Fluke 943-227-15, 943-27 User Manual

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Victoreen

Digital Preamplifier, Model 943-227-15,for use with

Model 943-27 Current Mode Beta Detector

Operator Manual

Fluke Biomedical

6045 Cochran Road Cleveland, Ohio 44139

440.498.2564

www.flukebiomedical.com

Table of Contents

Section 1: General Information............................................................................................................. 1-1

1.1 General Description ............................................................................................................... 1-1

1.2 Application.............................................................................................................................. 1-1

1.3 Specifications ......................................................................................................................... 1-2

1.4 Auxiliary Equipment ............................................................................................................... 1-6

1.5 Recommend Spare Parts.......................................................................................................1-6

1.6 Receiving Inspection .............................................................................................................. 1-6

1.7 Storage................................................................................................................................... 1-7

Section 2: Theory of Operation............................................................................................................. 2-1

2.1 Functional Description............................................................................................................ 2-1

2.2 Main Circuit Boards................................................................................................................ 2-1

2.3 977-200-15M Electrometer Board.......................................................................................... 2-1

2.4 977-210-10M Interface Board ................................................................................................ 2-4

2.5 Preamplifier Switch & Jumper Settings.................................................................................. 2-5

Section 3: Operation .............................................................................................................................. 3-1

3.1 Installation .............................................................................................................................. 3-1

3.2 Set-Up .................................................................................................................................... 3-2

3.3 Operation ............................................................................................................................... 3-3

3.4 Configuration Functions ......................................................................................................... 3-4

3.5 Set point Error Codes............................................................................................................. 3-5

3.6 Software Calculations ............................................................................................................ 3-5

Section 4: Maintenance, Calibration and Troubleshooting ............................................................... 4-1

4.1 Maintenance........................................................................................................................... 4-1

4.2 Calibration .............................................................................................................................. 4-1

4.3 Troubleshooting ..................................................................................................................... 4-2

Appendix A: Connector Designations .....................................................................................................A-1

A.1 Connector Designations......................................................................................................... A-1

Appendix B: Applicable Drawings............................................................................................................ B-1

B.1 Applicable Drawings............................................................................................................... B-1

Appendix C: Bill of Materials.....................................................................................................................C-1

C.1 Bill of Materials.......................................................................................................................C-1

Appendix D: Cable Termination Instructions..........................................................................................D-1

D.1 Cable Termination Instructions ..............................................................................................D-1

Appendix E: Modification Sheets/Engineering Instructions............................ .....................................E-1

E.1 Modification Sheets/Engineering Instructions........................................................................ E-1

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General Information

General Description

Section 1

General Information

1.1 General Description

The Victoreen® Model 943-227-15 Digital Preamplifier, is designed to operate with the Model 943-27, Current Mode Beta Scintillation detector and the Model 942A-200C Series Digital Ratemeter (UDR) or the Model 960 Series Digital Process Control system. When connected to the beta sensitive scintillation detector, it comprises a monitoring system which operates in the range of 10 Pico amperes). The UDR provides display, control, and annunciator functions for the monitoring system.

The preamplifier contains a microprocessor controlled, auto-zeroing, integrating electrometer, a programmable gain amplifier, an analog-to-digital converter and an asynchronous serial communications interface. Communications with the UDR is accomplished via the optically isolated Victoreen Serial Communication Loop driver/receiver circuitry.

Interconnection of the detector and preamplifier is accomplished utilizing two, six (6) foot coaxial cables. One cable supplies the high voltage for the detector (negative polarity). The other cable is used for the detector output signal. Interconnection between the preamplifier and the UDR or 960 system is accomplished via a six-conductor cable and a high voltage coaxial cable.

The detector operates at a potential of approximately (-) 500 VDC, and produces a nominal DC output current of 1 x 10 this corresponds to a range of 1 x 10

The preamplifier is a self-contained electronics unit that processes the DC input signal from the detector, digitizes the signal, and transmits the digitized value to the readout via a modified RS232C compatible serial data communication port. It contains two printed circuit boards (mounted on the rear of the enclosure cover, a terminal block for terminating the field cable from its associated controller and two connectors for terminating the detector Signal and HV coaxial cables. The larger of the two printed circuit boards is the 977-210-10M Serial Interface board. This board controls the communications with the controller. The smaller board is the 977-200-15M Electrometer. It contains the microprocessor and associated circuitry for converting the detector output current into a digital value.

For additional information on the detector or readout device, refer to the instruction manual for the Model 943-27-31 detector, the Model 942A-200C UDR, or the applicable Model 960 System manual.

-12

amperes to 1 x 10

-4

amperes. Depending on sampling geometry and detector set up,

-3

to 1 x 10

uCi/cc.

-3

to 105 uCi/cc (or 1E0 to 1E8

1.2 Application

The Model 943-227-15 Digital Preamplifier is used with the Victoreen 942A-200C or Model 960 microprocessor based radiation monitors. The Model 942A-200C or 960 system provides the +15 VDC preamplifier electronics power, (-) 500 VDC detector power and the RS232C serial communications support. The digital preamplifier is available in two serial port configurations. For applications less than 50 feet, the Model 943-227-15, configured for RS232C communications, is used. For applications requiring signal transmission distances of up to 1 mile, the Model 943-227-15VL, configured for Victoreen Loop communications is used. Table 1-1 is a list of available configurations and compatible 9XX series equipment. Please contact Fluke Biomedical Radiation Management Services for additional information.

943-227-15 Digital Preamplifier

Operator Manual

Table 1-1. 943-227-15 Variations and Compatible Equipment

Preamplifier Variations

943-227-15 Digital Preamplifier

943-227-15VL Digital Preamplifier

943-227-15VL-M1 Digital Preamplifier

Application Detector Readout

Transmission Distances Less than 50 feet

Transmission Distances up to 1 mile

Transmission Distances up to 1 mile; 2.0 inch conduit field cable interface

943-27-31 Beta Detector, Current Mode Operation

942A-200C Digital Ratemeter or Model 960 Digital Process Control System

1.3 Specifications

General specifications for the Model 943-227-15 Digital Preamplifier are listed below. The 943-227-15 series products are designed for nuclear applications, and any repairs to it by personnel not qualified to ANSI 45.2.6 1978, Skill Level II may void the nuclear rating.

If a problem develops, the preamplifier may either be returned to the factory for service, or repaired by a qualified technician.

1-2

Table 1-2. General Specifications for the 943-227-15 Digital Preamplifier

Feature: Specification:

Preamplifier Power

Preamplifier Input

Preamplifier Output

Electronic Accuracy

Response Time

Dimensions (H x W x D)

Weight

Housing

Operating Temperature

Relative Humidity

Compatible Detectors

Detector Interface

Cable Requirements

Modification Information

+ 15 v @ 20 mA DC current, 1E-12 to 1E-3 amperes from 943-27 Current Mode Beta

Scintillation detector 943-227-15, RS232C; 943-227-15VL, Modified RS232C serial data for transmission distances up to 5,280 feet.

± 10% of the input current Decade / Time:

1 / 80 sec 2 / 32 sec 3 / 16 sec 4 / 4 sec 5 / 2 sec 6 / 0.9 sec 7 / 0.2 sec 8 / 0.2 sec

943-227-15 or 943-227-15VL:

8.0 in. x10.0 in. x 4.0 in. (20.3 cm x 25.4 cm x 10.2 cm)

943-227-15-M1 or 943-227-15VL-M1:

8.0 in. x10.0 in. x 6.0 in. (20.3 cm x 25.4 cm x 15.2 cm)

Approximately 8 lbs. (3.6 kg)

Gasketed, NEMA 4, Steel enclosure with hinged cover 32 °F to 122 °F

0 °C to + 50 °C 0 to 99 % non-condensing

Victoreen 943-27 Current Mode Beta scintillation detector only Detector cables enter thru “Seal Grip” fittings; Mating SHV receptacle

provided for HV; Mating BNC receptacle provided for Signal Victoreen Loop Communications: 6 conductors, 18 AWG (2, TwPr, 2 Single conductor) with overall shield. For max transmission distance, 16 AWG is recommended; RS232C communications: 8 Conductors, 18 AWG (4 TwPr) with overall shield. For the Model 943-227-15VL-M1, refer to Modification description provided in Appendix E

General Information

Application

1-3

943-227-15 Digital Preamplifier

Operator Manual

Table 1-3. Preamplifier Serial Interface Board 977-210-10M Switch Settings

Switch Normal

Op.

SW1 Open Microprocessor Reset switch, momentary contact SW2 N/A Not supplied SW3-1 ON OFF Selects 300 baud • 1/ON Selects 4800 baud (normal setting)

SW3-2 OFF OFF • (No function is implemented in the 977-210-10M) SW3-3 OFF OFF Selects Rate Mode (normal) • (Selects Maintenance Mode for

SW3-4 OFF OFF • (No function is implemented in the 977-210-10M)

Switch Function

factory PGA and Auto Zero set-up only)

NOTE

SW3 is a 4-position DIP switch on the 977-210-10M serial interface board.

Table 1-4. Jumper Positions for Preamplifier Serial Interface Board 977-210-10M

Jumper Normal Setting Function Alternate Setting Function

JMP1 A to B JMP2 N/A Deleted, Not Used N/A Deleted, Not Used

Table 1-5. Jumper Positions for Preamplifier Electrometer Board 977-200-15M

Jumper Normal Setting Function Cal. Position Function

JMP1 A to B Normal Operation B to C PGA Offset Adjust *

* Programmable Gain Amplifier requires a special test PROM and is a factory adjustment

Enables Victoreen Loop (normal)

B to C Enables RS232C

1-4

Table 1-6. Field Electrical Connections, 943-227-15 and 943-227-15VL

General Information

Specifications

943-227-15

TB1- Description

1 XMIT

2 DTR

3 GND

4 REC

7 + 15 VDC J3-7 Not Used

8 Ground

9 - 15 VDC J3-4 Not Used Not Used

10 Not Used Not Used Not Used J3-11

HV Detector MHV

SIG Detector BNC

Table 1-7. 977-210-10M LEDs

LED # Indicates

LED1 +15 VDC is being supplied to the circuit board LED2 Communications – Receive;

Table 1-8. 977-210-10M Test points

Test Point Function

TP2 RS232 Transmit

Not Used

Detector

Connections

from the UDR when ON ON (bright): both + 15 and -15 volt loops

present ON (dim): Only one loop supply present OFF: no loop voltage from either supply

Connects To

977-210-10M

J4-1

J4-2 J4-3 J4-4

Not Used Not Used

J3-8

From Field

coaxial cable

Factory

Terminated,

To 977-200-

15M, R41

943-27-15VL

Description

+ VL, 15

VDC + TX

- TX

- VL

+ RX

- RX

Ground

Detector

Connections

Detector

MHV

Detector

BNC

Connects To

977-210-10M

J3-1

J3-2

J3-3

J3-4

J3-5 J3-6

Not Used

J3-8

From Field

coaxial cable

Factory

Terminated,

To 977-200-

15M, R41

943-227-15 Digital Preamplifier

Operator Manual

1.4 Auxiliary Equipment

Model Description

None

1.5 Recommended Spare Parts

Table 1-9. Recommended Spare Parts List for the Model 943-227-15 Digital Preamplifier

Part Number Description Used On

977-200-15M Electrometer Circuit Board -

977-210-10M Serial Interface Circuit Board -

92-7072 Fuse, F1, F2, 1Amp, Communication Fuse

450-1-0531 Dryer, Air (5 Grams)

977-210-10M

977-200-15

1.6 Receiving Inspection

Upon receipt of the unit:

1. Inspect the carton(s) and contents for damage. If damage is evident, file a claim with the carrier and notify the Fluke Biomedical Radiation Management Services Customer Service Department.

Fluke Biomedical

Radiation Management Service

6045 Cochran Road

Cleveland, Ohio 44139

Phone: 440.248.9300

Fax: 440.542.3682

2. Remove the contents from the packing material.

3. Verify that all items listed on the packing list have been received and are in good condition.

NOTE

If any of the listed items are missing or damaged, notify the Fluke Biomedical Radiation Management Service Customer Service Department.

1-6

General Information

Spare Parts/Receiving Inspection

1.7 Storage

Storage of Fluke Biomedical instruments must comply with Level B storage requirements as outlined in ANSI N45.2.2 (1972) Section 6.1.2(.2). The storage area shall comply with ANSI N45.2.2 (1972) Section

6.2 Storage Area, Paragraphs 6.2.1 through 6.2.5. Housekeeping shall conform to ANSI N45.2.3 (1972).

Level B components shall be stored within a fire resistant, tear resistant, weather tight enclosure, in a well-ventilated building or equivalent.

Storage of Fluke Biomedical instruments must comply with the following:

1. Inspection and examination of items in storage must be in accordance with ANSI N45.2.2 (1972) Section 6.4.1.

2. Requirements for proper storage must be documented and written procedures or instructions must be established.

3. In the event of fire, post-fire evaluation must be in accordance with ANSI N45.2.2 (1972), Section

6.4.3.

4. Removal of items from storage must be in accordance with ANSI N45.2.2 (1972), Sections 6.5 and

6.6.

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Theory of Operation

Functional Description

Section 2

Theory of Operation

2.1 Functional Description

The Model 943-227-15 Digital Preamplifier is an eight-decade, linear reading radiation. The preamplifier is sensitive to moisture and is mounted in a NEMA 4 sealed enclosure. The preamplifier box contains a desiccant package to remove moisture from the interior of the preamplifier. The desiccant has a color indicator to show when it should be replaced when the color changes to blue.

The detector electrometer converts the current from the detector to a voltage which is measured by the analog to digital converter of the preamplifier. Under program control, this measurement is made every 50 milliseconds on the first five decades and every 100 milliseconds on the upper three decades.

The electrometer is auto-ranging and auto-zeroing. An internal coarse zero control (factory adjusted) is provided. The microprocessor in the preamplifier performs data collection, integration and multiplication by a stored calibration factor, range changing and communication with the Model 942A-200C Digital Ratemeter or Model 960 Digital Process Radiation monitoring system.

2.2 Main Circuit Boards

The wide range ion chamber detector block diagram is shown in figure 2-1. Detector electronics are contained within two circuit board assemblies located in the preamplifier enclosure: the 977-210-10 High Voltage/Communications Interface circuit board assembly and the 977-200-15 Electrometer circuit board assembly. Schematic diagrams are located in Appendix B.

The 977-200-15M Electrometer circuit board contains the microprocessor, the EPROM, the integrating electrometer, the programmable gain amplifier, the analog to digital (A/D) converter, and the auto zero DAC circuit.

The 977-210-10M Communications Interface circuit board contains the dc voltage regulator, the BDC/DC converter, the asynchronous communication interface adapter (ACIA), the Victoreen communication loop driver/receiver, the RS232 communications driver/receiver, and the communication loop fuses.

2.3 977-200-15M Electrometer

Refer to the electrometer schematic 977-200-18M located in Appendix B. Z7 is a Texas Instruments TMS 70C00 microprocessor, which is utilized to control detector operation. Z8 latches port C of the microprocessor to form the lower order bits of memory address. Z10 is a 27C64 EPROM containing the operational firmware for the detector. Z18 is an optional RAM socket which is not utilized for this model detector. Z9 is a decoder for the upper order address bits. Z11 is a latch used to store control bits to select the gain of the programmable gain amplifier formed by the combination of Z5, Z4, and RN2. Available gains are 1 through 128 in binary increments 1, 2, 4, . . . 128. Z3 is an eight-bit analog to digital converter used to digitize the output of the programmable gain amplifier. Analog switch Z17 pin 11 selects either the integrating electrometer or the high voltage sense line as the input to the programmable gain amplifier is not active in this application. Refer to Table 2-1 for preamplifier register addresses and Table 2-2 for electrometer control bit assignments.

2-1

943-227-15 Digital Preamplifier

Operator Manual

0/-12 Vdc

0 - 10 Vdc

INTEGRATING ELECTROMETER

SIGNAL

DETECTOR ASSEMBLY

PGA

ANALOG SWITCH

HIGH VOLTAGE

MICROPROCESSOR CONTROL

SIGNAL

ALARM OUTPUT

Resistor

DAC EPROM

ADC

HIGH VOLTAGE POWER SUPPLY

RS232

Figure 2-1. Typical Detector Electronics Block Diagram

Table 2-1. Preamplifier Register Addresses

Function Hex Address

Electrometer Control 2000 ADC Convert CMD 4000 ADC Read Data 6000 ACIA T/R Data A000 ACIA Status Register A001 ACIA Command Register A002 ACIA Control Register A003 Input SW3 A008 RAM (not used) C000-DFFF EPROM E000-FFFF

CONTROL

MICROPROCESSOR

+VL

VICO LOOP

+TX

-TX

+RX

-RX

-VL

ACIA

2-2

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