VELA ISL4 Physics EPROM manual
Contents
1. ISL4 ISL4 EPROM s User NOTES PROGRAM 72 PHASE METER PARAMETER VALUES NONE USED CLEARS THE DISPLAY THE PROGRAM COMPARES THE PHASE OF TWO SIGNALS APPLIED TO CHANNEL 1 AND CHANNEL 2 INPUTS THE RESULT IS DISPLAYED IN DEGREES IN THE RANGE O TO 359 A PHASE SHIFT OF 360 DEGREES BEING RESET TO ZERO A RESULT OF 90 DEGREES MEANS THAT CHANNEL 2 INPUT IS A QUARTER OSCILLATION BEHIND CHANNEL 1 THE WAVEFORM MUST CROSS ZERO VOLTS THE 7 5 DISPLAY REFRESHES EVERY 1 SECONDS BUT REMAINS BLANK IF NO INPUT IS DETECTED RESOLUTION 1 DEGREE UP TO 100 Hz DETERIORATING TO 10 DEGREES v 1kHz MINIMUM FREQUENCY v 2Hz camer Ger 2S CAPACITOR EXAMPLE 1 50 Hz v To cuewwtL 2 250 mV Source i SHUNT CHANNEL 1 MEASURES VOLTAGE CH2 MEASURES CURRENT SEE APPENDIX A A SHUNT OF lmA IS SUITABLE AND VELA INDICATES THE PHASE LAG OF CURRENT COMPARED TO VOLTAGE i e 270 DEGREES EQUIVALENT TO CURRENT LEADING VOLTAGE BY 90 DEGREES USE OF A TWIN BEAM OSCILLOSCOPE PROVIDES VISUAL SUPPORT FOR THE MEASUREMENT 122 x ISL4 ISL4 EPROM s User Notes CASE STUDY MEASUREMENT OF WAVELENGTH OF SOUND ee ENT oUUND LOUDSPEAKER SIGNAL MICROPHONE PLACE THE MICROPHONE NEXT TO THE LOUDSPEAKER THEN MOVE IT AWAY UNTIL A POSITION OF ZERO PHASE SHIFT BETWEEN THE LOUD SPEAKER SIGNAL AND THE MICROPHONE SIGNAL IS FOUND BEWARE OF DOPPLER EFFECTS CONTINUE MOVING THE LOUDSPEAKER2. 2 INSTRUMENTATION SOFTWARE LTO ANA SOFT Xe rare lt S gt t3 2 355 4 3 dm ANSUFILISNI USER 7 MANUAL FOR PHYSICS EPROM D A BINNEY CLARKE 1985 Printed in England by W 5 Maney amp Son Ltd Leeds ERRATA Prog 65 p 13 If unscreened leads up to 4 metres long are connected to the input with the range set to 250mV as described then mains pickup may be excessive and the mains period of 0 0200s will be measured This can usually be overcome by connecting the negative side of VELA to earth Do not connect to the negative of the power supply and blow up your VELA Progs 63 and 64 Appendix A p 38 This method is not recommended as it results in the current being measured twice Ix with school meter and lx with VELA and produces wiring of unnecessary complexity It does work for shunts up to but gives false results if a 10 shunt is used as the shunt resistance is small enough 0 012 for contact resistance to become important Use of the plug on unit described opposite is strongly recommended USER MANUAL FOR PHYSICS EPROM INSTRUMENTATION SOFTWARE LTD 7 GLEDHOW WOOD AVENUE ROUNDHAY LEEDS 158 1NY 10532 662505 ISL4 ISL4 EPROM s User Notes INTRODUCTION The programs available on ISL4 ISL4 are primarily aimed at the secondary school physics teacher They were created by Dav
3. MAKES IT IDEAL FOR HIGH SPEED MEASUREMENT SUCH AS THE SPEED OF AN AIR RIFLE PELLET typically 120 mhec foi 2 SCHEMATIC DIAGRAM 5 volts INPUT RED GROWND RETIN amp uAcc TERMWAL USE KEYPRESS SEQUENCE 3 E AS VELA MK I IS NOT FITTED SEPARATE POWER SUPPLY MUST TIMING DIAGRAM Nise 19 volts 15 Foi e roi BROKEN BROKEN WITH A 5V OUTPUT A BE USED MAKE SURE A SUITABLE RECEPTACLE IS USED TO CATCH THE PELLETS A THICK METAL WASTE BIN WITH A WOODEN BASE MIGHT BE USED WITH A SHEET OF CARD OR POLYSTYRENE TO PREVENT RICOCHETS E ISL4 ISL4 EPROM s PROGRAMS 167 68 and PREAMBLE EXPERIMENTAL SUGGESTIONS A LTERWATIVELY LIGHT REAM j ACLELERATING User NOTES 169 ACCELERATION MEASUREMENTS THE AIM IN WRITING THESE THREE PROGRAMS WAS TO EXTEND THE METHODS AVAILABLE TO THE PHYSICIST FOR MEASURING ACCELERATION AS THE TIMINGS ARE DONE WITH 100 RESOLUTION TIMER GOOD RESULTS CAN BE OBTAINED USING SHORT LENGTHS OF CARD etc TO CUT THE LIGHT BEAMS ALTHOUGH IT WAS CONSIDERED ADVANTAGEOUS TO BE ABLE TO OBTAIN A DIRECT READING OF ACCELERATION FOR INSTANCE WHEN ILLUSTRATING FORCE AND ACCELERATION IT WAS RECOGNIZED THAT MANY TEACHERS MAY WELL BE UNHAPPY WITH SUCH A BLACK BOX APPROACH PREPARATORY WORK WITH PROGRAMS 167 AND OR 68 SHOULD MAKE THE METHODOLOGY OF THE ACCE
4. N O 10 12 13 14 15 16 17 18 19 20 21 22 23 24 26 27 28 29 30 32 34 36 37 38 40 42 ISL4 ISL4 EPROM s User Notes INSERTION OF ISL4 IN VELA MK 11 AFTER REMOVAL OF POWER PROCEDURE 1 UNSCREW THE FOUR RUBBER FEET SUPPORTING VELA 2 LIFT OFF THE BASE PLATE TO GAIN ACCESS TO THE PRINTED CIRCUIT BOARD 3 LOCATE THE SPARE EPROM SOCKET IC 23 INTO WHICH 4 5 6 7 THE NEW EPROM IS TO BE INSERTED THE POSITION OF THIS SOCKET IS INDICATED BELOW PLACE THE EPROM ISL4 ONTO THE SOCKET IC 23 AND CHECK THAT THE INDENTATION IN THE PLASTIC BODY OF THE CHIP IS POINTING THE SAME WAY AS FOR 1511 IF THE LEGS OF THE EPROM ARE TOO WIDE REST THE EPROM ON ITS SIDE ON A FLAT SURFACE AND CAREFULLY BEND THE LEGS SLIGHTLY INWARDS PRESS DOWN FIRMLY ON THE SECOND EPROM SO THAT THE LEGS ARE HELD BY THE SOCKET FIND IT USEFUL TO PRESS DOWN WITH MY THUMBS WHILST PUTTING A FINGER UNDERNEATH THE PCB IN ORDER TO BOTH SUPPORT THE PCB A LITTLE AND PROVIDE REACTION TO THE THUMBS DO A QUICK VISUAL CHECK THAT THE EPROM IS IN THE CORRECT WAY ROUND AND THAT ALL OF THE EPROM LEGS ARE HELD IN THE SOCKET IF YOU NEED TO REMOVE EPROM s USE A SMALL SCREWDRIVER TO GENTLY PRISE THE EPROM AWAY FROM THE SOCKET j REFIT THE BASE PLATE AND THE FEET LOCATION oF OUR LocAnon OVR 1 OTTES GRAPHICS EPROM ISL2 ISL3 1 ISL4 ISL4 EPROM s Program Number 60 61 62
5. 63 64 65 66 67 68 69 71 72 73t 74 75 76 77 78 79 Description Digital Voltmeter DVM DEC PT ADJUST DVM DEC PT OFFSET ADJUST DVM OFFSET ADJUST PLUS SCALING ENERGY METER POWER METER 100 us TIMER SPEED MEASUREMENT TRIPLE 100 TIMER DUAL SPEED PLUS SINGLE TIMER ACCELERATION DIGITAL THERMOMETER CAPACITANCE METER PHASE METER TEMPERATURE DATALOGGER RATEMETER MOMENTUM TIMER MOMENTUM TIME AND SPEED MOMENTUM TIME AND SPEED VARIABLE SQUARE WAVE GENERATOR VARIABLE SINEWAVE OSCILLATOR AN ADD ON MODULE IS ALSO REQUIRED SEE APPENDIX Finally good luck with these programs routines make VELA even more flexible to use in the science laboratories and that they will encourage other teachers to develop their own software It takes a special talent and level of commitment to grams but if you have only one routine ISL will be interested to ut it Code pro hear abo sER NOTES Parameter DETERMINES OFFSET TWO PARAMETERS lst DETERMINES OFFSET 2nd DETERMINES SCALING SELECTS PULSE SHAPE AS FOR PROGRAM 05 TWO PARAMETERS Ist SELECTS PULSE SHAPE 2nd IS THE DISTANCE BEING TIMED SELECTS PULSE SHAPE TWO PARAMETERS lst SELECTS PULSE SHAPE 2nd IS THE DISTANCE BEING TIMED 0 SELECTS RANGE 50 pF TO 0 2 uF I SELECTS RANGE 0 1uF TO 1000 UF DETERMINES n SECS BETWEEN SAMPLES DETERMINES n SECS 255 MAX OVER WHICH AVERAGE
6. IN THE POWER LEAD 3 1514 1814 EPROM s User Notes PROGRAM 160 A DIGITAL VOLTMETER WITH MOVABLE DECIMAL POINT PARAMETER VALUES NONE USED THE VOLTAGE FOR A CERTAIN CHANNEL IS DISPLAYED AS FOR DVM PROGRAM 00 DECIMAL POINT RESELECT CAUSES THE DECIMAL POINT TO FLASH ADJUST P MOVES THE DECIMAL POINT LEFT OR RIGHT RESPECTIVELY ENTER RETAINS THE PRESENT POSITION OF THE DECIMAL POINT e EXAMPLE 1 I VELA USERS CAN DISPLAY THE ACTUAL VOLTAGE BEING MEASURED WHEN THE RANGE SWITCH IS IN THE 250 mV POSITION BY THE KEYPRESS SEQUENCE s 0 n cc EXAMPLE 2 IF YOU PUT A WIREWOUND RESISTOR SAY 10 Ohm ACROSS THE CHANNEL 2 INPUT TERMINALS IN ORDER TO MEASURE THE CURRENT i THROUGH A CIRCUIT SELECT I THE 250 RANGE FOR CHANNEL 2 AND DISPLAY THE CURRENT IN AMPS BY THE KEYPRESS SEQUENCE D fe de CURRENT VALUES UP TO 0 0250 AMPS WILL BE DISPLAYED ISL4 ISL4 s PROGRAM 61 PARAMETER VALUES KEY IN EXAMPLE USEFUL SUGGESTION DECIMAL POINT ADJUST User NOTES DIGITAL VOLTMETER WITH MOVABLE DECIMAL POINT AND OFFSET THE PARAMETER VALUE DETERMINES THE SIZE OF THE SET IN THE RANGE 0 TO 999 THE OFFSET IS ADDED TO THE VOLTAGE MEASURED AT ALL FOUR INPUTS WHEN CALCULATING THE OFFSET IGNORE THE DECIMAL POINT PROGRAM NUMBER N N OFFSET THE DISPLAY SHOWS THE SELECTE
7. PARAMETER VALUES 1 i PARAMETER 2 KEY IN User NOTES DIRECT ACCELERATION MEASUREMENT TWO PARAMETERS ARE USED DEFINES THE TRIGGERING EDGES AS IN PROGRAM 05 o UL at es sta x su du EE NUMBER IN THE RANGE 1 TO 999 IS THE DISTANCE INVOLVED e g LENGTH OF INTERRUPT CARD OR DISTANCE BETWEEN DETECTORS SEE APPENDIX B FOR SUGGESTED ARRANGEMENTS DISTANCES IN mm GIVE ACCELERATION IN mm s DISTANCES IN m GIVE ACCELERATION IN m s ENTER TRIGGERING SELECTION Iv n LENGTH BEING TIMED THE DISPLAY CLEARS APART FROM THE PROGRAM NUMBER START CLEARS THE DISPLAY READY FOR TIMING PULSES SHOULD BE INPUT DIRECT TO THE PULSE INPUT VIA THE CHANNEL 1 AMPLIFIER WITH THE EXTERNAL INTERNAL SWITCH SET TO INTERNAL PROGRAM NUMBER WHEN ALL THREE TIMINGS ARE COMPLETE THE ACCELERATION IS DISPLAYED TO CARRY OUT FURTHER MEASUREMENTS PRESS START ISL4 ISL4 EPROM s PROGRAM 70 ESSENTIAL EQUIPMENT PARAMETER VALUES KEY IN UNDER OVER RANGE CELSIUS KELVIN CHANNEL CHANGE EXAMPLE User NOTES DIGITAL THERMOMETER THE VELA TEMPERATURE MODULE MUST BE CONNECTED TO THE I O PORT SEE APPENDIX C NONE USED 7 0 AND THE TEMPERATURE BEING SENSED ON CHANNEL 1 15 DISPLAYED IN DEGREES CELSIUS THE DISPLAY REFRESHES EVERY SEC APPROX IF NO SENSOR IS CONNECTED TO CHANNEL 1 OR IF THE TEMPERATURE IS 25 OR LOWER THEN 1
8. kt gt _ Looe ll START SToP d THIS IS THE LENGTH OVER WHICH TIMING TAKES PLACE AND ALLOWS VELA TO CALCULATE THE SPEED DIRECTLY IF THE LENGTH OF THE CARD IS MEASURED IN MILLIMETRES THEN THE SPEED WILL BE IN mm s 6 PROGRAM NUMBER ENTER TRIGGER SELECTION PULSES FROM THE LIGHT BEAMS SHOULD BE INPUT TO 1 INPUT AND CH 2 INPUT INITIALLY THE DISPLAY INDICATES WHETHER CH 1 INPUT IS LO W OR HI GH KEYPRESS CAUSES THE DISPLAY TO INDICATE WHETHER CH 2 INPUT IS LO W OR HI GH e g CURRENTLY LOW BOTH CH 1 INPUT AND CH 2 INPUT ARE PROGRAMMED TO BEHAVE AS SCHMITT TRIGGER INPUTS TO IMPROVE PERFORMANCE RELIABILITY PRESS START THE DISPLAY CHANGES LENGTH OF CARD ISL4 ISL4 EPROM s User NOTES PROGRAM 76 DUAL SPEED continued NO RESULTS ON CH 2 EITHER CH 1 NO RESULTS e INPUT YET WHEN ONE OF THE LIGHT BEAMS IS INTERRUPTED THE HYPHEN IS CLEARED WHEN THE LIGHT BEAM IS RESTORED THE HYPHEN RETURNS AND THE RESULT TOTAL FOR THAT INPUT IS INCREMENTED e g T o 1 ONE RESULT COMPLETED BUT 1 TWO RESULTS ON eH H TIMING IN PROGRESS INPUT STOP DATALOGGING MANUALLY PRESS AUTOMATICALLY WHEN NINE RESULTS HAVE BEEN RECORDED 2 4 ON EITHER CH 1 OR CH 2 AFTER DATALOGGING WHEN DATALOGGING STOPS VELA s DISPLAY SHOWS X X X j cg 147 A SPEED RESULT NUMBER FLASHES ADVANCES TO THE NEXT DATA ITEM REVERSES TO THE L
9. MUT wk LY presim good Coole for variations of swnd speed TAP THE HAMMER SHARPLY ON THE ANVIL TO START TIMING THE 2 MICROPHONE STOPS THE TIMING MEASUREMENT OF d WOULD ALLOW THE SPEED OF SOUND TO BE CALCULATED mL evap lt Oxide 73 ISL4 ISL4 EPROM s User NOTES PROGRAM 66 A VELOCITY METER PARAMETER VALUES TWO PARAMETERS ARE USED PARAMETER NO 1 THIS DEFINES THE TRIGGERING EDGES AS IN PROGRAM 05 5 e T x x x 6 4 START Sw START STOP PARAMETER NO 2 THIS IS THE LENGTH OVER WHICH TIMING TAKES PLACE AND ALLOWS VELA TO CALCULATE THE SPEED DIRECTLY LENGTHS IN MILLIMETRES RESULT IN SPEEDS IN mm s AND LENGTHS IN METRES RESULT IN SPEEDS IN m s KEY IN PROGRAM NUMBER HE ENTER TRIGGER SELECTION LENGTH BEING TIMED 6 ENTER THE DISPLAY CLEARS APART FROM THE PROGRAM NUMBER START CLEARS THE DISPLAY IN PREPARATION FOR TIMING PULSES SHOULD BE INPUT DIRECTLY TO THE PULSE INPUT OR VIA THE CHANNEL 1 AMPLIFIER WITH 4 THE EXTERNAL INTERNAL SWITCH SET INTERNAL WHEN TIMING IS COMPLETE THE SPEED IS DISPLAYED AUTOMATICALLY FOR FURTHER TIMINGS PRESS START a d ISL4 ISL4 EPROM s CASE STUDY MK I ONLY SAFETY IO Fo 1 Foi 2 4 Foie 19 User NOTES DETERMINATION OF THE SPEED OF A BULLET THE RESOLUTION OF THE TIMER 100
10. S S Hz eau ISL4 ISL4 EPROM s User Notes APPENDIX A CURRENT MEASUREMENT A TYPICAL SCHOOL METER HAS f s d OF 100 mV e g UNILAB METER 10002 100 M f s d AND OF COURSE THIS VOLTAGE IS CONSTANT WHEN CURRENT SHUNTS ARE ADDED IF THE VELA INPUT RANGE SWITCH IS SET TO 250 mV AND THE VOLTAGE ACROSS THE AMMETER IS MEASURED THEN VELA s DISPLAY WILL BE PROPORTIONAL TO THE CURRENT BEING MEASURED BY THE AMMETER AND THE CONSTANT OF PROPORTIONALITY WILL BE A SIMPLE POWER OF TEN IN OTHER WORDS FOR VELA s DISPLAY TO INDICATE THE CURRENT CORRECTLY THE DECIMAL POINT MUST BE ADJUSTED WHILE LEAVING THE RANGE SWITCH SET 250 mV THIS IS WHAT IS DONE IN THE SCALED D V M AND ENERGY POWER PROGRAMS BULGE HEATER LOAD eke NEA THIS SIMPLE APPROACH OF LITERALLY MEASURING THE VOLTAGE ACROSS THE METER RESULTS IN COMPLICATED WIRING AND IT IS SUGGESTED THAT A SIMPLE PLUG ON UNIT BE CONSTRUCTED FOR VELA e g IF YOU USE A UNILAB 1000 Q METER ISL4 ISL4 EPROM s User Notes APPENDIX A continued DiFFERENT Stowts 1A Cfr EASILY INSERTED es ABS RS 508 720 plastic box RS 5 8 420 RED WRMNALS mm Coil pins positioned to fit Ch 1 and Ch 2 Inputs Check dimensions before drilling IN TRIALS THIS ARRANGEMENT MADE IT MUCH EASIER FOR Rox STAFF AND PUPILS TO SIMPLY VIEW CH 2 AS A CURRENT INTERNAL oF RANGE THE 1k22 RESISTOR REPLAC
11. 6 Touch prod on TP B and adjust VR2 for zero reading 7 Touch prod on TP C and adjust VR4 for a read ing of 7 00 Figure 3 Circuit for pH Meter PUSH TO READ Note this is not the circuit of the RS pH meter 610 540 see text R1 6 carbon film 1 4 cermet mult turn preset 1 2 071 op amp pH Buffer Powders These Buffer Powders represent an important ad vance in the preparation of standard Solutions since they are accurate and dissolve easily The pure dry chemicals used are sealed into a laminate of poly thene and aluminium foil which keeps out moisture and gases that can cause deterioration of the buffer powder For best results a fresh buffer solution should be made up on the day of use Directions Before opening the powder must be shaken down to the bottom of the sachet This may be done con veniently by holding the sachet upright and tapping the bottom edge a hard surface i e a bench top Alternatively the sachet may be held upright and the top flicked with a finger nail The corner of the Sachet should then be cut off and the contents emptied into the vessel used for dissolving the powder The sachet should be tapped to loosen any powder adhering to therinside The water should be freshly distilled or demineralised Distillate from rd water may be heavily contamined with carbon dioxide which should be removed by aeration or boiling prior to use An accu
12. B continued TWO EXPERIMENTAL METHODS ARE POSSIBLE IN a TWO SUCCESSIVE LENGTHS 2 CUT A LIGHT BEAM ENABLING THE SPEED OF EACH TO BE CALCULATED AND THEN THE ACCELERATION IN b ONE CARD LENGTH CUTS TWO LIGHT BEAMS AGAIN THE SPEED THROUGH EACH LIGHT BEAM CAN BE CALCULATED AND i THEN THE ACCELERATION 2 IN BOTH a AND b v yee decia ti t t 45v 4 2 INPUT DO ENSURE THAT THE LIGHT BEAMS ARE CUT BY AN OPAQUE BEWARE CARD oR CARDBOARD MATERIAL AND THAT THE PHOTODIODES TRANSISTORS ARE SHIELDED FROM UNWANTED LIGHT THE APPROPRIATE PARAMETER 4 METHOD AND b WOULD BE lt APPENDIX ISL4 ISL4 1 2 3 4 5 User Notes TEMPERATURE MODULE AND SENSORS THE SENSORS USED ARE CALIBRATED EPOXY COATED THERMISTOR BEADS THESE ARE EMBEDDED IN A LENGTH OF p t f e SLEEVING FOR CHEMICAL AND HEATING PROTECTION AND ARE SEALED WITH EPOXY THE TWO MOST LIKELY FAULTS ARE 1 CHEMICAL ATTACK THIS DESTROYS THE CALIBRATION AND CANNOT BE RECTIFIED 2 ELECTRICAL BREAK THIS CAN BE REPAIRED THE p t f e SLEEVING CAN BE REMOVED WITH CARE AND RESEALED WITH ARALDITE THE SENSOR FORMS PART OF AN R C TIMING CIRCUIT FOR A 555 TIMER BASED ASTABLE CIRCUIT VELA MEASURES THE FREQUENCY OUTPUT AND CONVERTS THIS TO TEMPERATURE THE CIRCUIT IS CALIBRATED USING TWO INTERNAL RESISTORS WHI
13. IS TAKEN SELECTS PULSE SHAPE TWO PARAMETERS lst SELECTS PULSE SHAPE 2nd IS THE DISTANCE BEING TIMED O SELECTS 100 kHz 1 TO 999 SELECTS 0 1 TO 99 9 Hz 0 SELECTS 10 kHz 1 TO 1999 SELECTS 0 1 TO 99 9 David Binney and I hope that the write 4 kbytes of machine A R Clarke May 1985 T ISL4 ISL4 EPROMs NOTES INSERTION OF 1514 IN VELA MK I AFTER REMOVAL OF POWER PROCEDURE 1 UNSCREW THE SCREWS AROUND THE BASE 2 SEPARATE THE BASE FROM THE BOX THIS MUST BE DONE CAREFULLY BECAUSE THE DIGITAL INPUT OUTPUT PORT SOCKET PROTRUDES THROUGH THE SIDE OF THE BOX MY TECHNIQUE IS TO MOVE THE BOX SIDEWAYS A LITTLE WAY AND THEN THE BASE SHOULD SEPARATE FROM THE BOX 3 YOU MAY FIND THAT YOU CANNOT OPEN OUT YOUR VELA SUFFICIENTLY TO LAY BOTH BASE AND UP TURNED BOX ONTO A FLAT WORKING SURFACE AS THE POWER LEAD IS TOO SHORT UNPLUG THE POWER LEAD THERE IS NO NEED TO NOTE THE RELATIVE POSITIONING OF THE RED AND BLACK LEADS I 4 LOCATE THE SPARE SOCKET IC22 ON THE DIGITAL PCB INTO WHICH YOU HAVE TO INSERT THE DUAL 24 PIN CONVERSION SOCKET LOCATE ALSO THE ADDRESS DECODER 74LS138 IC2 DIGITAL 1 PORT lt PossiBL LOCATION GRAPHICS EPROM 1513 7 FLevieue Loca mov 1 p oF EPROM 1512 2 ane Pc es eid a REPE AER NAS gar Siac TUE MOBI gt gt ISL4 ISL4 EPROMs User INSERTION OF IS
14. OR A TRIGGER PULSE ON THE PULSE INPUT CAUSES VELA TO START LOGGING ENERGY THE DISPLAY UPDATES PROVIDING A RUNNING TOTAL A KEYPRESS HALTS THE ENERGY LOGGING AUTO MATICALLY IN THE UNLIKELY EVENT OF THE UPPER LIMIT OF 8 3MJ BEING REACHED THIS PROGRAM WORKS EQUALLY WELL WITH D C AND A C SUPPLIES UP TO 100 Hz APPROX NOTE HOWEVER THAT IF A C IS USED THEN THE SHUNTS USED MUST STILL BE D C SHUNTS i e SIMPLE RESISTORS NOTE ALSO THAT IF V AND I ARE OUT OF PHASE AS IN AN R C CIRCUIT AND LOW FREQUENCY A C IS USED THEN THE SUPPLY AND RETURN OF ENERGY IS APPARENT CONNECTING AN OSCILLOSCOPE TO THE ANALOGUE OUTPUT PROVIDES A DISPLAY OF POWER AGAINST TIME e g INPUTS IN PHASE V L ARE OVT ot RESISTIVE CIRCUIT Prase BY T AS IN 2 on LR Nove PowER ALTERNATES POSITIVE SupPUYy AND RETURN DECIMAL POINT RESELECT CAUSES THE DECIMAL POINT TO FLASH MOVEMENT 2 CAUSES THE DECIMAL POINT TO MOVE TO LEFT OR RIGHT WHEN DECIMAL POINT IS IN THE CORRECT POSITION PRESS JENTER ISL4 ISL4 EPROM s User Notes PROGRAM 64 A POWER METER PARAMETER VALUES NONE USED gt THE DISPLAY INITIALLY INDICATES THE VOLTAGE ON CHANNEL 1 INPUT THE POWER IS CALCULATED BY MONITORING VOLTAGE AND CURRENT AND AVERAGING THE PRODUCT IT IS ASSUMED THAT CHANNEL 1 WILL MONITOR VOLTAGE AND CHANNEL 2 THE CURRENT AS FOLLOWS EXAMPLE TO MONITOR THE POWER OF A 12V 3A IMMERSION
15. TO THE MICRO COMPUTER IN THE SAME WAY AS THE OTHER DATALOGGING PROGRAMS SEE THE TECHNICAL MANUAL AND OR VELA APPLICATIONS BOOK THE VALID DATA IS PRECEDED BY 6 PREAMBLE BYTES FOR MK I VELA s AND 7 PREAMBLE BYTES FOR II VELA s PROGRAM HT BNE CAUTIONARY NOTES NOTE THAT THE FORM OF THE DATA IS DIFFERENT UP TO 1024 DATA BYTES ARE TRANSFERRED 2 DATA BYTES ARE NEEDED FOR EACH RESULT THE TEMPERATURE RESULT IS OBTAINED AS FOLLOWS 1 DECODE THE 2 DATA BYTES THUS X 1st data byte x256 2nd data byte 2 CONVERT TO CELSIUS THUS T 5729 X42482 3 CONVERT KELVIN THUS T 16 3 a EXTENDING THE SENSOR LEADS CAUSES VELA TO GIVE A LOWER TEMPERATURE READING THAN EXPECTED THIS IS DUE TO STRAY CAPACITANCE BETWEEN THE LEADS AND THE EARTH AND IS UNAVOIDABLE IT IS THERE FORE PREFERABLE TO EXTEND THE LOW VOLTAGE POWER LEADS IN ORDER TO MAKE ENVIRONMENTAL MEASURE MENTS AWAY A POWER SOURCE RATHER THAN EXTEND THE SENSOR LEADS b LEAVING THE TEMPERATURE MODULE CONNECTED PREVENTS VELA FROM CORRECTLY SELECTING CH 1 TO CH 4 IN PUTS SO IF YOU WISH TO USE ANOTHER PROGRAM NUMBER REMEMBER TO DISCONNECT THE TEMPERATURE MODULE 27 ISL4 ISL4 s User Notes a PROGRAM 74 A RATEMETER PARAMETER VALUES ANY VALUE IN THE RANGE 1 TO 255 TO DEFINE THE NUMBER OF SECONDS OVER WHICH THE COUNT RATE IS DETERMINED WHATEVER TIME INTERVAL IS CHOSEN THE MAXIMUM PERMITTED COUNT IS 6553 C
16. VELA CAN MONITOR AN ELASTIC COLLISION THAT PREVIOUSLY WOULD HAVE REQUIRED FOUR SCALER TIMERS AND CAN ADDITIONALLY RETURN A DIRECT READING OF SPEED IF REQUIRED WHEN CALCULATING MOMENTUM PUPILS WILL NEED TO PAY DUE ATTENTION TO THE DIRECTION OF TRAVEL THREE VERSIONS OF THE PROGRAM ARE AVAILABLE viz a TIMES ONLY b SPEEDS ONLY c TIMES AND SPEEDS THIS GIVES THE TEACHER THE MAXIMUM CHOICE WHEN IT COMES TO DECIDING WHETHER OR NOT THE MATHEMATICS OF SPEED CALCULATION IS AN INTEGRAL PART OF THE EXPERIMENT EXPERIMENTAL DESIGN ONE POSSIBLE EXPERIMENTAL ARRANGEMENT IS AS FOLLOWS LIGHT WITCH NOTE RANGE SWITCHES SET w 2 5 SEE APPENDIX B FOR ADDITIONAL INFORMATION ON LIGHT L SWITCHES 5 THE DESIGN OF LIGHT SWITCH USED WILL OBVIOUSLY A MATTER OF PERSONAL CHOICE MK 1 ONLY AS VELA MK 1 HAS NO 5V OUTPUT A SEPARATE POWER SUPPLY MUST BE USED SEE APPENDIX B 29 ISL4 ISL4 EPROM s PROGRAM 75 PARAMETER VALUES KEY IN PULSES IN PREPARE FOR DATALOGGING 1 INPUT User Notes DUAL TIMER FOR DYNAMICS A GO THIS DEFINES THE TRIGGERING EDCES AS IN PROGRAM 05 PROGRAM NUMBER ENTER TRIGGER SELECTION TIMING RESOLUTION IS lms MAXIMUM TIME INTERVAL IS 65 SECONDS THE PROGRAM WILL LOOK FOR PULSES ARRIVING AT CH1 INPUT AND CH 2 INPUT INITIALLY THE DISPLAY INDICATES WHETHER CH 1 INPUT IS LO W OR HI GH A CH 2 K
17. through a solid 0 Transfer of energy through a 0 Q Transfer of energy through a gas 0 Monitoring animal activity or road traffic activity secondary worksheets 13 yrs to 16 yrs Muscle fatigue Measuring speed Do clothes keep you warm 0 Testing double glazing 0 Energy save it Heating curves for aluminium 9 Heating curves for aluminium and water 0 i9 Specific heating energies 10 Absorption of infra red radiation 9 21 The strange behaviour of freezing water 0 22 Cooling curves for hexadecan 1 ol and water 0 23 Investigating a heating system 0 24 Monitoring soil or pond temperatures 0 25 Monitoring solar radiation 26 Conservaton of energy 0 Gravitational potential energy to internal energy 27 Measunng the velocity of sound 28 Voice patterns and musical notes 29 Interference of sound waves 30 Conservation of energy Gravitational potential energy to kinetic energy 3 Measuring velocity and acceleration 32 Determination of g 33 Force mass and acceleration F 34 Force mass and acceleration ma 1 O tA tO SET OF WORKSHEETS AND T cCHERS GUIDE Intermediate worksheets 15 yrs to 17 yrs 35 Force mass and acceleration ma 36 Conservation of momentum Elastic collisions 37 Conservation of momentum Inelastic collisions 38 Measuring the force between a snooker cue and ball 39 Mea
18. will help us to maintain the current price of the Mk I list of parts 160 161 62 163 164 165 166 ey iggi ieai bag tas 72 173 1741 IS 176 177 178 179 APPENDICES CONTENTS INSERTION OF EPROM s J ISLA4 INTO MK II VELA s glossep unit s mk E ISL4 INTO MK I VELA s DIGITAL VOLTMETER WITH MOVABLE DECIMAL POINT DIGITAL VOLTMETER DECIMAL POINT amp OFFSET ADJUSTABLE DIGITAL VOLTMETER OFFSET ADJUSTABLE amp SCALING CASE STUDY pH METERING AND MAGNETIC FIELD SENSING AN ENERGY METER A POWER METER A 100 MICROSECOND RESOLUTION TIMER CASE STUDY SPEED OF SOUND MEASUREMENTS A VELOCITY METER CASE STUDY DETERMINATION OF SPEED OF A BULLET PREAMBLE TO TIMING PROGRAMS 67 68 69 AN ACCELEROMETER VIA TIME MEASUREMENTS AN ACCELEROMETER VIA DUAL VELOCITIES 4 TIME AN ACCELEROMETER DIRECT READOUT A DIGITAL THERMOMETER A CAPACITANCE METER A PHASE METER CASE STUDY WAVELENGTH OF SOUND MEASUREMENT A TEMPERATURE DATALOGGER CASE STUDY COOLING CURVES TRANSFER DATA TO MICROCOMPUTER A RATEMETER 0 1 Hz RESOLUTION PREAMBLE TO TIMING PROGRAMS 75 76 77 A TWO CHANNEL REPETITIVE TIMER A TWO CHANNEL VELOCITY METER A TWO CHANNEL TIMER amp VELOCITY METER A LOW FREQUENCY SQUAREWAVE GENERATOR A VARIABLE SINEWAVE OSCILLATOR A DESIGN OF A VOLTAGE CURRENT PLUG ON UNIT LIGHT SWITCHES amp ACCELERATION VELOCITY MEASUREMENT C THE TEMPERATURE MODULE 8 SENSOR Page
19. 0 IS OUTPUT IF THE TEMPERATURE IS OVER 110C THEN HI IS DISPLAYED TO CONVERT THE DISPLAY TO KELVIN PRESS WHICHEVER CHANNEL IS CURRENTLY BEING DISPLAYED IN THIS CASE 1 FURTHER KEYPRESS OF WOULD REVERT TO CELSIUS ALL FOUR CHANNELS ARE DISPLAYED IN EITHER CELSIUS OR KELVIN A MIX IS NOT POSSIBLE TO DISPLAY THE TEMPERATURE BEING SENSED BY ANOTHER SENSOR SIMPLY PRESS THE APPROPRIATE CHANNEL KEY THE THERMAL CAPACITY OF THE SENSOR WHILST NOT AS LOW AS A THERMOCOUPLE IS SIGNIFICANTLY LOWER THAN A MERCURY IN GLASS THERMOMETER IN MANY EXPERIMENTS WHERE THERMOCOUPLES HAVE PREVIOUSLY BEEN USED THE VELA TEMPERATURE SENSOR IS A SUPERIOR ALTERNATIVE GIVING A DIRECT READOUT OF TEMPERATURE e g eel we metes of V lt 50 Ename 4 36 swg conslantin Wire THE CAPACITOR IS DISCHARGED THROUGH THE WIRE CAUSING HEATING OF THE WIRE THE RESULTANT TEMPERATURE RISE CAN BE USED TO DETERMINE THE ENERGY TRANSFERRED FROM THE CAPACITOR AND THUS TO DEMONSTRATE ENERGY V THE ENERGY TRANSFER IS 502 EFFICIENT Calibrate as follows 1 Remove link Lk A 2 Connect battery 3 Connect 150mm of wire insulated to the meter side of Lk A position Bare the other end this acts as a test prod 4 Touch prod on the ea rthy side ofthe coaxial input socket A reading of 0 00 should be ob tained 5 Connect a shorting linkto the coaxial Socket and touch the prod on TP A Adjust VR1 for a zero reading
20. 50 pF 0 2 uF 1 SELECTS THE RANGE 0 1uF 1000 THE VALUE OF THE CAPACITANCE IS DISPLAYED IN STANDARD FORM X XX EA CAPACITANCE EXPONENT VALUE FOR TO 3 SIG FIGS BASE 10 THE CAPACITOR SHOULD BE CONNECTED BETWEEN SYNC OUTPUT AND CHANNEL 1 INPUT WITH THE RANGE SWITCH SET TO 250 mV 1kQ SHOULD BE CONNECTED BETWEEN THE RED AND BLACK TERMINALS OF THE CHANNEL 1 INPUT POLAR CAPACITORS SHOULD HAVE THE POSITIVE LEAD CONNECTED TO SYNC OUT IF NO CAPACITOR IS CONNECTED OR IF THE CAPACITANCE IS TOO SMALL TO BE MEASURED ON THAT RANGE THEN LO IS OUTPUT IF THE CAPACITANCE IS TOO HIGH FOR THAT RANGE THEN HI IS OUTPUT THE METHOD OF MEASUREMENT IS BASED UPON THE CAPACITOR DISCHARGE TIME CONSEQUENTLY THE DISPLAY REFRESH TIME IS VARIABLE AND ALTHOUGH GENERALLY IS 4 1 OR 2 SECONDS CAN BE AS HIGH AS 8 SECS AT THE HIGH END OF THE RANGE FLUCTUATIONS ARE EVIDENT PARTICULARLY ON THE LOW RANGE THIS CAN OFTEN BE IMPROVED SIGNIFICANTLY BY CONNECTING THE NEGATIVE SIDE OF VELA TO EARTH DO NOT CONNECT TO THE NEGATIVE OF THE POWER SUPPLY AND BLOW UP YOUR VELA CHALLENGE YOUR PUPILS TO MAKE A CAPACITOR OUT OF MATERIALS AT HOME THAT WILL FIT INTO A MATCHBOX BE NICE TO THE PUPIL WHO PRODUCES THE CAPACITOR WITH THE SMALLEST VALUE users 4 2100 take the fast reads du until dispan shews ux s take the nant reading when 107 shorting ware
21. ACROSS TO MICROCOMPUTER IS GIVEN ON PAGE 27 EXAMPLE 1 o Ee 2 FILL A KETTLE WITH COLD WATER POP SENSOR INTO KETTLE VIA SPOUT BUT DO NOT REST ON ELECTRIC HEATING ELEMENT KEYPRESS SEQUENCE 3 a aa PRESS START AND SWITCH ON KETTLE WHEN KETTLE BOILS PRESS STopP score 5 LN MODULE ISL4 ISL4 EPROM s PROGRAM 73 EXAMPLE 2 SAFETY DIGITAL Y Port PLUG User Notes TEMPERATURE DATA LOGGER continued PRODUCES AN OSCILLOSCOPE c TRACE LIKE THIS WITH THREE REGIONS OF INTEREST A AND C 8 b me NAPHTHALENE COOLING CURVE Zee LED GLASS VRE NAPHTHALENE OR SIMILAR SENSOR PRESS AND LEAVE NAPHTHALENE TO COOL IN FREE AIR DATALOGGING WILL STOP AFTER v 25 mins 1 Scone 6 AN OSCILLOSCOPE TRACE LIKE THIS PUPILS CAN EXTRACT RESULTS AT 1 min INTERVALS TO PLOT THEIR OWN GRAPHS BY PRESSING time TO ADVANCE 20 DATA ITEMS CHECK YOUR LOCAL REGULATIONS TO SEE WHETHER YOU ARE ALLOWED TO USE NAPHTHALENE ALTERNATIVES ARE HEXADECAN 1 OL 49 39C m pt OR OCTADECANOL ACID 28 29 C m pt NOTE THAT 4 CHANNEL DATALOGGING ALLOWS MEASUREMENTS OF DIFFUSION CONDUCTION CONVECTION AND RADIATION PROCESSES 26 aww ISL4 ISL4 EPROM s PROGRAM 73 Tom c 4 lt OF PATA User NOTES TRANSFER DATA TO MICROCOMPUTERS THIS ROUTINE HANDSHAKES DATA FROM VELA
22. AST DATA ITEM CH SELECTS SPEEDS RECORDED ON CH 2 E UNDER OVER RANGE IF THE TIME RECORDED WAS ZERO THE CORRESPONDING SPEED SHOWN ON THE DISPLAY IS TIMES IN EXCESS OF THE MAXIMUM OF 65 SECS RETURN A SPEED OF LO ISL4 ISL4 EPROM s PROGRAM 77 PARAMETER VALUES PARAMETER NO 1 PARAMETER NO 2 KEY IN PHOTODIODES PREPARE FOR DATALOGGING User Notes DUAL TIMER AND SPEED MEASUREMENT FOR DYNAMICS NS VINA TWO PARAMETERS ARE USED THIS DEFINES THE TRIGGERING EDGES AS IN PROGRAM 05 Sasi dee STA b ss THIS IS THE LENGTH OVER WHICH TIMING TAKES PLACE AND ALLOWS VELA TO CALCULATE THE SPEED DIRECTLY IF THE LENGTH OF THE CARD IS MEASURED IN MILLIMETRES THEN THE SPEED WILL BE IN mm s 7 PROGRAM NUMBER n ENTER TRIGGER SELECTION N m iN Enter EnreR LENGTH OF CARD PULSES FROM THE PHOTODIODE LIGHT SWITCHES SHOULD BE INPUT TO CH 1 INPUT AND CH 2 INPUT INITIALLY THE DISPLAY INDICATES WHETHER CH 1 INPUT IS LO W OR I C 2 KEYPRESS CAUSES THE DISPLAY TO INDICATE WHETHER CH 2 INPUT IS LO W OR HI GH e g BOTH CH 1 INPUT AND CH 2 INPUT ARE PROGRAMMED TO BEHAVE AS SCHMITT TRIGGER INPUTS TO IMPROVE PERFORMANCE RELIABILITY Y CURRENTLY LOW PRESS START THE DISPLAY CHANGES ISL4 ISL4 8 User NOTES PROGRAM 77 DUAL TIMER AND SPEED MEASUREMENT continued RESULTS ON CH 2 EITHER CH 1 AF NON INPUT No
23. AWAY UNTIL THE NEXT POSITION OF ZERO PHASE SHIFT IS FOUND THE MICROPHONE HAS MOVED THROUGH ONE WAVELENGTH USE OF PROGRAM 04 TO MEASURE FREQUENCY WOULD ALLOW A THEORETICAL VALUE FOR THE WAVELENGTH TO BE FOUND ASSUMING THE SPEED OF SOUND IS KNOWN AND THIS COULD BE COMPARED TO THE EXPERIMENTAL VALUE f VELOUTY WAVELENGTH 23 ISL4 ISL4 EPROM s PROGRAM 73 ESSENTIAL EQUIPMENT PARAMETER VALUES KEY IN CHANNEL CHANGE START DATALOGGING STOP DATALOGGING CELSIUS KELVIN DURING DATALOGGING WARNING User Notes 4 CHANNEL TEMPERATURE DATALOGGER THE VELA TEMPERATURE MODULE AND SENSORS MUST BE CONNECTED TO THE I O PORT SEE APPENDIX C ANY VALUE IN THE RANGE 1 TO 999 TO DEFINE THE NUMBER OF SECONDS BETWEEN SAMPLES 3 PROGRAM NUMBER ENTER TIME INTERVAL IN SECS AND THE TEMPERATURE BEING SENSED ON CHANNEL 1 IS DISPLAYED IN CELSIUS THE DISPLAY REFRESHES EVERY 1 4 SECS APPROX TO DISPLAY THE TEMPERATURE BEING SENSED BY ANOTHER SENSOR SIMPLY PRESS THE APPROPRIATE CHANNEL KEY MANUALLY PRESS START AUTOMATICALLY SEND A PULSE TO THE PULSE INPUT DATALOGGING STARTS ON THE POSITIVE EDGE MANUALLY PRESS STOP AUTOMATICALLY WHEN 512 RESULTS HAVE BEEN STORED FROM EACH OF THE FOUR INPUTS CHANGE SCALE BY PRESSING THE KEY FOR THE CHANNEL CURRENTLY BEING DISPLAYED A FURTHER KEYPRESS CHANGES SCALE AGAIN ALL F
24. CH HAPPEN TO CORRESPOND TO TEMPERATURES 1 3 C AND 100 3 CALIBRATION CAN BE CHECKED AS FOLLOWS REMOVE THE BASE OF THE MODULE e SLIDE SWITCHES TO THE RIGHT Cum 9 9 amp d walk CHECK DISPLAYS SHOWS 1 3 C IF TS in NOT ADJUST RIGHT PRESET OF EACH PAIR ONCE SET THIS END OF THE THREE POSITION RANGE SHOULD NEED ONLY Sw TA OCCASIONAL ADJUSTMENT UNLESS BE IN CENTRAL Position EXPOSED TO EXTREMES OF TEMPERATURE Foe SLIDE SWITCHES TO THE LEFT CHECK DISPLAY SHOWS 100 37 NOT ADJUST LEFT PRESET OF EACH PAIR THIS END OF THE RANGE DOES TEND TO DRIFT IT 15 NOT WORTH ADJUSTING IF IT IS LESS THAN 0 2 OUT ACCURACY 40 5 IN RANGE 70 10 EITHER END OF RANGE RESOLUTION 0 1 C FROM 110 C 13 9 0 2 C FROM 13 99 24 99 EXTRA SENSORS CAN EASILY BE MADE IN HOUSE USING THE FOLLOWING PARTS THERMISTOR BEAD R S 151 243 CABLE R S 357 435 p t f e SLEEVING R S 399 833 BANANA PLUGS ARALDITE 42 lows P C Experiment with VELA his publication is intended to help teachers get the best out of their VELA t includes 62 detailed worksheets split into 4 groups ntroductory worksheets up to 14 yrs Measuring temperature 0 How hot are you 0 Changing the temperature 0 Observing water boil 0 Making clouds 0 Thermal conduction along solid rods 0 Does huddling together keep animals warm 0 Transfer of energy
25. D INPUT UPDATED EVERY SECOND RESELECT CAUSES THE DECIMAL POINT TO FLASH 3 MOVES THE DECIMAL POINT LEFT OR RIGHT RETAINS THE PRESENT POSITION OF THE DECIMAL POINT CONSIDER A TEMPERATURE UNIT WITH AN OUTPUT OF 0 250V TO 40 250 V CORRESPONDING TO THE RANGE 0 TO 50 C THE KEY PRESS SEQUENCE PROGRAM NUMBER o OFFSET ADJUSTS THE RANGE FROM 0 000 TO 0 500 RESELECT ENTER MOVES THE DECIMAL POINT SO THAT THE RANGE IS NOW 0 TO 50 0 USE CH2 INPUT SET TO 2501 1 WOULD LIGHT THE VOLTS INDICATOR BUT THE OTHER CHANNELS DO NOT THEREFORE USE OF CH2 CAUSES LESS CONFUSION IN THE UNITS ISL4 ISL4 EPROM s PROGRAM 1621 PARAMETER VALUES PARAMETER NO 1 PARAMETER NO 2 KEY IN EXAMPLE 1 MK II VELA s ONLY User NOTES DIGITAL VOLTMETER WITH OFFSET AND SCALING TWO PARAMETERS ARE USED A NUMBER IN THE RANGE O TO 999 SELECTS THE OFFSET VALUE WHICH IS ADDED TO THE VOLTAGE MEASURED AT ALL OF THE FOUR INPUTS WHEN CALCULATING THE OFFSET IGNORE THE DECIMAL POINT A NUMBER IN THE RANGE O TO 999 SELECTS A SCALING FACTOR IN THE RANGE 0 1 TO 99 9 THE INPUT PLUS OFFSET IS SCALED BY THIS VALUE 6 PROGRAM NUMBER e n N OFFSET VALUE N N SCALING FACTOR THE DISPLAY SHOWS THE SELECTED INPUT UPDATED EVERY SECOND SCALING II REAR INPUTS 1 25 V IF THE STANDARD DVM PROGRAM 00 IS SELECTED VOLTAGES INPUTTED AT THE CH1 CH2 REAR SOCKETS PRODUC
26. E A DISPLAY WHICH IS TWICE THE CORRECT VALUE THEREFORE THE DISPLAYED VALUES MUST BE MENTALLY SCALED BY 0 5 IF YOU WANT TO DISPLAY THE CORRECT VOLTAGES ON THESE TWO REAR INPUTS THE KEYPRESS SEQUENCE WOULD BE 0 ADD ON ZERO 5 Enter SCALE BY 0 5 NOTE THAT CHANNEL 1 WILL LIGHT THE VOLTS INDICATOR BUT CHANNEL 2 WILL NOT LIGHT UP THE INDICATOR 6 T ISL4 ISL4 EPROM s User Notes e CASE STUDY 1 i it d j USEFUL SUGGESTION CASE STUDY pH METERING A HARRIS pH UNIT GIVES AN OUTPUT OF 0 70 TO 6 70 CORRESPONDING TO A pH RANGE OF 0 TO 14 CONSEQUENTLY YOU NEED TO ADD 0 70V AND MULTIPLY BY 10 THE OFFSET PARAMETER WOULD THEN BE 70 0 70 IGNORING DECIMAL POINT AND THE SCALING PARAMETER 100 i e 10 0 THE KEYPRESS SEQUENCE WOULD BE B 7 lo ADD 0 70 o SCALE BY 10 0 USE CH2 INPUT SET TO 2 5V CHANNEL 1 LIGHTS THE VOLTS INDICATOR WHILST THE OTHERS DON T AND SO THE USE OF CH2 CAUSES LESS CONFUSION OF UNITS VELA WILL THEN DISPLAY pH IN THE CORRECT UNITS MAGNETIC FIELD SENSING THE HARRIS MAGNETIC SENSOR C 67830 5 HAS A PRECALIBRATED RANGE FROM O TO 100 MILLITESLA GIVING AN OUTPUT VOLTAGE FROM 0 250 volts TO 0 250 volts RESPECTIVELY IN OTHER WORDS THE OUTPUT IS MATCHED TO THE MOST SENSITIVE VELA RANGE FOR MK II VELA s THE KEYPRESS SEQUENCE bl E 2 5 0 WILL DISPLAY THE MAGNETIC FIELD STRENGTH IN TESLA PRO
27. ES THE 1000 METER EP THE BASIC BOX WITHOUT ADDITIONAL SHUNTS CORRES PONDS TO A CURRENT OF 100 UA YOU ARE ADVISED TO AVOID USE OF DUAL RANGE SHUNTS AS THESE CAN GIVE FALSE RESULTS BECAUSE OF THE COMMON NEGATIVE USED BY CH 1 AND CH 2 INPUTS NOTE THAT THIS ARRANGEMENT EXTENDS THE RANGE OF THE SHUNT e g lmA UP TO 2 5mA BUT BEWARE OF OVERHEATING YOUR SHUNTS ISL4 ISL4 EPROMs User NOTES APPENDIX B THE ORIGINAL USER MANUAL FOR YOUR VELA OUTLINES THREE DESIGNS OF LIGHT SWITCH USED BY COMMERCIAL SUPPLIERS AND SUITABLE FOR USE BY THE D I Y TEACHER A FOURTH AND SIMPLER ALTERNATIVE IN TERMS OF WIRING IS THIS 5 volts 5 volt ovt pat on MUTE l of LIGHT Sv did 16 equivelent CHANNEL 1 L Puust OR INPUT red or te CHAE ma IN UT pes nc VELA THIS WORKS RELIABLY FOR PHOTODIODE R S 305 462 AND DETECTOR R S 306 083 PROVIDED THEY ARE WELL SHIELDED FROM EXTRANEOUS LIGHT AND THAT THE CARD etc USED TO CUT THE LIGHT BEAM IS TRULY OPAQUE ACCELERATION MEASUREMENT Two TECHNIQUES 6 LIGHT Suited xc v Low 52 n 7 5 LIGHT Switch bam 7 i 7 gt u t 1 lt LIGHT 5 SOURCE 1 yG BEAM T FRom RS comPowewts P O box 44 CORBY NORTHANTS ENGLAND ISL4 ISL4 EPROMs User NoTES APPENDIX
28. EYPRESS CAUSES THE DISPLAY TO INDICATE WHETHER CH 2 IS LO W OR HI CH CH 2 INPUT CURRENTLY LOW E BOTH CH 1 INPUT AND CH 2 INPUT ARE PROGRAMMED TO BEHAVE AS SCHMITT TRIGGER INPUTS TO IMPROVE PERFORMANCE RELIABILITY PRESS START THE DISPLAY CHANCES TO NO RESULTS ON CH 2 EITHER 7 CH 2 INPUT NO RESULTS YET ISL4 ISL4 EPROM s User NOTES PROGRAM 75 DUAL TIMER continued WHEN A LIGHT BEAM IS INTERRUPTED THE HYPHEN IS CLEARED WHEN THE LIGHT BEAM IS RESTORED THE HYPHEN RETURNS AND THE RESULT TOTAL IS INCREMENTED e g v ONE RESULT COMPLETED BUT TIMING IN PROGRESS COMPLETED ON CH 1 INPUT STOP DATALOGGING MANUALLY PRESS Stop AUTOMATICALLY WHEN NINE RESULTS HAVE BEEN TAKEN ON EITHER CH 1 OR CH 2 AFTER DATALOGGING WHEN DATALOGGING STOPS VELA s DISPLAY SHOWS LETT XXI 5 RESULT n NUMBER FLASHES TIME ADVANCES TO THE NEXT DATA ITEM Beo REVERSES TO THE LAST DATA ITEM WOULD SELECT TIMINGS RECORDED ON CH 2 INPUT UNDER OVER RANGE IF THE RESULT RECORDED WAS ZERO THEN THE DISPLAYS SHOWS LO THE TIME WAS OVER 65 SECONDS THE DISPLAY SHOWS ISL4 ISL4 EPROM s PROGRAM 76 PARAMETER VALUES PARAMETER NO 1 PARAMETER NO 2 KEY IN PULSES IN PREPARE FOR DATALOGGING User Notes DUAL SPEED MEASUREMENT FOR DYNAMICS 9 TWO PARAMETERS ARE USED THIS DEFINES THE TRIGGERING EDGES AS IN PROGRAM 105 kl
29. HEATER OR LIGHT BULB 2 VovT e OO SUPPLY T SHUNT UNIT SEE APPEND xCA SET CH 1 INPUT TO 25V CH 2 INPUT TO 250 USE A 10A SHUNT MK 1 ONLY THE DECIMAL POINT IS INITIALLY SET FOR INPUT 6 VOLTAGES ON CHANNEL 1 OF 25V AND CURRENTS ON CHANNEL 2 OF 25A THESE DO NOT NEED ADJUSTMENTS SO WHEN READY TO MONITOR POWER PRESS Starr MK ONLY THE DECIMAL POINT IS INITIALLY SET BY THE RANGE SWITCH POSITION AND SO CHANNEL 2 i e THE CURRENT RANGE MUST BE ADJUSTED PRESS CH 2 TO DISPLAY CHANNEL 2 INPUT e g 030 RESELECT ENTER WILL MOVE THE DECIMAL POINT TWO PLACES RIGHT TO GIVE CORRECT DISPLAY i e 3 0 PRESS START MONITOR POWER Irene ISL4 ISL4 EPROM s UsER NOTES PROGRAM 64 POWER METER continued ADDITIONAL NOTES START A START KEYPRESS OR A TRIGGER PULSE ON THE PULSE INPUT CAUSES VELA TO START DISPLAYING i POWER D C THIS PROGRAM WORKS EQUALLY WELL WITH D C AND A C SUPPLIES UP 100 APPROX NOTE HOWEVER THAT IF A C SUPPLY IS USED THEN a D C SHUNTS i e SIMPLE RESISTORS SHOULD STILL BE USED b THE INITIAL MONTTORING ON CHANNEL 1 AND CHANNEL 2 WILL INDICATE AN AVERAGE VOLTAGE OR CURRENT OF ZERO SLOW NOTE ALSO THAT IF V AND I ARE OUT OF PHASE AS AN A C CIRCUIT AND LOW FREQUENCY A C IS USED THEN THE SUPPLY AND RETURN OF POWER MAY BE OBSERVED gt CRO CONNECTING AN OSCI
30. L4 IN VELA MK I continued 5 REMOVE THE ADDRESS DECODER 7418138 FROM IC2 USING AN EXTRACTION TOOL OR BY GENTLY LEVERING WITH A SMALL SCREWDRIVER 6 SELECT THE 16 PIN SOCKET CONVERTER ENSURE THAT THE LEAD LEAVES THE PCB FROM THE LEFT LOCATE ALL LEGS IN THE HOLES OF THE ORIGINAL SOCKET PRESS DOWN FIRMLY BUT CAREFULLY TO INSERT THE CONVERSION SOCKET INTO THE OLD SOCKET 7 ENSURE THAT THE 7415138 HAS THE CUT OUT NOTCH FACING AWAY FROM THE EDGE OF THE BOARD LOCATE ALL LEGS IN THE HOLES OF THE CONVERSION SOCKET PRESS DOWN AND INSERT SELECT THE DUAL 24 PIN CONVERSION SOCKET ENSURE THAT THE EPROM ISL4 IS POSITIONED NEXT TO THE CONNECTING LEAD AND THAT THE CUTOUT NOTCH IS AS IN THE DRAWING CHECK THAT ALL LEGS ARE LOCATED IN THE HOLES OF THE SOCKET THEN PRESS DOWN AND INSERT IF THE LEGS OF THE EPROM ARE TOO WIDE REST THE EPROM ON ITS SIDE ON A FLAT SURFACE AND CAREFULLY BEND THE LEGS SLIGHTLY INWARDS IT CAN BE HELPFUL WHEN INSERTING THE EPROM TO PUT A FINGER UNDER THE PCB AND TO SQUEEZE THE EPROM BETWEEN THUMB AND FINGER WIRE Link Pc ae POSITION THE LEGS OF THE CONVERSION SOCKET IN THE HOLES OF SOCKET IC22 THE EPROM ISL4 SHOULD BE POINTING THE SAME WAY AS 1511 PRESS DOWN FIRMLY AND INSERT IF NOT ALREADY DONE CAREFULLY REMOVE 1511 ORIGINAL ISLL P i REMOVED NEW AND RETURN TO ISL FOR REPROGRAMMING ISLI INSERTED 11 REASSEMBLE YOUR VELA REMEMBERING PLUG
31. LERATION DETERMINATION CLEAR DROP THE CARD THROUGH THE LIGHT BEAMS AND NOTE THE ACCELERATION TRY USING MATERIALS OF DIFFERING MASS AND SHOW THAT THE ACCELERATION IS THE SAME FOR ALL DO ENSURE THAT ALL THE MATERIALS ARE OPAQUE ALTER THE SEPARATION OF THE LIGHT BEAMS AND SHOW THAT THE AVERAGE ACCELERATION IS INDEPENDENT OF DISTANCE TRAVELLED BEWARE OF USING MATERIALS LIKELY TO APPROACH TERMINAL VELOCITY IN THE GIVEN DISTANCE sea APPENDIX O if cand M Ec dimensians vanes of 9 ss Ll rangt 9600 mm sec 0 100 see APPENDIX for ensor details Tu ORANY ISL4 ISL4 EPROM s PROGRAM 67 PARAMETER VALUES KEY IN RESULTS RESTART CONNECT IONS User NOTES THREE TIME MEASUREMENTS TO DETERMINE ACCELERATION DEFINES THE TRIGGERING EDGES AS IN PROGRAM 05 s 7 THE DISPLAY CLEARS APART FROM THE PROGRAM NUMBER mer CLEARS THE DISPLAY READY FOR TIMING PULSES SHOULD BE INPUT DIRECTLY TO PULSE INPUT OR VIA CHANNEL 1 AMPLIFIER WITH EXTERNAL INTERNAL SWITCH SET TO INTERNAL TIMING IS TRIGGERED AS DEFINED BY THE PARAMETER THREE TIMES ARE MEASURED TWO VALUES OF t AS DEFINED ABOVE AND THE TIME BETWEEN MID PULSES e g FOR PARAMETER 1 gt 4 t WHEN TIMING IS COMPLETE TIME t IS DISPLAYED seconde hed is Ut Le 4 is d eres 2 Y ww GIVES t 5 7 7771 Lit ALLOWS YOU
32. LLOSCOPE TO THE ANALOGUE OUTPUT PROVIDES A DISPLAY OF POWER AGAINST TIME e g INPUT WAVEFORMS FOR V k I i e IN PHASE DECIMAL POINT Resevect CAUSES THE DECIMAL POINT TO FLASH MOVEMENT Ben J Fo CAUSES THE DECIMAL POINT TO MOVE TO LEFT OR RIGHT WHEN DECIMAL POINT IS IN THE CORRECT POSITION ISL4 ISL4 EPROM s PROGRAM 165 PARAMETER VALUES KEY IN User NOTES 100 RESOLUTION TIMER THIS DEFINES THE TRIGGERING EDGES AS IN PROGRAM 05 START Sto t Q volts ee eas e L volts o ill T volts 0 16 5 D THE DISPLAY CLEARS BUT FOR THE PROGRAM NUMBER ON THE LEFT START CLEARS THE DISPLAY IN PREPARATION FOR TIMING THE TIME IS DISPLAYED AUTOMATICALLY AFTER THE PULSES ARE APPLIED DIRECTLY TO THE PULSE INPUT OR VIA CHANNEL 1 6 AMPLIFIER WITH THE SWITCH SET INTERNAL TO CARRY OUT FURTHER TIMINGS PRESS START NOTE 1 THAT THE MAXIMUM TIME INTERVAL IS v 6 5 SECONDS 11 THAT IF A SERIES OF PULSES ARRIVE ONLY THE FIRST TIME IS RECORDED AND DISPLAYED 12 ISLA ISLA EPROM s User NOTES CASE STUDY SPEED OF SOUND MEASUREMENTS THE IMPROVED RESOLUTION MAKES THIS PROGRAM IDEAL FOR THE MEASUREMENT OF THE SPEED OF SOUND USE KEYPRESS SEQUENCE s 5 SET EXTERNAL INTERNAL SWITCH TO INTERNAL AND TO 250 mV If d is metres O microphone tkan velky of Un ant bo
33. OUNTS NOTE THAT THIS PROGRAM IS NOT PROTECTED AGAINST ENTRIES OUTSIDE THE RANGE QUOTED AND THAT NON SENSICAL RESULTS WILL BE OBTAINED IF FALSE ENTRY IS MADE KEY IN PROGRAM NUMBER i I TIME INTERVAL CLEARS THE DISPLAY VELA TAKES AN INITIAL READING DURING THE FIRST SECOND AND PUTS THIS ON THE DISPLAY THE DISPLAY IS THEN UPDATED EVERY NNN SECONDS WHERE N N N IS THE CHOSEN TIME INTERVAL THE RESULT IS ROUNDED TO THE NEAREST 0 1 Hz USES THIS PROGRAM EXTENDS THE RANGE OF FREQUENCY MEASUREMENT BELOW THAT POSSIBLE WITH PROGRAM O4 i e WITH WEAK RADIOACTIVE SOURCES OR FOR MEASURE MENT OF MECHANICAL ROTATION FREQUENCIES USING A PHOTODIODE AND INTERRUPT CARD Rd rob ar D MCA DEUM To NANI REN EAD tnter tra aa nA B EXAMPLE DECAY OF PROTACTINTUM 235 FEED PULSES FROM THE GM UNIT INTO THE PULSE INPUT THE DISPLAY WILL UPDATE EVERY 5 SECONDS GIVING THE USER TIME TO READ AND RECORD THE DISPLAY ENABLING OF COUNT RATE WITH TIME MEASURED ALTERNATIVELY INVESTIGATE VARIATION OF COUNT RATE WITH SOURCE GM TUBE SEPARATION FOR A Y RAY EMITTER 28 D ISL4 ISL4 EPROM s sER NorES PROGRAMS 75 76 amp 77 DUAL TIMER AND SPEED MEASUREMENT FOR DYNAMICS EXPERIMENTS PREAMBLE THESE PROGRAMS WERE WRITTEN TO EXTEND AND SIMPLIFY DYNAMICS EXPERIMENTS INVOLVING ELASTIC AND IN ELASTIC COLLISION OF VEHICLES ON AN AIR TRACK A SINGLE
34. OUR CHANNELS ARE DISPLAYED IN EITHER CELSIUS OR KELVIN A MIX IS NOT POSSIBLE p THE LAST RESULT TAKEN ON EACH CHANNEL IS SHOWN ON THE DISPLAY ALL THE RESULTS FOR THE CHANNEL ON DISPLAY ARE OUTPUT TO OSCILLOSCOPE VIA ANALOGUE OUT SO THAT YOU CAN SEE THE DATA RECORDED THE SENSORS DISSOLVE IN ORGANIC SOLVENTS SUCH AS NAPHTHALENE UTR yo 2 pace O F He channel Co wan T 2 5 t 21 4 7 i PENES volue ond channel Atha chon possible by pas The bas ISL4 ISL4 EPROM s User Notes PROGRAM 73 TEMPERATURE DATA LOGGER continued RECOVERY OF DATA THE OUTPUT OPTIONS FOR THIS PROGRAM ARE ALMOST THE SAME AS FOR THE FOUR CHANNEL VOLTAGE DATA LOGGING PROGRAMS 02 AND 03 BUT USERS SHOULD NOTE THE FOLLOWING DIFFERENCES CHART RECORDER VOLTAGE RANGE IS 2 5V TO 2 5V 2 5V z 25C OV 40C AND 2 5V 110C TO OUTPUT ALL 512 RESULTS TAKES v 5 mins OSCILLOSCOPE l FAST ADVANCES REVERSES BY 20 DATA ITEMS RATHER DISPLAY THAN 16 2 IT IS POSSIBLE TO TRANSFER FROM ONE CHANNEL TO ANOTHER WITHOUT HAVING TO RESELECT AND START AGAIN 3 IF FEWER THAN 512 ITEMS OF DATA ARE RECORDED THEN THE PROGRAM IGNORES UNUSED MEMORY SPACE IN ORDER TO READOUT THE DATA RECORDED AS QUICKLY AS POSSIBLE MICROCOMPUTER THE PREAMBLE SENDS ACROSS THE ACTUAL NUMBER OF DATA ITEMS RECORDED INFORMATION ON HOW TO DECODE THE DATA SENT
35. TO STEP BACK THROUGH THE RESULTS START CLEARS THE DISPLAY FOR FURTHER TIMING oeo 080 SEE APPENDIX B FOR TWO OF THE POSSIBLE ARRANGEMENTS 17 4 ISL4 ISL4 EPROM s PROGRAM 68 PARAMETER VALUES PARAMETER 1 PARAMETER 2 KEY IN RESULTS i i MU i ue retenu User NOTES TWO SPEEDS AND THE TIME INTERVAL TO DETERMINE ACCELERATION DEFINES THE TRIGGERING EDGES AS IN PROGRAM 05 UL START S START 5 IS THE DISTANCE INVOLVED e g LENGTH OF INTERRUPT CARD OR DISTANCE BETWEEN DETECTORS SEE APPENDIX B FOR SUGGESTED SENSOR ARRANGEMENTS DISTANCES IN mm GIVE SPEEDS IN mm s DISTANCES IN m GIVE SPEEDS IN m s AND SO ON n PROGRAM NUMBER TRIGGERING SELECTION Iv TIMING DISTANCE THE DISPLAY CLEARS APART FROM THE PROGRAM NUMBER CLEARS THE DISPLAY READY FOR TIMING INPUT PULSES DIRECT TO PULSE INPUT OR VIA CHANNEL 1 AMPLIFIER WITH THE EXTERNAL INTERNAL SWITCH SET 6 TO INTERNAL TIMING IS TRIGGERED AS DEFINED BY PARAMETER 1 THREE TIMES ARE MEASURED TWO VALUES OF t AS DEFINED ABOVE AND THE TIME BETWEEN MID PULSES e g FOR PARAMETER 2 ees haie F ts VELA CALCULATES SPEEDS CORRESPONDING TO L t AND L t ON COMPLETION OF TIMING VELA DISPLAYS vw 1 XXX cives v FWD GIVES t3 4 LAG LED 15 LT BKWD ALLOWS YOU TO REINSPECT V V gt ISL4 ISL4 EPROM s PROGRAM 69
36. VAILABLE AT THE SYNC OUTPUT NOTE THAT THE OUTPUT IMPEDANCE IS x 10kQ FOR VELA MARK II AND 5609 FOR VELA MK I A POWER AMPLIFIER MUST BE USED IF THE OUTPUT IS TO BE C CONNECTED TO A LOW IMPEDANCE CIRCUIT x ACCURACY USERS SHOULD NOTE THAT WHILST THE RESOLUTION IN THE SELECTED FREQUENCY IS lt 17 BELOW 10 Hz THE END OF THE RANGE THE RESOLUTION INCREASES 27 AND SO THE LAST DIGIT HAS NO SIGNIFICANCE volts 50 C boe TERN Od Hz 99 9 He Ico NE time ISL4 ISL4 EPROM s User NOTES PROGRAM 79 SINE WAVE GENERATION ONLY WORKS IF ISL3 ISL3 EPROM IS INSERTED IN YOUR VELA PARAMETER VALUES 0 SELECTS 10 kHz SINE WAVE OUTPUT l TO 999 SELECTS A SINE WAVE OUTPUT IN THE RANGE 0 1 Hz TO 99 9 Hz m QU 4 v THE DISPLAY SHOWS THE FREQUENCY SELECTED AND THE OUTPUT IS AVAILABLE AT THE ANALOGUE OUTPUT NOTE THAT THE OUTPUT IMPEDANCE IS v 10kQ FOR VELA MK II AND V5602 FOR VELA MK I A POWER AMPLIFIER IS ESSENTIAL IF THE OUTPUT IS TO BE USED TO DRIVE LOW IMPEDANCE CIRCUITS SUCH AS VIBRATION GENERATORS ACCURACY USERS SHOULD NOTE THAT WHILST THE RESOLUTION IN THE SELECTED FREQUENCY IS 17 BELOW 6 Hz THIS DETERIORATES PROGRESSIVELY TO A WORST CASE OF v 15 AT THE TOP END OF THE RANGE CONSEQUENTLY THE LAST DIGIT AT HIGHER FREQUENCIES IS MEANINGLESS volts 25 hime JTeoeseo
37. VIDED THE 250 mV RANGE IS SELECTED 7 m ISL4 ISL4 EPROM s User 5 PROGRAM 63 AN ENERGY METER KEY IN 6 NO PARAMETER REQUIRED AND THE DISPLAY INDICATES THE VOLTAGE ON CHANNEL 1 INPUT THE PROGRAM CALCULATES THE ELECTRICAL ENERGY TRANS FORMED BY REPEATEDLY MONITORING VOLTAGE AND CURRENT AND SUMMING THE PRODUCT IT ASSUMES THAT CHANNEL 1 WILL MONITOR VOLTAGE AND CHANNEL 2 THE CURRENT EXAMPLE TO MONITOR THE ENERGY TRANSFORMED BY A 12V 3A IMMERSION HEATER OR LIGHT BULB TO CHANEL 12 CHANNEL Vout SUPPLY lO Amp Stuur ROUND REWRN roe DELS oF THIS SEE APPENDIX A SET CH 1 INPUT TO 25V CH 2 INPUT 250mV USE A 10A SHUNT px MK I ONLY THE DECIMAL POINT IS INITIALLY SET FOR INPUT VOLTAGES ON CHANNEL 1 OF 25V AND CURRENTS ON I CHANNEL 2 OF 25A THESE DO NOT NEED ADJUSTMENTS 6 SO WHEN READY TO MONITOR ENERGY PRESS START MK II ONLY THE DECIMAL POINT IS INITIALLY SET BY THE RANGE SWITCH POSITION AND SO CHANNEL 2 i e THE CURRENT RANGE MUST BE ADJUSTED PRESS TO DISPLAY CHANNEL 2 INPUT e g O 30 RESELECT 7 WILL MOVE THE DECIMAL POINT TWO PLACES RIGHT TO GIVE CORRECT DISPLAY i e 3 0 PRESS START MONITOR ENERGY ISL4 ISL4 EPROM s PROGRAM 63 ADDITIONAL NOTES START STOP A C D C SLOW A C CRO VeL uo vs User NOTES AN ENERGY METER continued A ISTART KEYPRESS
38. e is used to control soil acidity and improve plant growth pH measurement is also of value in many industrial processes and is also beginning to gain prominence in such areas as colour photography processing The value of pH is defined as pH log is the hydrogen ion concentration in the solution At ordinary temperatures pure water will slightly dissociate into hydrogen ions and hydroxyl ions H O Ht Now the concentration of each type of ion is 107 gram molecules per litre and hence the pH value of pure water is pH log 7 107 This figure is conventionally taken to represent neu trality on the pH scale pH Probe and pH buffer _ powders Stock numbers 424 557 and 557 045 Applications Scientific laboratories Educational establishments Processed food industry Drinks industry Aquarium monitoring and control Agriculture and gardening e Colour photography processing If acid is added to water its hydrogen ion concentra tion increases and therefore its pH value decreases Acidity is indicated by pH values below 7 alkalinity by values above 7 Acid has the effect of liberating hydrogen ions in solution and one ofthe traditional tests is the use of litmus paper Acids react with litmus to turn it red alkalis turn it blue However for more accurate mea surements although more precise direct chemical indicators are available electronic methods are now
39. eeds 188 INY
40. icient for a self contained program decision was taken therefore to provide an extra program by using some spare memory space in ISL3 ISL3 Should you require further technical information regarding the programs on ISL4 ISL4 additional to that provided in this manual you are invited to contact David Binney via Instrumentation Software Limited On the next page you will find an overview of the program numbers program description and parameter functions Note that an additional module is required for the 4 channel temperature measurements If you wish to construct this module for yourself write to ISL for circuit details alternatively the built and tested module 4 sensors may be purchased from ISL for 63 This temperature module is manufactured for ISL by Cleveland ITEC who are prepared to give a 12 months guarantee on the module Unfortunately we cannot realistically give a guarantee on the individual sensors but they may be purchased for a few pounds from RS Components see Appendix C Although the insertion of this fourth EPROM presents little difficulty for Mk II users the process is more involved for Mk I users because a fourth EPROM Socket is not available in the original VELA Therefore a sideways EPROM has to be fitted and the original ISL 1 EPROM must be replaced by a new ISL 1 in order to call up the new programs 60 through to 79 Please remember to return the original ISL 1 for reprogramming this
41. id Binney at Acklam 6th Form College Cleveland as a result of experience using the basic VELA and have evolved into their final form over a period of two years The original impetus to provide these facilities was a desire for easier use of VELA by secondary pupils An essential part of this was that VELA should wherever possible display the quantity being measured directly in the correct units Regretfully the 7 segment driver chip does not allow the actual units for temperature power energy etc to be displayed During school trials this has caused no difficulty but teachers may wish to make their own VELA lays to eliminate possible confusion Where possible a numerical link has been maintained between facilities available on ISL4 ISL4 and those on ISL1 ISL1 For example the digital thermometer is program 70 c f digital voltmeter program 00 and the seconds temperature data logger is program 73 c f seconds voltage data logger program 03 Similarly the 100 timer is program 65 and the momentum timer is program 75 c f lms timer program 05 Even so the teachers worked memory is inevitably going to have difficulty keeping track of the options available a memory jogger card will be available shortly from ISL Note that program 79 will only operate if you also have EPROM ISL3 If you do not possess ISL3 ISL3 you may but should not feel cheated The remaining memory space in ISL4 ISL4 was insuff
42. is of the type where the reference electrode is incorporated in the same probe as the main electrode An electrical output proportional to pH allows its use with an amplifier meter to form an accurate pH measuring instrument A hand held digital pH meter suitable for the probe is available stock number 610 540 Probe Characteristics pH range Oto 14pH Response time depending on pH __ Up to 1 mins Temperature range 5 to 100 C Lead termination 500 b n c Output voltage at 7pH OmV 18mV IMPORTANT The probe is despatched with a protective teat containing 3 8M KCI solution fitted over the glass membrane and ceramic junction anda sleeve sealing the filling aperture Re move the teat prior to use and gently shake to allow air bubbles to rise to the top of the probe Pierce a hole in the sleeve through to the filling aperture Always store the probe upright in a pH7 buffer solution NEVER allow the ceramic junction to dry out pH Measurement Next to temperature measurement pH measure ment is one of the most widely used in many areas Of science Essentially is a measure of the con centration of hydrogen ions in a solution and is effectively a measure of acidity Absolute measure ment of pH and the monitoring of its rate of change are important in chemistry but pH measurement is also of importance to the food and drink industries to aquarists to prolong the life of tropical fish and to gardeners where lim
43. m CH 2 INPUT WHEN ONE OF THE LIGHT BEAMS IS INTERRUPTED THE HYPHEN IS CLEARED WHEN THE LIGHT BEAM IS RESTORED THE RETURNS AND THE RESULT TOTAL FOR THAT INPUT IS INCREMENTED e g TWO RESULTS ON RESULT T COMPLETED ON CH1 COMPLETED INPUT AND TIMING IN PROGRESS AUTOMATICALLY WHEN NINE RESULTS HAVE BEEN RECORDED STOP DATALOGGING MANUALLY PRESS sre ON EITHER CH 1 OR CH 2 AFTER DATALOGGING WHEN DATALOGGING STOPS VELA s DISPLAY SHOWS a SECONDS 2 RESULT k aan NUMBER FLASHES THIS PROGRAM OUTPUTS BOTH THE TIMES RECORDED AS SHOWN ABOVE AND THE SPEED CALCULATED THUS PRESS AND THE DISPLAY CHANGES TO SPEED n E es CALCULATED FROM ABOVE TIME i PRESSING AGAIN ADVANCES TO THE NEXT DATA ITEM TIMES FIRST AND THEN SPEED REVERSES TO THE LAST DATA ITEM CH 2 SELECTS TIMES AND SPEEDS RECORDED ON CH 2 INPUT UNDER OVER RANGE IF THE TIME RECORDED WAS ZERO THE DISPLAY SHOWS 10 FOR THE TIME AND HI FOR THE SPEED IF THE TIME WAS OVER 65 SECONDS THE DISPLAY SHOWS HI FOR THE TIME AND LO FOR THE SPEED ISL4 ISL4 EPROM s User Notes PROGRAM 78 SQUARE WAVE GENERATION PARAMETER VALUES O SELECTS A PRECISION 100 kHz PULSE GENERATOR SQUARE WAVE OUTPUT 1 TO 999 SELECTS IN THE RANGE 0 1Hz TO 99 9 Hz mum 7 e b THE DISPLAY SHOWS THE FREQUENCY SELECTED AND THE OUTPUT IS A
44. racy of 296 in the volume of water used is sufficient SRS 8 Remove the lead and insert Lk A Remove the socket link and insert the pH probe 9 Place the pH probe into a neutral solution of pH 7 and adjust VR1 for a reading of 7 00 10 Place the probe into an acid solution of pH 4 Adjust VR3 for a reading of 4 00 Calibration is now complete 11 Repeat 9 and 10 as necessary NOTE The chemicals contained within the probe present no specific hazard but should not be allowed to come into contact with the mouth or food should the probe be broken or its contents become spilled 4pH type acidic Each sachet makes 100 ml of solution The pH value is in accordance with NBS specifications i e 4 01 0 02 pH at 25 C pH values at other temperatures are 80 90 14 09 4 13 4 16 4 21 The solution may be kept for up 2 weeks in a stop pered bottle 7pH type neutral Each sachet makes 200 ml of solution The pH value is 7 00 0 04 at 25 C pH values at other temperatures The solution should not be used for calibration after the day on which it is made up but it may still be used for probe storage R S Components Ltd PO Box 99 Corby Northants NN17 An Flartranam Telephone 0536 201234 standard combination type pH electrode gen eral use in determining the acidity or alkalinity of chemical solutions The design
45. suring the velocity of an air rifle pellet 40 Measuring the efficiency of a d c generator motor 41 Comparing visible light emissions Fluorescent tungsten filament and quartz halogen bulb 42 Range of radioactive emissions 43 Monitoring background radioactivity 44 Half life of protactinium 45 Decay of radon gas Advanced worksheets 16 yrs to 18 yrs 46 Deflection of 8 particles by a magnetic field 47 Capacitor charge and discharge 48 Power dissipation in d c and a c circuits 49 Specific energy of fusion for water 50 Specific energy of vaporisation for water 51 Making a position transducer 32 Motion of an oscillator 53 Measuring the wavelength of sound waves 24 Diffraction and interference of light 55 Energy dissipated by a discharging capacitor direct method 56 Energy dissipated by a discharging capacitor 0 indirect method 57 Factors affecting capacitance 58 Electrical potential around a charged sphere 59 Entropy changes of a gas 0 60 Measuring the self inductance of a coil 61 Power dissipation in resistive and reactive circuits 62 Power dissipation in an inductive circuit These worksheets require VELA to be fitted with the physics eprom 9 These worksheets make use of the temperature module and sensors Use of the temperature module and sensor is optional The physics eprom temperature module and sensors are all available from Instrumentation Software Ltd 7 Gledhow Wood Ave L
46. the accepted norm The RS pH meter stock number 610 540 enables measurement of pH to be made to an accuracy of 0 03 For those wishing to construct their own pH meter the following circuit is offered Please note that the following circuit is not that of the RS pH meter neither is the calibration procedure the same Application pH probe consists of two electrodes between which a potential difference is generated when they are immersed in the solution under test The output voltage is however quite small and processing by high impedance amplifiers is necessary The circuit given is suitable for most applications Operational amplifier IC1 forms a unity gain voltage follower with a very high input impedance Amplifi cation is provided by IC2 and is set by VR3 A reference voltage is adjusted by VR4 such that with zero input from the probe a reading of 7 00 is obtained on the panel meter Figure 1 Probe Schematic GLASS REFERENCE MEMBRANE SOLUTION SLEEVE 40mm 7 S tamam CERAMIC SCREENING COAXIAL JUNCTION cor FILLING LEAD 1m REFERENCE APERTURE ELEMENT Figure 2 Probe Output 150 OUTPUT mV ISL4 ISL4 EPROM s PROGRAM 171 PARAMETER VALUES KEY IN CAPACITOR CONNECTION HIGH RANGE ONLY ELECTROLYTIC CAPS UNDER OVER RANGE GENERAL COMMENTS EXAMPLE U I m a a a AP IST tatc e y User NOTES CAPACTTANCE METER 0 SELECTS THE RANGE
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