use	General purpose survey, gross counting
Compatible Detectors	GM, Proportional, Scintillation
Detector Setups	2
Linearity	Reading within 10% of true value with detector connected
Display	4-digit LCD display with 1.3 cm (0.5 in.) high digits, separate annunciators for display units, alert, alarm, low battery, detector overload, counting overflow, and scaler counting
Display Range	Auto ranging from: 0.0 μR/hr to 9999 R/hr 0.000 μSv/h to 9999 Sv/h 0 cpm to 999 kcpm 0 cps to 100 kcps
Backlight	Pushbutton to activate
Ratemeter	Can display in R/hr, Sv/h, cpm, or cps when selector switch is in RATE position
Scaler	Adjustable from 1 to 9999 s (in 1 s intervals)
Detector Switch	Two-way locking toggle switch
Alert/Alarm	Indicated by annunciation on display and audible tone
High Voltage	400 to 2400 V
Discriminator	Adjustable from 2 to 100 mV
Discriminator Adjustments	2
Temperature Range	-20 to 50 °C (-4 to 122 °F)
RS-232 Port	Available in two output formats: binary output or ASCII output. The ASCII output format option requires a firmware change (PN 4408-192).
Power	2 "D" cell batteries housed in an externally accessible, sealed compartment
Battery Life	Typically 200 hours with alkaline batteries (low battery warning on LCD)
Size (H x W x L)	16.5 x 8.9 x 21.6 cm (6.5 x 3.5 x 8.5 in.)
Weight	1.6 kg (3.5 lb), including batteries

Adjustable Parameters

The following parameters are adjusted for each detector by a removable switchboard. Once initial setup and calibration have been completed the switchboard can be removed without affecting normal operation of the instrument.

Backlight "ON' Time	5, 15, 30, 60, 90, 120, 180, or 240 seconds for 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 mR/hr.
RS-232 Data Dump Mode	Enables or disables binary dump mode to RS-232 port. When enabled binary 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
Detector Dead Time Compensation	Adjustable from 0 to 9999 µs
Calibration Constant	Adjustable from 0.001 to 280 x 10⁹ counts/display unit
Display Units	Can display in R/hr, Sv/h, cpm, or cps
Time Base	Can display in seconds or minutes
Audio Divide	1, 10, 100, or 1000 events-per-click
Response Time	Variable: Dependent on number of counts present. Typical times are FAST 4 to 25 s, SLOW 4 to 60 s (All times stated from 10% to 90% of final reading). Fixed: The parameter is adjustable from 1 to 25 resulting in a FAST response from approximately 2 to 50 s. The SLOW response is approximately 10 to 250 s. For MDA-type measurements, the fixed response mode is recommended.
Ratemeter Alert/Alarm	Set at any value within the effective range of each detector
Scaler Alarm	Adjustable from 1 to 999999 counts
Scaler Count Time	Adjustable from 1 to 9999 s

Options

Option	Description	Part Number
Shoulder Strap	Adjustable nylon shoulder strap.	4363-413
Headphone Jack	Adds headphone jack to instrument.	4464-464
Stereo/Mono Headphones	Adjustable stereo/mono headphones.	22-9313
Plastic Disk Check Sources	General purpose check sources used to check instrument response.	Depends on source material and activity.
Mechanical Check Source Holder	Check source holder with swing-away door that attaches to instrument housing.	4062-166
Check Sources With Stick-On Holder	Check source with adhesive holder that attaches to instrument housing.	Depends on source activity.

Replacement Parts

Description	Part Number
RS-232 Cable (9-pin)	8303-458
RS-232 Cable (25-pin)	8303-459
Meter Bezel	4408-051
Digital Display	5408-259
Rolled Handle	4408-075
Flat Handle	4408-090