Related Manuals for LUDLUM 375 Series
Summary of Contents for LUDLUM 375 Series
- Page 1 LUDLUM MODELS 375 (INCLUDING SERIES ONE), 375/2, 375/4, AND 375WT DIGITAL WALL-MOUNT AREA MONITORS May 2021 Serial Number 179939 and Succeeding Serial Numbers Legacy Version...
- Page 2 LUDLUM MODELS 375 (INCLUDING SERIES ONE), 375/2, 375/4, AND 375WT DIGITAL WALL-MOUNT AREA MONITORS May 2021 Serial Number 179939 and Succeeding Serial Numbers Legacy Version...
- Page 4 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.
-
Page 7: Table Of Contents
Table of Contents Introduction Getting Started External Detector (Option) Power Up Radiation Units *Model 375 Series One Checking Parameters Setting Alarm-points Operational Check Specifications Operator Controls and Setup Calibration Controls Dipswitch (under calibration cover) RS-232 Output 9-Pin Data Connector Typical Internal Detector Setups... - Page 8 Parts List Model 375 Digital Wall-Mount Area Monitor without Detector Model 375/2 Digital Wall-Mount Area Monitor Model 375/4 Digital Wall-Mount Area Monitor Model 375 Series One without Detector Model 375/2 Series One Model 375/4 Series One Model 375WT without Detector Main Board, Drawing 396 ×...
-
Page 9: Introduction
The Model 375/2 with an internal LND 71210 detector. The Model 375/4 with an internal LND 71412 detector. The Ludlum Model 375 Series One is a Model 375 with modified firmware. Changes include certain display values in decimal points and units. Details can be found in sections ˝Getting Started˝... -
Page 10: Getting Started
Improper termination will result in the “shorting-out” of the detector voltage, a and/or blown-fuse condition. DET FAIL Power Up Plug the power cord into a suitable wall (Mains) outlet (see note on following page). Ludlum Measurements, Inc. Page 2-1 May 2021... -
Page 11: Radiation Units
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. Ludlum Measurements, Inc. Page 2-2 May 2021... -
Page 12: Model 375 Series One
Models 375 (Including Series One), 375/2, 375/4 & 375WT Legacy Section 2 : In the special case of the Model 375 Series One Model 375 Series One make note of the following changes resulting from firmware modification: With the dipswitch in the left position (normal operating mode), two decimal places will be displayed instead of one. -
Page 13: Operational Check
The operational check is an important assurance that the radiation detector and electronics are working correctly. Note: Ludlum Measurements suggests that an operational check be performed on a regular basis. Local procedures may supersede this suggestion. For an operational check it is necessary to use a radiation check source (not included, but available). - Page 14 Verify that the reading is within 20% of the last reading obtained. Remove the source from the detector. 3. If an alarm is activated, ensure that all visual and audible devices (if applicable) work correctly. Ludlum Measurements, Inc. Page 2-5 May 2021...
-
Page 15: Specifications
: Indicated by a red light and an audible tone greater than 68dB DET Fail at 2 feet for conditions of detector overload, no count from detector or instrument failure. Ludlum Measurements, Inc. Page 3-1 May 2021... - Page 16 RS-232 Output : A 2-second dump for computer data logging. Remote (optional) : Ludlum Model 271 or 272 remote units. : 95-135 VAC (178-240 VAC available), 50-60 Hz single phase Power (less than 100 mA), 6 volt sealed lead acid rechargeable backup battery (built-in).
- Page 17 Models 375 (Including Series One), 375/2, 375/4 & 375WT Legacy Section 3 : Aluminum housing with ivory powder-coat finish. Construction : 9.7" (24.6 cm) W × 7.4" (18.7 cm) H × 2.5" (6.4 cm) D Size : 5.2 lb. (2.4 kg) Weight Ludlum Measurements, Inc. Page 3-3 May 2021...
-
Page 18: Operator Controls And Setup
: Internal discriminator used to set pulse threshold for counting pulses from the detector. Pad allows direct measurement of threshold voltage. Utilize a Ludlum Model 500 Pulser or equivalent to inject pulses of the desired threshold size. The pulse height threshold is adjustable from 2.0 mVdc to 100 mVdc. -
Page 19: Dipswitch (Under Calibration Cover)
Model 375 dumps RS- CAL MODE 232 data onto pin 4 of the 9-pin connector every two seconds. The communication parameters are 2400 baud, 8 data bits, no parity, 1 stop bit, and no hardware handshaking. Ludlum Measurements, Inc. Page 4-2 May 2021... -
Page 20: 9-Pin Data Connector
Linear Range with DTC: 0.1 mR/hr - 1 R/hr Typical Checkpoints: 1 mR/hr 4 mR/hr 8 mR/hr - calibration constant set point 40 mR/hr 80 mR/hr 400 mR/hr 800 mR/hr - dead time correction set point 1,000 mR/hr Ludlum Measurements, Inc. Page 4-3 May 2021... - Page 21 Linear Range with DTC: 1 mR/hr - 8 R/hr Typical Checkpoints: 4 mR/hr 8 mR/hr 40 mR/hr - calibration constant set point 80 mR/hr 400 mR/hr 800 mR/hr 4,000 mR/hr - dead time correction set point 8,000 mR/hr Ludlum Measurements, Inc. Page 4-4 May 2021...
-
Page 22: Common Options And Modifications
Check the hours and minutes (HHMM) by pressing the LOW ALARM buttons simultaneously. The hours and minutes will be DEAD TIME displayed as long as those buttons are pressed. The hours and minutes can be adjusted from 0000 to 2359. Ludlum Measurements, Inc. Page 5-1 May 2021... -
Page 23: Relay Options
1 amp. The relay can be configured as a set of Form C contacts or as mains (120 VAC) output. The signal or contacts can be brought out through a 3 pin connector on the bottom of the chassis. Ludlum Measurements, Inc. Page 5-2 May 2021... -
Page 24: Sigma Alarm Modification Option
38 days. To actually calculate the sigma alarm point, it is necessary first to determine the background radiation level in cps (counts per second). The sigma alarm point is then BKGND + (x sigma × square root of BKGND). Ludlum Measurements, Inc. Page 5-3 May 2021... -
Page 25: To 20 Ma Isolated Output Driver Option
RAWDC of the Model 375. It is designed for a 2-wire configuration, with one conductor carrying the 4-20 mA current signal and the second conductor providing a return (isolated loop ground). See Wiring Diagram, Figure 1 (below). Figure 1: Wiring Diagram. 5396-754 Ludlum Measurements, Inc. Page 5-4 May 2021... - Page 26 The voltage at full-scale must be set to 5.00 V ±0.1 V between the analog input and instrument ground. Note: Instrument ground is not the same as loop ground. Ludlum Measurements, Inc. Page 5-5 May 2021...
-
Page 27: Waste Truck (Model 375Wt) Modification
R432 changes from 100k to 1Meg; LMI Part Number 12-7844. Waste Truck (Model 375WT) Modification The Ludlum Model 375WT Digital Waste Truck Monitor is a Model 375 modified to be powered by a +12 Vdc power supply. This modification allows the instrument to connect to a truck battery or charging system. The instrument will, however, also work if connected to Mains (120 VAC) through the standard AC connector. -
Page 28: Safety Considerations
Do not immerse the instrument in any liquid. Observe the following precautions when cleaning: 1. Turn the instrument and disconnect the instrument power cord. 2. Allow the instrument to sit for 1 minute before cleaning. Ludlum Measurements, Inc. Page 6-1 May 2021... -
Page 29: Warning Markings And Symbols
Caution! The operator or responsible body is cautioned that the protection provided by the equipment may be impaired if the equipment is used in a manner not specified by Ludlum Measurements, Inc. The Model 375 is marked with the following symbols: CAUTION, RISK OF ELECTRIC SHOCK (per ISO 3864, No. -
Page 30: Replacement Of Main Fuse
1 minute! Battery Replacement Warning!: Only certified technicians or calibration personnel should replace battery. Ludlum Measurements, Inc. Page 6-3 May 2021... - Page 31 Models 375 (Including Series One), 375/2, 375/4 & 375WT Legacy Section 6 Note: Ludlum Measurements, Inc. recommends replacing batteries every four years. Ludlum Measurements, Inc. Page 6-4 May 2021...
-
Page 32: Calibration
"low" radiation field. A "low" radiation field in this case is defined as a field where dead time losses do not exceed 5%. The calibration constant is usually given for a certain detector. A Ludlum Model 133-4 detector, for example, has a calibration constant of approximately 150 cpm/mR/hr. Once the calibration constant is set and checked at a low radiation field, the dead time correction can be set. -
Page 33: Analog Output
Battery Charge The potentiometer labeled , located under the calibration cover, is used to set the backup battery trickle charge voltage. This is typically set to 6.9 Vdc with the battery disconnected. Ludlum Measurements, Inc. Page 7-2 May 2021... -
Page 34: Recycling
To this end, Ludlum Measurements, Inc. strives to supply the consumer of its goods with information regarding reuse and recycling of the many different types of materials used in its products. With many different agencies, public and private, involved in this pursuit it becomes evident that a myriad of methods can be used in the process of recycling. -
Page 35: Parts List
Mount Area Monitor UNIT Completely Assembled Model 375/4 Digital Wall- Model 375/4 48-2411 Mount Area Monitor UNIT Completely Assembled Model 375 Series One Model 375 Series One 48-2676 without Detector Model 375/2 Series One UNIT Completely Assembled Model 375/2 Series One 48-2931... - Page 36 MJD210 05-5843 Q652 MMBT3904T 05-5841 Q721 MMBT3904T 05-5841 VOLTAGE VR341 LT1129CQ-5 06-6372 REGULATOR INTEGRATED U031 SA08-11EWA 07-6389 CIRCUITS U032 HLMP-2785 07-6371 U041 HLMP-2685 07-6400 U111 ICM7218CIQI 06-6311 U131 SA08-11EWA 07-6389 U201 MAX220 06-6329 Ludlum Measurements, Inc. Page 9-2 May 2021...
- Page 37 5K, ANALOG ADJ 09-6948 RESISTORS R011 100, 1%, 125mW 12-7840 R041 10, 1/2W 11-7251 R042 60.4, 1%, 250mW 12-7962 R141 10, 1/2W 11-7251 R142 60.4, 1%, 250mW 12-7962 R151-R152 100K, 1%, 125mW 12-7834 Ludlum Measurements, Inc. Page 9-3 May 2021...
- Page 38 10.0K, 1%, 125mW 12-7839 R722 100K, 1%, 125mW 12-7834 R723 1.00K, 1%, 125mW 12-7832 R724 4.75K, 1%, 125mW 12-7858 R731 5.6M 10-7093 R732-R733 100K, 1%, 125mW 12-7834 R734 10-7028 R735 10.0K, 1%, 125mW 12-7839 Ludlum Measurements, Inc. Page 9-4 May 2021...
-
Page 39: Wiring Diagram, Drawing 396 × 176
FILTER CORCOM 3EHG1-2 21-9830 D RECPT-RD9F000V3 9 PIN 13-8003 SWITCH DM62J12S205PQ W/LEGEND 08-6715 TRANSFORMERS CFP302 115/230V 22-9908 BATTERY BATTERY-PS630 21-9705 Internal Detectors Model 375/2 (only) DET ASSY. 4396-055 Model 375/4 (only) DET ASSY. 4396-056 Ludlum Measurements, Inc. Page 9-5 May 2021... - Page 40 Models 375 (Including Series One), 375/2, 375/4 & 375WT Legacy Section 10 Section Drawings Main Circuit Board, Drawing 396 × 160 Main Circuit Board Component Layout Drawing 396 × 161A (2 sheets) Wiring Diagram, Drawing 396 × 176 Ludlum Measurements, Inc. Page 10-1 May 2021...
Need help?
Do you have a question about the 375 Series and is the answer not in the manual?
Questions and answers