2080 Manual REVB
Contents
1. 100 cts 256 Balance Constant g cts 256 In practice the instrument will be put into a gamma field for either a known period of time or until a certain number appears on the counter The more counts the better but too many may confuse the issue The Balance Constant can only be set in unit increments or about 196 adjustment When 1000 neutron counts are displayed the balance will read within or 1000 if the Balance Constant is within 1 With 1000 MODEL 2080 Health Physics Instruments counts in the display the instrument is easy to balance and the statistical errors of or 1 count are insignificant Then the SET UP DOWN switch is manipulated until the balance number is as close to zero as possible It will probably never be right on zero but as close to it is the goal slightly positive number will make the instrument read more neutrons in a high gamma field The SET UP DOWN switch is always working and can be moved at any time to change the Balance Constant and thus to change the balance The display is updated every second Once a significant number of counts have been accumulated and the Balance Constant adjusted satisfactorily the counters may be zeroed using the RESET A subsequent count may be used to demonstrate reliability and reproducibility but otherwise unnecessary Thatis all there is to balancing the instrument The next phase is to set the absolute Calibration Factor To do it push the LAM2. 210 jamoa 34 5 lt 20999 Q M X te lt Li S Ko lt lt lt lt o CL AY wany 8 3 8 Ce ase 32 Instruments 5 Health Phys MODEL 2080 aasa 56 41 031412345 3SIMU3HI0 5531 5310 33 Instruments 5 Health Phys MODEL 2080 ca CE 5 T ASSEMBLY READOUT ealth Ohvsics mslruments Disan OF Fi E HEHH H 4 H st EEH A HH REN 35 N 8 9 SAG 49 NOTES UNLESS OTHERWISE SPECIFIED Ey MODEL 2080 Health Physics Instruments MODEL 2080 Health Physics Instruments 7 3 uj 4 lt 8 ents health strum P NOTES UNLESS OTHERWISE SPECIFIED p ioe oon
3. 2080 020 BUSSMAN 2080 020 BUSSMAN 2080 020 EM PROT D 2080 020 2080 020 HPI 2080 020 HPI 2080 020 2080 020 OKI 2080 020 KEKYSTONE EFJOHNSON MFG DRAWING 2080 020 2080 020 2080 020 2080 020 2080 020 2080 020 2080 020 2080 020 HPI 2080 020 HPI 2080 020 HPI 2080 020 2080 020 2080 020 2080 020 2080 020 2080 020 2080 020 2080 020 RICHCO 2080 021 TUBE SALES 2080 022 27 MODEL 2080 Health Physics Instruments XVII SCHEMATICS 28 5 30455133 anans gt 224 Gu sw 2 sue vet e 2 E 00 gt s m Yg Orb gt 22 Dur ml wos 1405 40 f 13 2 50 0 831412345 3SIMH3H10 5531 5310N 29 Health Physics Instruments MODEL 2080 1520 dO NNM 924 INOUN 2071 Sieve xe 031412345 V3H10 SSIINN gavos eaw 33035 IRATUM INE 031319345 3SIMH3H10 5531 5310N 8 MINYA OL 30 Health Physics Instruments MODEL 2080 I2 167 26 178 54 ANCOWEA DIVWSHIS A gt 554 5 v ponis s lt lt lt 75 lt 53 lt lt ez lt lt 9 824 sz lt
4. 1010 1011 1100 1101 Above the number 9 letters are used to represent the number The Binary equivalent of these numbers is the key to deciphering the status byte The C and the 2 above in the second status byte now begin to make more sense when their binary equivalents are written down one on top of the other STATUS BYTE in HEX C 2 BINARY EQUIVALENT 1100 0010 Bit number 7654 3210 The bit number below shows the location in the original byte of the individual bits For example bit 5 is 0 bit 7 is 1 etc It is now an easy matter to look up the individual bits the table above and figure out what they mean Bits number 1 6 and 7 are all high or 1 All the other bits are low or 0 From the table we see that bit 1 is the debounce bit bit 6 is the display average time bit and bit 7 is the calibrate bit Thus the instrument is debouncing the lamps switch while in the Average Time in the Calibrate mode MODEL 2080 Health Physics Instruments 20 XIII LOGOUT The LOGOUT signal is an analog voltage that is present on both the PSS connector and the AUX I O connector It is the logarithm of the digital radiation level that is displayed The LOGOUT as itis called has a finer resolution than the display While the display displays only units the LOGOUTS resolution is 1 4 mrem The LOGOUT signal therefore may not appear to follow the digital read out A better way to think of this is that the digital display follows the LOGOUT rather than
5. 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 VICTOREEN RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF TRANSFORMER HV MICROTRAN DUAL COMPARATOR NATIONAL VOLT CONV REG SWITCH MAXIM DUAL MONO VOLT REGULATOR NATIONAL GM TUBE DETECTOR LND GM TUBE DETECTOR LND BATTERY NICAD AA PANASONIC CAPACITOR MONO CERAM TRW CAPACITOR MONO CERAM TRW CAPACITOR ELECTROLY PANASONIC CAPACITOR MONO CERAM TRW DESCRIPTION MFG CAPACITOR ELECTRO RA PANASONIC CAPACITOR ELECTRO RA PANASONIC CAPACITOR MONO CERAM TRW CAPACITOR TANTALUM PANASONIC CAPACITOR ELECTRO R PANASONIC CAPACITOR ELECTRO R PANASONIC 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 011 2080 014 2080 014 2080 014 2080 014 2080 014 DRAWIN
6. A description of each plug from left to right while looking at the back panel is as follows A POWER CONNECTION The rectangular line cord connector plugs into an IEC 320 cordset The instrument is designed for 110 VAC 60 Hz B FUSE The fuse holder contains a 1 4 A 3AG Fuse To remove the fuse unplug the line cord Push in on the fuse holder and turn counter clockwise The end cap will come loose along with the fuse Reassembly is just the opposite but replace the fuse with a new one C PSS The 6 pin circular connector is a connection for the Personal Safety System This in an interlock connection for use when the instrument is used as an area monitor MODEL 2080 Health Physics Instruments D AUX I O This 25 pin DB connector has several outputs including buffered GM tube counts an analog LOGOUT signal of the radiation level an RS 232A output of the radiation level and instrument parameters and power and reserved function pins Its use is primarily in system expansion and testing E HEAD This 9 pin DB connector goes to a cable that in turn plugs into the head If this cable is not installed the instrument will work but will show a FAIL The instrument should be turned off when connecting or removing this cable either from the read out or the head No harm will come to any electronics if the instrument is on while the cable is attached or removed but the program may not operate properly J ust turn the instrument on an
7. Constant This number is raised and lowered by the SET UP DOWN switch on the front panel Push the SET UP DOWN switch up and hold it there and every second the number will increase by one Hold it down and the number will go down by 1 every second This is the way the Balance Constant is changed Internally the instrument has a counter for each GM tube Each counter has a capacity of 16777215 counts In a gamma field the GM tubes count about 7 cps per mR h Thus in a 10 mR h field 10 minutes of counting will add about 42000 counts 10 min x 60 sec min x 7 cps mR h x 10 mR h Since this is divided by 256 before it is displayed the display will show about 164 42000 256 The total number of counts that can be displayed is 61695 Atthis time the program will accept no more counts This represents about 62 hours of counting at 10 mR h Enough to go have a long coffee break after starting the instrument Incidentally the RESET button will reset the numbers back to zero Push it any time you like It will not however change the Balance Constant Every second the counts from the gamma counter divided by 256 are multiplied by the Balance Constant and subtracted from the counts from the neutron counter divided by 256 multiplied by 100 The result positive or negative goes into the center number in the display Positive means that the Balance Constant is too low Negative means that the Balance Constant is too high Mathematically this is expressed by
8. Physics Instruments 11 Vil MASTER SETTINGS The Master Settings routine allows setting of the Fast Trip Level and the Fail Counter To enter into this routine turn the PANEL DISABLE to unlocked Push the SET UP DOWN switch up at the same time hold the DISPLAY ALARM AVERAGE TIME switch to ALARM Now turn the instrument on The display will show a single number the Fail Count in the center of the display This is the number of 15 16ths of a second that the instrument needs without a count from either GM tube before it will display FAIL Change the number by pushing on the SET UP DOWN switch Pushing the LAMPS switch will change the display to a 5 digit number which is the Fast Trip Level It starts out at 25000 and can be raised and lowered in increments of 256 by the SET UP DOWN switch To save the data J ust like the Calibrate routine turn the PANEL DISABLE switch to locked The instrument will beep to indicate that all is saved then it will resume normal operation in which case it will beep again as if it was just turned on Turning the key saves both the Fail Count and the Fast Trip Level and it can be turned at any time If it is turned while in the Fast Trip Level change section then it saves both the Fail Counts and the Fast Trip Level There is one special function in this routine When the Fast Trip Level is displayed pushing the TEST 32 will reset ALL the permanent memory to its default values The Calibration Factor Balance Con
9. about 5 seconds after which it will revert back to the radiation level The alarm level may be set at any positive integer from 1 to 400 mrem h Pushing the DISPLAY AVERAGE TIME will cause the display to read XX x 15 seconds The XX is the Average Time and it will only read 1 2 4 8 16 or 32 After the switch is pushed the display will remain for about 5 seconds after which it will revert back to the radiation level MODEL 2080 Health Physics Instruments H SET The SET switch is used in conjunction with the DISPLAY switch The SET UP or SET DOWN are used to set the Alarm Level and the Average Time It has no function when the instrument is reading the radiation level When the display shows the Average Time The DISPLAY AVERAGE TIME switch was pushed the SET UP or SET DOWN switch will cause the displayed Average Time to increase or decrease but only if PANEL DISABLE is unlocked It is necessary to hold the switch down until the desired reading is obtained The display will not roll over ateither end The display will remain on for 5 seconds after the last switch was pushed When the display shows the Alarm Level The DISPLAY ALARM switch was pushed the SET UP or SET DOWN switch will cause the displayed Alarm Level to increase of decrease but only if the PANEL DISABLE switch is unlocked If either SET switch is held down for 7 seconds the display instead of increasing or decreasing by units will increase or decrease by 10s Th
10. down the RESET and LAMPS switch and turn the instrument on 3 Setthe instrument in a 20 mR h gamma field and let the instrument count until the counts in the 1st number are greater than 300 Center the source on the sphere It should be atleast 1 meter away from the sphere 4 Using the UP DOWN switch to raise or lower the BALANCE CONSTANT 3rd number until the BALANCED NUMBER middle number is as close to 0 as possible Positive numbers are better than negative numbers 5 Tum Key to LOCK to save the values then return key to original position 2 Neutron Calibration 1 Tum the instrument off Key should be in PANEL DISABLE position 2 Hold down the RESET and LAMPS switch and turn the instrument on 3 Waitfor display to stop changing and push LAMPS The normal display will appear with the letter C to indicate calibration 4 Setthe instrument in a 100 mREM h neutron field Wait 5 minutes for the silver foil to reach equilibrium 5 Using the UP DOWN switch to raise or lower the CALIBRATION FACTOR until the instrument reading is 100 mREM h Raising the CALIBRATION FACTOR will lower the reading 6 Check it at 50 mREM h and wait 5 minutes for the silver foil to reach equilibrium Change the CALIBRATION FACTOR if necessary then recheck at 20 mrem h 7 Turn key to LOCK to save the settings and then tum instrument off 8 Ifthe CALIBRATION FACTOR was changed very much repeat the gamma and neutron calibrations MODEL 2080 Health
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12. removing two top rear screws on each side The whole top and front panel now pivot up on the two screws on the front bottom of each side The circuit board is held in place by the two screws on each side cutout on the rear panel When they are unscrewed and the connectors are removed from the circuit board the whole board slides out Underneath the board are the batteries and the power supply The batteries just slip into the holders The front panel may be detached from the read out box by removing the two screws on the lower front of each side MODEL 2080 Health Physics Instruments 16 XI CIRCUIT DESCRIPTION The instrument is divided into two distinct circuits the Head and the Read out A HEAD The signal starts at the detector tubes which put out a negative pulse that is discriminated by 01 The negative going signal is then fed to a one shot that has a pulse width of around 30 usec Q1 and Q2 are power transistors that drive the line between the head and the read out At the read out end the line goes through the LED in an optocoupler and is returned to the head This cancels the common mode signals since the instrument was designed to operate with long lines between the head and read out If they were to be longer than 100 feet the one shot should be made longer by changing R20 21 The Low voltage unregulated power is regulated by U4 to 5 volts The high voltage of 550 volts for the GM tubes is derived from a switching power supply U
13. 014 J6 4 4 40 2080 014 J1 2080 014 LS1 6 PCG 3 5 8 DIA X 8 PRPNOPRPABRPABARRERENANNNN EA SB MODEL 2080 HEADER 14 PIN MULTICOLOR Health Physics Instruments ENCLOSURE TOP ENCLOSURE BOTTOM SCREW MACHINE W LOK NUT LOCKS INT STAR PCB ASSY SPACER NYLON LOCKWASHER C SCREW MACHINE PAN PS SCREW JACK WASHER FLAT SCREW MACH PAN PH PS SHCS BLACK OXIDE THUMBSCREW KNOB SCREW LAG SCREW MACH PAN PH PS WASHER NYLON TUBE SHIELD KEYSWITCH NUTS LOCKS INT STAR CONNECTOR PC MOUNT CABLE LCD DISPLAY LCD SPACER NYLON SWITCH SWITCH SWITCH SWITCH SWITCH LED BAR RED LED BAR YEL LED BAR GRN BEZEL LED BAR BEZEL LED LED RED T 1 3 4 HOLDER FUSE FUSE 1 4 A HOLDER BATTERY TRANSFORMER CARD GUIDE CARD GUIDE CONNECTOR CABLE RIBBON 34 CND DESCRIPTION SCREW CIRCUIT BOARD ASSY CIRCUIT BOARD ASSY CONNECTOR PANEL SCREW MACH PAN PH PS CONNECTOR LOCKS INT STAR NUT CONNECTOR HORN LOUD LOCKS INT STAR CARD GUIDE MATERIAL TUBE SS WELDED HPI 2080 019 HPI 2080 019 2080 019 2080 019 2080 019 HPI 2080 019 EFJOHNSON 2080 019 2080 019 2080 019 2080 019 2080 019 2080 019 2080 019 2080 019 2080 019 2080 019 2080 019 HPI 2080 019 2080 020 2080 020 2080 020 PANDUIT 2080 020 HPI 2080 020 2080 020 2080 020 2080 020 2080 020 2080 020 2080 020 2080 020 2080 020 2080 020 2080 020 HP 2080 020 OUSER 2080 020
14. 14 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 DRAWING i 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 017 2080 017 2080 017 2080 017 2080 017 2080 017 2080 017 2080 017 2080 017 2080 018 2080 018 2080 018 2080 019 2080 019 2080 019 2080 019 2080 019 26 06 1 2080 007 07 1 2080 006 08 4 4 40x1 4 09 2 4 40 10 2 4 11 1 2080 017 12 2 341 1321 008 13 2 4 T5 2 4 40x1 2 16 2 7230 17 2 18 2 10 32 1 19A 2 3 8 24 3 4 19B 2 99 609 0 20 4 1 4 x 1 1 4 21A 4 6 32x3 8 21B 4 6 22 1 2080 022 2 3 1 2080 014 58 24 4 2 56 25 4 2 26 1 5 114 0765 24 1 2080 016 28 1 2080 014 05 29 4 341 321 008 30 1 2080 014 54 9d 1 2080 014 53 33 1 2080 014 55 34 1 2080 014 56 35 1 2080 014 57 36 1 2080 014 DS1 337 1 2080 014 52 38 1 2080 014 53 39 3 HLMP 2899 40 1 52 0002 41 1 2080 014 D12 42 1 BK HTA 43 1 2080 014 FLI 44 2 BH 3AA 45 1 2080 014 1 46 1 2080 021L 47 1 2080 021R 48 1 2080 014 32 49 1 R6006 ND DESIGN QUAN PART NO 2 56x5 8 2 56x3 16 8 32 8 6 32 3 8 6 32 3 8 4x1 4 8 32x1 2 2080 018 2080 010D 2080 008 4 40 5 8 2080
15. 171DIP 21 0 05205 71050512 71050512 81250832 81250832 71050512 710125170 101 10 241 5 16 74 4040 MC1456805E2P 74 573 27 320 45 55 116065 SCC2691AC1N24 MAX232 CPE HCPL2200 6N139 6N139 CDP1878CE 74HC139 74HC138 MC146823P LF356N 14538 LP2950 CZ 5 0 ICL7665CPA ICL7665CPA ICL7660CPA DESIGN QUAN PART NO U21 1 14584 U22 1 74 00 023 1 74 04 U24 1 74HC10 U25 1 93 46 WI 1 LL14847 X1 1 1 4 3AG 21 1 P7063 21 1 SRX1019 1 2 4 40x5 16 2 2 4 3 2 4 40 4 1 1 2 INCH 5 4 6 2 T44 7 2 RG 179B U 8 1 SF 2080 9 1 16418 T 4 4 40x5 16 2 4 4 3 4 4 40 01 1 2080 001 02 1 2080 002 03 1 2080 003 04 1 2080 005 05 1 2080 004 MODEL 2080 3 8 TOP 20TURN 1 3 8 TOP 20 TURN 1 1 TURN 2 WATT 100K X 9 1 COM 100K X 9 1 COM 100K X 9 1 COM 316L08503 10K X 5 SEPARATE 100K X 9 1 COM DIP 2A 5V 200 OHM ON OFF ON ON OFF ON PUSH BUTTON PUSH BUTTON ON OFF ON ON NONE ON KEY 110 VAC INPUT SUPERTWIST 16 X 1 5 VOLT 1024 BIT 3 6864 MHz Health Physics Instruments RESISTOR RESISTOR RESISTOR RN55D RESISTOR TRIMMER RESISTOR RN55D RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 lw CF RESISTOR 5 lw CF RESISTOR 5 lw CF RESISTOR 5 lw CF RESISTOR 5 lw CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF TRIMMER RN55D RESISTOR 5 1 4w CF RES
16. 2 contains oscillator comparator and driver FET It switches 1 on and off ata rate to keep the supply at 550 volts It measures the 550 volts through R16 and R17 D5 and act as a voltage doubler In measuring the high voltage the probe should have atleast a 100 meg input impedance A normal DVM with a 10 meg input impedance will work but it will make the head draw more power The entire head draws about 1 to 1 5 mA of current form the unregulated input when it is notin a high radiation field The 5 volts on the external connector may be used but the power drain should remain low since U4 can only supply about 100 mA of current B READ OUT The Read out is an all CMOS microprocessor based unit U2 a 6805 is the microprocessor U3 Address latch U12 U13 address decoders and U4 EPROM form the core of the support circuitry The Display U5 is connected just like a peripheral U6 is a UART that controls the serial output through the voltage translator generator of 07 014 is a peripheral interface adapter that has 24 I O lines U11 is a dual counter The signal entered the board from the head and is interfaced by the two opto couplers U9 and 010 08 the beam gate optocoupler essentially turns off the pulses from the detectors when it is active Pin 13 and 10 on U22 receive a pulse every 15 16 sec to make sure that the dual counter U11 is set properly The timing is done by the crystal 71 on U2 The frequency is divided to 900 H
17. 50 pF 1000VDC 0 01uF 1000VDC 0 01uF 1000VDC 0 005uF 1000VDC 10uF 10VDC 0 005uF 1000VDC OluF 50VDC 001uF 50VDC luF 50VDC luF 50VDC OluF 50VDC 0 01uF 50VDC 10uF 10VDC 0 luF 50VDC 0 luF 50VDC 470uF 25VDC OOOO O 6 PIN HOUSING HEADER 6 PIN D TYPE RIGHT ANGLE NPN POWER NPN POWER 10K 20 Pf 50 vdc 20 pF 50VDC 1000 uF 25 VDC 0 1 uF 50 VDC 100 uF 0 1 uF 2 2 uF 22 uF 22 uF 26 VDC Health Physics Instruments DESCRIPTION MFG CAPACITOR CERAM DISK CENTRALAB CAPACITOR CERAM DISK CENTRALAB CAPACITOR CERAM DISK CENTRALAB CAPACITOR CERAM DISK CENTRALAB CAPACITOR CERAM DISK CENTRALAB CAPACITOR TANT PANASONIC CAPACITOR CERAM DISK CENTRLAB CAPACITOR MONO NPO TRW CAPACITOR MONO NPO PANASONIC CAPACITOR MONO CERAM TRW CAPACITOR MONO CERAM TRW CAPACITOR MONO NPO TRW CAPACITOR MONO NPO TRW CAPACITOR TANT PANASONIC CAPACITOR MONO CERAM TRW CAPACITOR MONO CERAM TRW CAPACITOR ELECT RADI PANASONIC DIODE HIGH SPEED DIODE HIGH SPEED DIODE HIGH SPEED DIODE HIGH SPEED DIODE FAST REC 1KV MOTOROLA DIODE FAST REC 1KV MOTOROLA CONNECTOR 1 SIP MOLEX CONNECTOR 1 SIP MOLEX CONNECTOR PC MOUNT TEXTECHS TRANSISTOR TRANSISTOR RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1
18. G 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 24 R12 R13 R14 R15 R16 I po pa pa p p pa pa pa pa pa ja S S BS S BS S ES ID P S S p p S p p ja p pa p S S S S S o p p P1218 P1218 581 UNW104M1 581 UNW104M1 581 UNW104M1 581 UNW104M1 581UEZ103K1 551 10M10 P1218 P1218 414 414 414 mU EB B B K a GS dS CO OO ES OO N N u OO OO OO m mim pp ppp pp ppp IDS 14G TSW 114 0765 70 6 256125 IRF511 ND IRF511 ND IRF511 ND IRF511 ND IRF511 ND 10 os T USED NPP GO PEP N Z OFF F lt DESIGN QUAN PART NO R17 1 100 R18 1 1M R19 1 100 R20 1 NOT USED R21 1 1M R22 1 100 R23 1 4 7 R24 1 249K R25 1 1M R26 1 7 5 27 1 100K R28 1 10K R29 10K R30 1 20K R31 1 3K R32 1 1K MODEL 2080 22 uF 22 uF OR E ak 0 1 uF 0 1 uF 0 1 uF 0 01 uF 10 uF 22 uF 22 uF 26 VDC 26 VDC 50 VDC 50 VDC 50 VDC 50 VDC 50 VDC 50 VDC 25 VDC 25 VDC HIGH PERFORMANCE BNC ISOLATED 1 1 34 PI 1 1 34 PI D TYPE RIGHT AGLE D TYPE SOLDER CUP D TYPE 9 PI HOUSING WIRE HOUSING WIRE HEADER RIGHT ANGLE D TYPE RIGHT ANGLE QUICK RELEASE SIP SIP PNP POWER FET POWER N CHANNEL FET POWER N CHANNEL FET POWER N CHANNEL FET POWER N CHANNEL FET POWER N CHA
19. ISTOR POTENTIOM RESISTOR NETWORK MATSUSHITA RESISTOR NETWORK MATSUSHITA RESISTOR NETWORK MATSUSHITA RESISTOR NET 2 2R 50 ALLEN BRAD RESISTOR NETWORK MATSUSHITA RESISTOR NETWORK MATSUSHITA RELAY REED MAGNACRAFT SWITCH PUSH MIN PANASONIC SWITCH SPDT C amp K SWITCH SPDT C amp K SWITCH SPDT C amp K SWITCH SPDT C amp K SWITCH SPDT C amp K SWITCH SPDT C amp K SWITCH DPDT C amp K TRANSFORMER SIGNAL BINARY DIVIDER MICROPROCESSOR 8BIT MOTOROLA OCTAL LATCH 32K EPROM ATIONAL DISPLAY LCD SHELLY UART SIGNETICS RS232 DRIVER CONV AXIM OPTO COUPLER HP OPTO COUPLER HP OPTO COUPLER HP DUAL COUNTER RCA DUAL 2 4 DECODER 3 8 DECODER PERPH INTERF ADAPTER MOTOROLA OP AMP ATIONAL DUAL PREC MONOSTAB VOLT REGULATOR ATIONAL DUAL VOLT DETECTOR AXIM DUAL VOLT DETECTOR AXIM VOLT CONVERTER AXIM DESCRIPTION MFG HEX SCH TRIGGER QUAD NAND HEX INVERTER 3 INP NAND EEPROM ICT CORDSET BELDEN FUSE BUSSMAN TRANSORB MITSUBISHI CRYSTAL MICROP NYMPH SCREW MACH PAN PH PS LOCKS INT STAR NUT TUBING SHRINK TIE 3 INCH STAKE VECTOR COAX MIN 10 LONG FOIL SILVER 99 FOIL TIN 0005 KODAK SCREW MACH PAN PH PL LOCKS INT STAR LOCKS INT STAR PSEUDOSPHERE HPI HANDLE SIDE RAIL HPI HANDLE HPI COVER HEAD HPI BASE HEAD HPI 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 0
20. M tube is covered with tin This presents the same gamma attenuation as the silver The counts from each detector are scaled in two separate scalers The response from the two detectors may not be the same to gamma rays due to differences in detector volume gas pressure or shielding The two tubes must be matched within 196 mathematically The software multiplies the counts from each scaler to balance them then subtracts the gamma counts from the neutron counts to obtain Net Neutron counts It then divides this number by a calibration factor to obtain a corrected reading The resulting values because of the low counting rate need to be averaged over a period of time This is performed by the digital filter In essence it is a 16 register rotating stack that stores each new value over the oldest one adds up the stack then divides by 16 to obtain an averaged signal level The time taken for a sample is determined by the average time The alphanumeric display can display several different parameters and functions besides the radiation level In addition the microprocessor controls the outputs lamps and hom MODEL 2080 Health Physics Instruments Ill NORMAL OPERATION The instrument may be operated either from 110 VAC 60 HZ or from the internal batteries When first received the batteries may need to be charged Plug one end of the line cord into the back of the instrument and the other end into an electrical outlet The LED on the front panel ma
21. NNEL FET POWER N CHANNEL TYPE nd oe Health Physics Instruments CAPACITOR ELECTRO R PANASONIC CAPACITOR ELECTRO R PANASONIC CAPACITOR MONO CERAM TRW CAPACITOR MONO CERAM TRW CAPACITOR MONO CERAM TRW CAPACITOR MONO CERAM TRW CAPACITOR MONO CERAM TRW CAPACITOR ELECTRO RA PANASONIC CAPACITOR ELECTRO RA PANASONIC CAPACITOR ELECTRO RA PANASONIC DIODE HIGH SPEED DIODE HIGH SPEED DIODE HIGH SPEED DIODE SHOTKEY DIODE DIODE DIODE HIGH SPEED DIODE HIGH SPEED DIODE HIGH SPEED DIODE HIGH SPEED DIODE HIGH SPEED DIODE HIGH SPEED DIODE LED BAR RED HP LED BAR YEL HP LED BAR GR HP LINE FILTER CORCOM CONNECTOR PANEL AMPHENOL HEADER RA PC MOUNT CW CONNECTOR MAS TERM CW CONNECTOR PC MOUNT TEXTECHS CONNECTOR MACHINED TEXTECHS CONNECTOR METAL HOOD TEXTECHS CONNECTOR 6P SIP MOLEX CONNECTOR 2P SIP MOLEX CONNECTOR SIP 8P MOLEX CONNECTOR PC MOUNT TEXTECHS CONNECTOR CIRCULAR CANNON CONNECTOR 14P WIRE PANDUIT CONNECTOR 14 P HDR PANDUIT HORN LOUD PROJUNL TRANSISTOR TRANSISTOR INT RECT TRANSISTOR INT RECT TRANSISTOR INT RECT TRANSISTOR INT RECT TRANSISTOR INT RECT TRANSISTOR SILICONIX RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 2w CF RESISTOR 5 1 4w CF RESIS
22. OPERATIONS AND REPAIR MANUAL MODEL 2080 PULSE NEUTRON SURVEY METER September 1999 Revision 75 cce J health physics instruments 330 D South Kellogg Ave Goleta CA 93117 Tel 1 805 967 8422 II IX XI XII XIII XIV XV XVI XVII TABLE OF CONTENTS INTRODUCTION tire Uer e hs edad E RUIN 2 PRINCIPAL OF OPERATION ettet ertet eerte tet 2 NORMAL OPERATION ttti eor t hte ROS DR E oe peii T E e 3 SWITCH INDICATOR DESCRIPTIONS Sassari 5 TEST 32 5 TEST 0 5 RESET 5 LAMPS 5 PANEL DISABLE 5 POWER ON 5 DISPLAY 5 SET 6 PANEL INDICATORS 6 HORN 6 ALPHANUMERIC DIGITAL LCD DISPLAY 7 REAR PANEL DESCRIPTION idet ettet eire en eie He e edere Ae teen 7 POWER CONNECTION 7 FUSE 7 PSS 7 8 8 8 AUX I O HEAD BEAM GATE RADIATION CALIBRATION 9 A CALIBRATE MODE 9 B STORING THE CONSTANTS 10 C SAMPLE CALIBRATION 11 1 Gamma Calibration 11 2 Neutron Calibration 11 MASTER SETIPINGS aia O echec NI ed 12 FAST TRIP CALCULATIONS 12 MAINTENANCE 2 21 202 20 0 00000000000000000000000000000000000 13 INTERNAL ADJUSTMENTS AND CONTROLS 2 2220000 0 0000000000000000 15 ED EA EVER eee ae 16 CIRCUIT DESCRIPTI ON rrr nete es eren d
23. PS button The display will look like the normal display except in place of the words mrem h on the right hand side of the display will be the 3 digit Calibration Factor followed by the letter C The letter C is to remind you that you are in the calibration mode The Calibration Factor may now be set with the SET UP DOWN Switch All Switches will work like normal on the front panel except for the PANEL DISABLE switch More about itin a minute The Average Time can be changed The RESET button works like normal There are several functions that are defeated The Alarm hom will not work The overrange indicators will not work The FAST TRIP will be displayed but it is not latching These were defeated to allow testing of the FAST TRIP and to keep the ears of the calibration personnel from ringing after calibration The radiation level reading is inversely proportional to the Calibration Factor i e raising the Calibration Factor will lower the mrem h reading Once the neutron radiation level has come to equilibrium it is easy to determine the approximate Calibration Factor by multiplying the current Calibration Factor by the ratio of the current radiation level indication to the true radiation level Although the display updates once per second the radiation level needs one averaging time to completely fill the register stack with new data After getting close to the correct value itis a good idea to make small changes wait one averaging ti
24. TOR 5 1 4w CF RESISTOR 5 1 4w CF DESCRIPTION MFG RESISTOR 5 1 4w CF TRIMMER 3 8 TOP 20T RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF TRIMMER 3 8 TOP 20T RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR RN55D RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF TRIMMER 3 8 SIDE 1T RESISTOR 5 1 4w CF RESISTOR 5 1 4w CF 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 DRAWING i 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 2080 014 25 OY 4S OO Oy Oi S O U20 paa s ps ps p p pa p pa pa o ja pa jg p pa p pa s p p p p jj p pao pa 82 NOT USED NOT USED 470K 470K 10K 1 200 10K 09104 09104 09104 316L08503 06103 09104 W
25. The next group of three is the Alarm Level The last group is the status The radiation level is the same level as on the display The Average Time is the same level as on the display The Alarm Level is the same level as on the display The status consists of two bytes each represented by 2 hex digits The individual bits of each byte mean something different BIT DESCRIPTION Fault H Fault 5 rer ea umaku m Flash H2 New cycle used to flash display Overflow H overflow Debounce Hz Debounce Lamps switch Peer 012290 202 uwa T gt 4 Keep Program EEPROM Display H Display Trip Level 5 7 Display H Display Average Time Calibrate H Calibrate mode H means the bitis High ora 1 MODEL 2080 Health Physics Instruments 19 A UNDERSTANDING THE STATUS BYTES The status bytes are encoded with a normal binary code To best illustrate the process to encode the data lets assume thatthe display shows 000 200 01 00C2 Now lets concentrate on the second status byte C2 This byte can be broken down into two nibbles as they are called the C and the 2 Nibbles represent any one of 16 possible combinations of binary bits They are displayed as numbers 0 to 9 and letters A to F This notation is called HEXADECIMAL HEX The table below should clarify this It shows their equivalents BINARY 0000 0001 0010 0011 0100 0101 0110 0111 1000 1001
26. d or unprogrammed See EEPROM section for more details If the instrument is plugged into AC power the display should look like 12 0LH 7N 7G The first digit starting from the left is the switch number that was just pressed in this case the TEST 32 The next group of figures the 2 0 is the voltage that should be atthe LOGOUT 2 0 Volts The third group LH is an indication of both the AC Power detector and the Low battery detector The two last groups 7N and 7G are the counts from each GM tube Most switches do double duty The action of the switches in order is included in the table below NM mme SET UP Turns on Green Light SET DN Turns on Yellow Light ccm T zo 00007 pum p p _ mq qme You will notice that the switches follow a sequence around the panel starting at the upper left hand corner and proceeding across the top row and then across the lower row The LOGOUT Voltage also follows a pattern RESET sets it for 0 mrem h or 4 1 2 Volts TEST 32 sets it as for 32 mrem h or 2 0V Lamps takes it to 3 2 Volts These are used in adjusting the offset and gain trimmers inside the instrument The RMP stands for RAMPING The voltage slowly ramps between 1 2 and 5 Volts At 5 Volts it starts over again at 1 2 Volts The Lamps and Hom are actuated by the switches shown in the table above This is to test them They are tumed off by RESET MODEL 2080 Health Ph
27. d off if this happens F BEAM GATE This is an electrically isolated connector that will turn off the counts from the detector when a positive signal is applied to the beam gate The connector is isolated from ground MODEL 2080 Health Physics Instruments VI RADIATION CALIBRATION The instrument has a special routine for radiation calibration that facilitates balancing the two tubes as well as setting the absolute radiation level The instrument does not have to be opened to calibrate it and the calibration is done using the front panel controls The calibration is completely digital A CALIBRATE MODE To enter the calibrate mode make sure the instrument is unlocked Hold down the RESET Switch and the LAMPS switch Now tum the instrument on The word CAL will appear to tell you that you are in the calibrate mode The display will then show three numbers This is the balance section of the calibrate routine The idea is to balance the counts from the two GM tubes Starting from the left the first number is the counts from the neutron GM tube divided by 256 If the left hand display reads 26 then it means that the internal counter for the neutron GM tube has accumulated 256 times 26 or 6656 counts The next number is the balance It is either positive or negative If there are too many gamma counts then the number goes negative if there are too many neutron counts then the number goes positive The next and last number is the Balance
28. ed Longer cables can be used but will require a minor component value change Please consult the factory MODEL 2080 Health Physics Instruments 22 C PSS CONNECTOR The PSS Connector is a Burndy 6 Pin Twist Lock connector There are 2 sets of contacts Contact set 1 and contact set 2 They are usually wired in series If one set should stick closed the other set can still open the circuit 007 LLL C LLL Teme C MODEL 2080 Health Physics Instruments 23 DESIGN QUAN XVI PART LIST DRAWING i col C02 C03 C04 cos C06 C07 C08 C09 C10 217 C12 C 13 C14 15 C16 C17 1 2 D3 o Hp RIO P pp ppp pp ppp ppp pppp 551 10M10 DD 5022 581 UEZ103K1 581 UEC102J1 581 UNW104M1 581 UNW104M1 581 UEZ103K1 581 UEZ103K1 551 10M10 581 0 104 1 581 0 104 1 1224 1N4148 1N4148 1N4148 1N4148 MR818 MR818 22 01 3067 22 01 2062 409F ND 4921 4921 3M 30K N Q C0 WWD N 400 1 2 7 10K 10K 5 1K 3K M8149 LM393N MAX630CPA 14528 LP2950CZ 5 0 713 72 3 P50AA 21RD722 21RD722 P1225 581 UNW104M1 DESIGN QUAN PART NO C05 1 P1221 C06 1 P1221 C07 1 581 UNW104M1 C08 1 551 2 2 16 C09 1 P1218 26 VDC C10 1 P1218 MODEL 2080 50 pF 1000VDC
29. ed on the horn will beep if all is OK This is a loud beep If the volume control is turned up then a soft beep will also be heard as soon as the instrument is turned on followed by the All OK beep When the Alarm Level is exceeded the horn will also turn on continuously at full volume and is not affected by the setting of the volume control MODEL 2080 Health Physics Instruments K ALPHANUMERIC DIGITAL LCD DISPLAY In normal operation there are four possible displays They are DISPLAY COMMENT xxx mrem h Radiation level FAIL GM tube failure FAST TRIP Fast Trip Level exceeded The first display is the normal display of the radiation level The leading zeros are blanked The second display is the overrange indicator This will be displayed if the radiation level exceeds 400 mrem h but does not exceed the Fast Trip Level If the radiation level falls below 400 mrem h the display will revert to the normal radiation level display If either GM tube fails to produce a pulse during a predetermined time period the display panel shows FAIL This is notlatching and resumption of pulses will cause the display to revert to the radiation level If the Net Neutron count rate exceeds the Fast Trip Level during any 15 16 second counting period FAST TRIP will be displayed See section XIV PSS for a complete description of PS V REAR PANEL DESCRIPTION The rear panel has several plugs and a fuse All connections to the instrument are made here
30. ee yah 17 A HEAD 17 B READ OUT 17 SERIAT OUTBU E SS erede ma Sau S EE E E coke Se 19 A UNDERSTANDING THE STATUS BYTES 20 Tm PERSONAL SAFETY SYSTEM 58 21 REAR PANEL 5 5 22 A CONNECTOR PINOUT 22 B HEAD CONNECTOR 22 C PSS CONNECTOR 23 PART EIST oett eere a t a EE ee te lets 24 SCHEMATICS o ne 28 MODEL 2080 Health Physics Instruments l INTRODUCTION The Model 2080 Pulse Neutron Survey Meter is designed to measure either pulsed or steady state neutron fields The instrument may be operated either as a fixed monitor plugged into the wall or portable with the internal batteries The instrument displays the dose rate on a digital alphanumeric LCD display The microprocessor based instrument incorporates many additional features to make it both easy to use and easy to maintain and calibrate I PRINCIPAL OF OPERATION The instrument uses the principal of nuclear capture to detect the neutrons A 25 cm diameter polyethylene pseudosphere moderator thermalizes the neutrons They are then captured by silver foil The resulting beta activity is proportional to the previously acquired neutron dose The betas are detected by a GM tube that is wrapped with the silver foil Since the GM tube is also sensitive to external radiation not from the silver foil a second GM tube is used to cancel out any background radiation The second G
31. ing current of the batteries to about 26 mA which is their high end trickle charge rate Q1 turns the system on and off U18 detects the voltage that is present and if itis high enough it saturates Q1 and turns on the power If the battery voltage or the line voltage fall too low then U18 will turn off Q1 and the instrument will appear dead This prevents reverse discharge of the batteries and also prevents the display from reading an incorrect reading since when Q1 turns off the display will go blank The other half of U18 is the low battery detector that checks the condition of the input voltage to flag the system to display low battery 019 detects both the fact that AC power is present by measuring the voltage from the secondary of T1 through D7 and filter C7 R23 D8 and R25 and also generates a reset signal for the system if 5 volts falls too low U17 is a 3 terminal voltage regulator which drops the input voltage to 5 volts U20 is a voltage converter that converts 5 to 5 for the display and the op amp 015 The reset switch S1 resets the system just like a power on The entire system operating off of batteries with the lights off needs about 26 mA at 11 VDC MODEL 2080 Health Physics Instruments 18 XII SERIAL OUTPUT The serial output at 9600 baud consists of several groups of digits On a terminal the output should look like 000 01 200 0001 The first group of three is the radiation level The next group of two is the Average Time
32. is setting does not roll over at either end The Alarm Level and the Average Time are remembered even when the power is tumed off and the batteries are removed The instrument stores these values when the display reverts back to the normal radiation level Consequently if you change either one then turn the power off before going back to a normal display the instrument will not store the new value I PANEL INDICATORS AC POWER indicator indicates that the instrument is plugged into the line and that the batteries are charging GREEN YELLOW and RED Bar Lights indicate the radiation level In normal operation one ofthese lights flashes according to the following GREEN 0 2 mrem h YELLOW 3 to 19 mrem h RED above 20 mrem h All three flash when the Alarm Level is exceeded The LAMPS switch will tum these indicators on and off if the instrument is on batteries and the PANEL DISABLE is unlocked When the instrument is on and operating from AC power the lamps will function normally and cannot be turned off using the LAMPS switch The lamps are off when the instrument is switched to battery operation J HORN The hom is used to indicate the status of the counts from the neutron GM tube the Alarm and various beeps from the program The hom volume control changes only the loudness of the beep from the neutron GM tube Turn it up and the horn will beep every time a count is detected from the neutron GM tube When the instrument is first turn
33. me then make another small change until the instrument reads properly B STORING THE CONSTANTS Up to this point the Balance Constant and the Calibration Factor have been changed but they are only in volatile memory If you turn the power off now the new balance and calibration numbers revert back to the old numbers To make them permanent you only need to turn the PANEL DISABLE back to lock and wait for the beep instrument will resume operation just like it was turned on and beep again to indicate all is well To change the calibration data again itis necessary to enter the calibration mode again The data be saved at any time in the course of calibration The instrument can be balanced one day then calibrated the next It is easy to review the settings of the MODEL 2080 Health Physics Instruments 10 Balance and Calibration by just entering the calibration mode looking atthe values then turning the instrument off Unless the key is turned the values will not be changed If the key is turned and the values were not changed the old values will be re saved in memory and will therefore not be changed C SAMPLE CALIBRATION The Model 2080 needs both a gamma calibration and a neutron calibration The gamma calibration is before the neutron calibration Set the time constant to 8 x 15 or higher for a more accurate calibration 1 Gamma Calibration l Tum the instrument off Key should be in PANEL DISABLE position 2 Hold
34. nt adjusts the voltage at which the instrument automatically turns off even if the on off switch is on This keeps the instrument from reverse biasing the batteries resulting in their catastrophic failure Use the same connection as for the low battery check except change the external power supply to 6 5 volts Now turn the Power Fail trimmer until the instrument just turns on CCW will tum it on and CW will turn it off X SERVICE Servicing the instrument should be relatively easy since the instrument is designed in a plug together modular fashion The head and read out are two separate items and the plug in detector tubes are a third To gain access to the instrument the read out box may be removed from the handle and sphere by removing the thumbscrews Two washers between the read out and the handle will fall out Keep them and put them back when reassembling the instrument They keep the handles from scratching the case The detector box has 4 screws two on each side The cover lifts off Inside is the high voltage power supply and discriminators as well as the detector paddle The detector paddle unplugs from the board and the paddle removes by just pulling it upward The circuit board is held in the instrument by two screws through the board and the two screws holding the connector to the rear of the case The stainless tube will have to be removed before the board can be slipped out it just pulls out The read out box can be opened by
35. operation The jumper can be removed from the instrument or it can be stored by pushing it over only one pin The four screwdriver adjustments are factory set however they may be changed or checked depending on the use of the instrument The two adjustments next to the contrast control set the voltage gain and offset for the LOGOUT signal on the PSS connector and the AUX I O connector To set them put instrument into the maintenance mode and monitor the LOGOUT voltage Push RESET on the front panel Adjust the offset so the LOGOUT reads 1 2 Volts Depress LAMPS on the front panel MODEL 2080 Health Physics Instruments 15 and adjust the gain so the LOGOUT reads 3 2 It will be necessary to repeat the sequence of the two adjustments because they interact somewhat To check the intermediate voltage values see the MAINTENANCE FUNCTION for a complete description of the LOGOUT test voltages The other two adjustments are the low battery and power fail detector The low battery adjustment is made by replacing the batteries with a power supply and operating the instrument without the line cord Enter the maintenance mode Turn the voltage that replaces the batteries to 7 2 Volts Adjustthe low battery adjustment until the low battery indicator in the display changes from L to H orH to L This is an abrupt change without hysteresis About 1 4 tum will change the display CCW turns the display to H and CW turns it to L The Power Fail adjustme
36. rked AC POWER should light This indicates that the instrument is plugged into the wall The batteries take about 30 hours to fully charge The instrument may be operated on either power source without reservation If the batteries are too low for proper operation the instrument will not turn on If the instrument does turn on and the batteries are low the display will flash LOW BATT to indicate that the batteries are low The whole read out box tilts up or down for best viewing angle It is secured in position by the two thumbscrews on the sides Tum the instrument on The hom will beep to indicate that the instrument is functioning properly and the display will show XXX mrem h The XXX is the radiation level and will indicate the level from 1 to 400 mrem h If the radiation was above 400 mrem h the display will show gt 400 mrem h The value shown on the display represents the average of 16 consecutive readings This is done to smooth out the fluctuations in the display The time between readings is determined by the Average Time The Average Time can be seen by pushing the DISPLAY AVERAGE TIME button The display will now show 15 seconds the X representing either 1 2 4 8 16 or 32 There are two ways of thinking of this number One way is that the total time for a new reading is X x 15 seconds just like the display says This means that if the Average Time is set to 8 the time for a complete new reading would be 8 times 15 second
37. s or 120 seconds or 2 minutes The other way of thinking has to do with update time The update time is the time between readings and is the Average Time times 15 16 seconds When the Average Time is 1 the display will update every 15 16 seconds When it is on 8 it will update every 8 time 15 16 second or 7 5 seconds No matter where the Average Time is set it stil takes 16 updates to replace the running average for the display but the display will change every Average Time times 15 16 second If the PANEL DISABLE switch is not in the locked position then the Average Time may be changed by pushing the SET switch either up or down The DISPLAY switch also shows the Alarm Level The Alarm Level may be set anywhere from 0 to 400 mrem h When the Alarm Level is matched or exceeded the horn tums on If the instrument is plugged into the wall or the lamps are tumed on for battery operation then the three colored lamps will flash This alarm is self resetting and will not latch When the level falls below the Alarm Level the alarms will turn off The RESET switch on the front panel resets the instrument to zero It may be pushed at any time Itis locked out of operation by the PANEL DISABLE switch The LAMPS switch turns on the lamps if the instrument is on batteries and the PANEL DISABLE switch is notlocked Push it once to turn on the lamps Push it again to turn MODEL 2080 Health Physics Instruments them off The battery life is greatly reduced wi
38. s to the adjustments and the inside of the case remove the two screws located on the sides at top back of the instrument The whole front panel and top which are one piece rotate up and forward pivoting on the lower front There is a small reset push button on the left hand side of the circuit board This resets the microprocessor whenever it is pushed i e a warm boot If it is pushed it does the same thing as when the power is removed then re applied Dont hesitate to push it POWER FAIL LOW BATTERY MAINTENANCE JUMPER RESET lt DISPLAY h CONTRAST LOGOUT GAIN LOGOUT OFFSET Figure 2 Internal Controls On the right rear of the circuit board there is also a set of pins with a jumper pushed on one of them This is the only internal adjustment to the microprocessor It makes the instrument go into the maintenance mode immediately at turn on No switches need be pushed to do it and its purpose is for testing when all else fails To try it put the jumper on the two rear terminals and turn the instrument on it should be in maintenance mode When the jumper is removed the instrument is in its normal mode
39. stant Fast Trip Level and Fail Count will be reset Itis included to program a new memory chip to the default values or to start everything out fresh if a problem occurs A FAST TRIP CALCULATIONS The value in the Fast Trip Level is calculated every 15 16 seconds It is independent of the setting of the Average Time Every 15 16 seconds it compares the Net Neutron counts for that 15 16 seconds to the Fast Trip Level If the Net Neutron counts are higher than the Fast Trip Level it goes into FAST TRIP The Net Neutron counts are related to the mrem h by the following Fast Trip Number 50 mrem h Cal Factor 100 To trip at 500 mrem h therefore set Fast Trip Level to 50 500 100 100 25000 This assumes that the Calibration Factor is 100 The default value for the Calibration Constant is 100 The default value for the Fast Trip Level is 25000 MODEL 2080 Health Physics Instruments 12 VIII MAINTENANCE FUNCTION The maintenance function is built into the instrument to facilitate checking out the instrument Like the other secondary functions this is entered by turning the instrument on while a switch is depressed In this case the switch is the TEST 32 switch To get into the maintenance function turn the PANEL DISABLE to unlock and hold down the TEST 32 switch Turn the instrument on Immediately you will see the display with many numbers and letters If the instrument displays FAIL then the EEPROM is either defective not installe
40. th the lamps on and for this reason they cannot be left on if the PANEL DISABLE switch is locked If the AC power is removed and the instrument is tumed on the lamps will be turned off In addition to the standard Alarm Level which is based on the radiation level displayed there is another internal alarm level which is based on the rate of radiation received every 15 16 seconds If this internal level that is set about 500 mrem h is exceeded then the instrument will show FAST TRIP in the display This is a latching alarm and once tripped can only be turned off by either turning the instrument off then back on or by pushing RESET The instrument will then resume normal operation The instrument checks the status of the detectors and if it detects that one is not working properly it shows FAIL on the display FAIL is self resetting 32 LOCK 0 TEST RESET LAMPS PANEL DISABLE ON AC SET DISPLAY VOLUME POWER UP ALARM O AVERAGE C DOWN TIME FUSE 110VAC 60 HZ O oC Joo Jo GATE PSS AUX I O HEAD Figure 1 Front and Rear Panels MODEL 2080 Health Physics Instruments IV SWITCH INDICATOR DESCRIPTIONS The front panel switches control the operation of the instrument There are no rear panel switches They are described in order the top row from left
41. the other way around The display changes at units with no rounding off mRem h METER DISPLAY VOLTS E dm dq Note FAST TRIP may occur atthis point depending on its setting XIV Personal Safety System PSS The Personal Safety System is designed to make the instrument useful as an area monitor The system is self checking and will activate only under the following conditions 1 Power is on 2 Unitis connected to AC power 3 Unitis not alarming 4 Unitis notin FAST TRIP 5 Unit has not detected a failure 6 PANEL DISABLE is locked MODEL 2080 Health Physics Instruments 21 7 Instrument is working properly Any one condition will cause the instrument to cancel PSS Item 7 will cause the instrument to release PSS in 5 seconds All the others will cause itto release in less than 1 second XV REAR PANEL CONNECTORS CABLES A CONNECTOR PINOUT BECTON LN RS 232 10V LOGOUT LOGOUT GAMMA OUT B HEAD CONNECTOR The Head connector is for the cable between the head and the read out unit The Cable that is used should be similar to BELDEN 9503 This cable has 3 twisted pairs each pair in a bedfoil shield No other cable is recommended The connections to each end of the DB 9 connector are the same The connections are Red and Black 5 Black pair White and Black White 2 Black 7 pair Green and Black Green 1 Black pair Cables up to 100 feet are allow
42. to right then the bottom row from left to right A TEST 32 Simulates 32 mrem h atthe GM tubes The display will increment to 32 mrem h after the Average Time This test does not interfere with the routine to check for detector failure Holding in TEST 32 will notlead to a FAIL indication B TESTO Simulates no counts from the GM tubes FAIL will occur in the number of update Cycles programmed in to FAIL COUNT e g after 60 seconds See SECTION VII MASTER SETTINGS C RESET Resets the stack and resets the Average Time If the Average Time was set to 32 and the RESET was pushed the time for the next update would be 32 15 16th seconds or 30 seconds Will not work if the PANEL DISABLE is locked D LAMPS Turns on or off the front panel indicator lamps if the instrument is on batteries and the PANEL DISABLE is unlocked E PANEL DISABLE The PANEL DISABLE switch needs a key to operate When itis in the locked position the RESET LAMPS and SET UP and DOWN switches will not function When it is in the Unlocked position all front panel switches function F POWER ON This tums on the power to the instrument G DISPLAY This switch changes the display from mrem h to the Alarm Level or to the Average Time setting The radiation level is the normal display Pushing the DISPLAY ALARM will change the display to read XXX mrem h Alarm The XXX is the Alarm Level setting After the switch is pushed the display will remain for
43. ysics Instruments The PSS Relay is actuated by the LAMPS switch Push it and the circuit is closed After about 5 seconds the contacts will open This checks the watchdog timer that checks for Microprocessor failure If the LAMPS switch is pushed then the RESET switch the relay should fall out immediately This is the normal course of actuation by the computer when it senses that PSS is not allowed The two H or L indicators show the status of the AC Power and the Low Battery detector The table shows their indicators AC Power Lis AC Connected H AC not connected LOW BATT L is low Battery H is good battery On battery power they normally read HH on AC Power they would normally read LH The Last groups are the GM counters The two letters next to the digits correspond to N for neutron and G for gamma The counters count down from 7 to 0 then return to 7 They give an indication of the GM tubes counting They start at 7 when the maintenance mode is entered The maintenance mode also exercises the RS 232 It puts out HI continuously at 9600 baud MODEL 2080 Health Physics Instruments 14 IX INTERNAL ADJUSTMENTS and CONTROLS There are only 5 internal adjustments and they are all located on the circuit board in the read out box 4 of the 5 are screwdriver adjustments The 5th is the display contrast It can be rotated by the finger and is in the right hand corner of the circuit board if the display is facing away from you To gain acces
44. z by U1 for the Timer input to the microprocessor This is the signal used to time the whole instrument The EEPROM U25 is attached to the microprocessor If A new chip is installed it is necessary to program it See the MAINTENANCE SECTION The analog output LOGOUT is generated by RN4 connected to 014 the PIA It is an R 2R network Its output is level shifted by U15 to a negative output MODEL 2080 Health Physics Instruments 17 The Lamps and Horn signals are also generated by U14 and buffered for more current by the VFETS Q2 3 4 and 5 The PSS system contains U16B a retriggerable one shot which acts as a watchdog timer Every 15 16 seconds the output of U14 PC7 pin 35 pulses This keeps U16 triggered if its reset pin U16B p 13 is notactivated If the system quits and there are no more pulses then U16B will time out in about 5 seconds and turn off the PSS relay RY1 The system can also turn off PSS by activating the reset line on U16B which is its normal way of turning off PSS The signal from U14 PC7 Pin 35 represents the heartbeat of the system One shot U16A stretches the pulses from the GM tubes enough to be heard on the horn The power supply is powered by both batteries and the line T1 is connected to the line filer and consequently to the line Z1 is a power conditioner that keeps voltage transients out of the system The power from T1 is rectified and combined with the signal from the batteries through D4 R13 sets the charg
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