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LABORATORY
PROCEDURE MANUAL
Issue Date:
Issue No:
10 May 2007
9
Holder:
<Company Name>
<Company Name>
Issue No.9
Issued by <Company Name>
Procedure Manual
Date: 10 May 2007
Page 2
TABLE OF CONTENTS
1.
1.1.
1.2.
DC VOLTAGE .................................................................................................................. 3
SCOPE - AUTOMATIC GENERATION OF D.C. VOLTAGE FROM 100MV TO 1KV. ................................................. 3
NOTE 6: LOADING CONSIDERATION ON THE 200MV RANGE OF THE CALIBRATOR ............................................. 5
2.1.
2.2.
DC RESISTANCE ............................................................................................................. 6
SCOPE - AUTOMATIC GENERATION OF 2 W IRE RESISTANCE FROM 10 TO 10M. ......................................... 6
SCOPE - AUTOMATIC GENERATION OF 4 W IRE RESISTANCE FROM 0 TO 10K. ............................................ 9
3.1.
3.2.
DC CURRENT ................................................................................................................ 12
SCOPE - AUTOMATIC GENERATION OF D.C. CURRENT IN UP TO 2 AMPS........................................................ 12
SCOPE DC CURRENT SOURCE 2A TO 30A ................................................................................................. 14
4.1.
A.C. VOLTAGE .............................................................................................................. 16
SCOPE - AUTOMATIC GENERATION OF A C VOLTAGE FROM 100MV, 40HZ TO L KHZ...................................... 16
5.1.
A.C. CURRENT .............................................................................................................. 18
SCOPE - AUTOMATED GENERATION OF AC CURRENT 0UA TO 2AMPS, 40HZ TO 1 KHZ .................................. 18
2.
3.
4.
5.
6.
AC CURRENT SOURCE 2A TO 30A ............................................................................... 20
6.1. SCOPE - GENERATION OF AC CURRENT FROM 2A TO 30AMPS .................................................................... 20
7.
7.1.
RCD TIMER ................................................................................................................... 22
SCOPE - RCD TIMER MEASUREMENT USING THE 2100/3200 ....................................................................... 22
8.1.
INSULATION RESISTANCE ........................................................................................... 24
SCOPE – INSULATION RESISTANCE METER CALIBRATION USING THE 2100/3200 ........................................... 24
9.1.
LOOP IMPEDANCE MEASUREMENT ............................................................................. 27
SCOPE – LOOP IMPEDANCE MEASUREMENT USING THE 2100/3200 ............................................................. 27
8.
9.
10. 2100/3200 RCD TIMING TEST ...................................................................................... 30
10.1.
SCOPE - CALIBRATION OF TRANSMILLE 2100 & 3200 16TH ED CALIBRATORS............................................ 30
ELECTRICAL PROCEDURE MANUAL
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Issue No.9
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Procedure Manual
Date: 10 May 2007
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1. DC Voltage
1.1. Scope - Automatic generation of D.C. Voltage from 100mV to 1kV.
1.1.1. Equipment
3000 Series Calibrator
Precision Low thermal Lead set
1.1.2. Connection diagram
1.1.3. Measurement Method:
1)
2)
3)
4)
Allow all equipment sufficient time to stabilise,
Refer to instrument manufactures handbook for operating instructions.
Check environmental conditions e.g. mains voltage/frequency, temperature are within laboratories limits
Use the low thermal lead set to connect the calibrator’s voltage output terminals to the input instrument
under test. (See note 2)
5) Connect guard and earth as required. (See notes below)
6) Check the Zero of the measuring instrument and null if required.
7) Set the output voltage required from the instruments calibration procedure and turn output on. (For
automated calibration ProCal will set the calibrator.) Refer to manufacture’s manual for equipment operation.
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Procedure Manual
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1.1.4. Note 1: Safety Consideration
The calibrator can generate hazardous voltages and great care must be taken to avoid the risk of shock. The
use of shrouded leads, as supplied in the lead set is highly recommended. Note that any capacitance on the
output will become charged to the output voltage, and if the calibrator is set to standby will be left charged
presenting a shock hazard. Leads must not be connected or disconnected when high voltage is present
1.1.5. Note 1: Calibrator Trips back to standby
The output of the calibrator is shorted or the resistance of the load is too low for the calibrator to drive.
Note that for the 2000 series the factory set for the current limit is set to 10mA for safety reasons, this may be
adjusted by internal trimmer up to 25mA if required.
1.1.6. Note 2:Errors due to thermal EMF voltages.
Using the correct test leads is critical for low-level DCV measurements. The 2000 series calibrator’s terminals
are gold plated copper and should be mated with the same type, avoid the use of nickel plated brass banana
plugs. Thermoelectric voltages occur when different metals at different temperatures are connected together.
This property is used in a thermocouple to measure temperature and 10’s of microvolts can easily be generated.
To reduce thermal effects minimize the number of connection, use low thermal plugs made from gold and
copper, and minimize temperature gradients and keep all equipment at the same temperature.
1.1.7. Note 3: Errors due to common mode voltages and pick up.
It is recommend that the negative side of the calibrator’s output is earthed, an internal relay inside the calibrator
can be selected for this, avoiding additional external connections. Letting the output float will allow both terminals
to pick up common mode voltages with respect to earth which and may cause noise and unwanted errors in the
measuring instrument. It is vet important however to only earth the signal at one place, see Note 3. If the
measuring instrument has a guard terminal connect this to the low terminal for the optimum performance when
the calibrator’s output is earthed.
1.1.8. Note 4: Errors due to earth & ground loops.
To avoid errors introduced by earth loop’s only earth the output at one point. As there are often voltage drops in
mains earth wiring, earthing at the calibrator output and at the measuring input will cause earth current to flow
through the connecting lead (which is now in parallel with the mains earth) causing a voltage error.
1.1.9. Note 5: Errors due to Loading.
All voltage sources have output resistance, to which the resistance of connecting leads etc must be added. Most
modern measuring instruments are very high input impedance so the loading effects are negligible. Instruments
with low input impedance such as thermal transfer standards will load the output and an allowance must be
made.
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1.2. Note 6: Loading consideration on the 200mV range of the calibrator
The output impedance of the 200mV range on the 2000 series calibrators is 50 ohms. It is important to note this
when calibrating moving coil type meters, which have low input impedance. Alternatively the 2Volt range can be
used if PC is controlling the calibrator.
1.2.1. Note 7: Errors due Electromagnetic Interference (EMI)
The leads connecting the instruments can pick up both magnet fields generated in all types of mains powered
equipment from transformers, motors etc and RF interference from a mobile phone to a noisy switch mode
power supply in a computer. Keep wire away from mains conductors and use screened cable to reduce noise on
low level signals.
1.2.2. Uncertainties
See spreadsheet
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2. DC Resistance
2.1. Scope - Automatic generation of 2 Wire Resistance from 10 to 10M.
2.1.1. Equipment
3000 Series Calibrator
Precision Low thermal Lead set
2.1.2. Connection diagram
2.1.3. Measurement Method:
1) Allow all equipment sufficient time to stabilise as per manufactures handbook.
2) Check environmental conditions e.g. mains voltage/frequency, temperature are within laboratories limits
3) Use a high insulation screened lead to connect the calibrator’s resistance output terminals to the inputmeasuring instrument under test. (See diagram above)
4) Connect guard and earth as required. (See notes below)
5) Zero the measuring system by shorting the leads together at the calibrator.
6) Set the output required from the instruments calibration procedure and turn output on. (For automated
calibration ProCal will set the calibrator) Refer to manufacture manual for equipment operation.
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2.1.4. Important: Do not exceed the Maximum Power Rating
Care should be taken that the applied voltages and current do not exceed the calibrator’s specification.
Do not connect insulation testers or ductors which test at high currents, exceeding the maximum
ratings will damage the resistor and change the resistance value.
2.1.5. Note 1: Errors due to leakage of test leads on high ohms
To ensure accurate readings on high ohms (10megohms and above) use a cable with either Teflon, or polythene
insulation. Do not use leads made from PVC or extra flex cable. A cable with 100Gohms insulation resistance
will shunt the 1Gohm output by 1%, and the 100Mohm by 0.1%. The screen of the cable should almost always
be connected to earth for minimum noise pick up.
2.1.6. Note 2: Errors due to contact and lead resistance on measurements below
1kohm
When measuring resistance with a two-wire connection the resistance of the test leads and connection become
very important below 1kohm. Although This resistance can be nulled out, (see note 5) this does not remove
contact resistance variation, and in practice it is very difficult to use 2 wire measurements to accuracy better than
a few milli-ohms.
It is critical to make sure all connection are clean, and plugs & sockets are not worn or loose fitting.
For accurate low ohm measurements 4-wire Kelvin type connection must be used.
2.1.7. Note 3: Nulling out lead errors
Firstly short the end of the test leads together and ‘zero’ the DMM before connecting them to the calibrator to null
out lead and connector resistance out.
The 2000 series calibrators are calibrated for 2 wire ohms as the resistance seen at the terminals.
2.1.8. Note 4: Errors due to Earthing and Guarding.
Earthing the resistance output can sometime introduce more noise on higher values in the reading as in some
DMM’s the negative terminal in resistance mode is not the circuit low, but a current sink. Find the best
connection by experimentally method. It may be best to connect earth to screen of the test leads and to the
DMM’s guard, leaving the resistance measuring circuit to float.
2.1.9. Note 5: Errors due self-heating and voltage coefficients
Measuring resistors at high power levels (above 0.5 watts) will cause the resistor to heat up, due to the
temperature co-efficient of the resistor the value will change. As the temperature rise reaches an equilibrium the
value of resistance will also stabilise. When the power is removed the resistor will cool down and return to the
original value. Generally the resistor should be measured at a power level, which will not cause self-heating, less
than 10mW’s for example.
Voltage co- efficient is the change in resistance with voltage, high value film type resistor values will normally
reduce at high voltages, and this effect is very small below 200Volts but may need to be considered above this.
NOTE the resistors in the 2000 series maximum rating is 200V.
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Note 6: Errors due Electromagnetic Interference (EMI)
The leads connecting the instruments can pick up both magnet fields generated in all types of mains powered
equipment from transformers, motors etc and RF interference from a mobile phone to a noisy switch mode
power supply in a computer.
This produces great difficulties for high value (100Kohms) where impedance levels are high and test currents
are low and every effort should be made to use screen leads which must be kept well away from sources of
interference e.g. mains cables, computers, interface cables etc.
Note
To help reduce AC impedance the highest values of resistance in the 2000/3000 series calibrators have a 100pF
capacitance across.
2.1.11.
Note 7: Measuring resistance with AC.
Please note that this falls outside the scope of this procedure and has been included only for completeness
Bridges often use AC to measure resistance, the resistors used in the 2000 series up to 100Kohms are of foil
construction or non inductively wound and can be measured using AC up to 1kHz with little change in accuracy.
2.1.12.
Uncertainties
See Spreadsheet
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2.2. Scope - Automatic generation of 4 Wire Resistance from 0 to 10k.
2.2.1. Equipment
3000 Series Calibrator
Precision Low thermal Lead set
2.2.2. Connection diagram
2.2.3. Measurement Method:
1)
2)
3)
4)
5)
6)
Allow all equipment sufficient time to stabilise as per manufactures handbook.
Check environmental conditions e.g. mains voltage/frequency, temperature are within laboratories limits
Use a high insulation, low thermal screened lead and connect both the voltage sense leads, (to the top
terminals) and the current drive leads the calibrator’s output to the measuring systems input. (see diagram
above)
Connect guard and earth as required. (See notes below)
Select the zero ohms output from the calibrator and zero the measurement system
Set the output resistance required from the instruments calibration procedure. Turn output on. (For
automated calibration ProCal will set the calibrator.) Refer to manufacture manual for equipment operation.
ELECTRICAL PROCEDURE MANUAL
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2.2.4. Important: Do not exceed the Maximum Power Rating
Care should be taken that the applied voltages and current do not exceed the calibrator’s specification.
Do not connect insulation testers or ductors which test at high currents, exceeding the maximum
ratings this will damage the resistor and change the resistance value.
2.2.5. Note 1: Errors due to thermals on low ohms.
Most resistance measuring instruments pass a DC current through the resistor and measure the voltage drop
across it. For low values below 100 ohms and at low currents (10mA) often used by modern Digital multi meters
makes the voltage to measure typically 100mV for 10ohms. A thermal generated EMF of 10uV in the test leads
will give an error of 50ppM.
Many high performance DMM’s have an ohms compensation function to automatically null this out. This should
be used to improve the reading. If such a function is not available great care should be taken to use low thermal
test leads.
2.2.6. Note5: Nulling out measurement systems zero
Connect up sense and current wire to the calibrator, select zero ohms output on the calibrator and null the
measurement system.
The 3000 series calibrators are calibrated for 4 wire ohms as the resistance relative to the zero position
2.2.7. Note 6: Errors due to Earthing and Guarding.
Earthing the resistance output can sometime introduce more noise on higher values in the reading as in some
DMM’s the negative terminal in resistance mode is not the circuit low, but a current sink. Find the best
connection by experimentally method. It may be best to connect earth to screen of the test leads and to the
DMM’s guard, leaving the resistance measuring circuit to float.
The 3000 series calibrators can internally earth the low side of the output. The condition of this is shown on the
display and by a green front panel LED.
2.2.8. Note 7: Errors due self heating and voltage coefficients
Measuring resistors at high power levels (above 0.5 watts) will cause the resistor to heat up, due to the
temperature coefficient of the resistor the value will change. As the temperature rise reaches an equilibrium the
value of resistance will also stabilise. When the power is removed the resistor will cool down and return to the
original value. Generally the resistor should be measured at a power level, which will not cause self-heating, less
than 10mW’s for example.
Voltage coefficient is the change in resistance with voltage, high value film type resistor values will normally
reduce at high voltages - this effect is very small below 200Volts but may need to be considered above this.
NOTE the resistors in the 3000 series maximum rating is 200V.
2.2.9. Note 8: Errors due Electromagnetic Interference (EMI)
The leads connecting the instruments can pick up both magnet fields generated in all types of mains powered
equipment from transformers, motors etc and RF interference from a mobile phone to a noisy switch mode
power supply in a computer.
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This produces great difficulties for high value (100Kohms) where impedance levels are high and test currents
are low and every effort should be made to use screen leads which must be kept well away from sources of
interference e.g. mains leads, computers, interface leads etc.
Note
To help reduce AC impedance the highest values of resistance in the 3000 series calibrator have a 100pF
capacitance across.
2.2.10.
Note 9: Measuring resistance with AC.
Please note that this falls outside the scope of this procedure and has been included only for completeness
Bridges often use AC to measure resistance, the resistors used in the 3000 series up to 100Kohms are of foil
construction or non inductively wound and can be measured using AC up to 1kHz with little change in accuracy.
2.2.11.
Uncertainties
See Spreadsheet
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3. DC Current
3.1. Scope - Automatic generation of D.C. current in up to 2 Amps.
3.1.1. Equipment
3000 Series Calibrator
Precision Low thermal Lead set
3.1.2. Connection diagram
3.1.3. Measurement Method:
1) Allow all equipment sufficient time to stabilise as per manufactures handbook.
2) Check environmental conditions e.g. mains voltage/frequency, temperature are within laboratories limits
3) Use a 1 metre high insulation screened lead to connect the calibrator’s current output terminals to the inputmeasuring instrument under test. (See diagram above)
4) Connect guard and earth as required. (See note 1 below)
5) Check the Zero the measuring instrument and null if required.
6) Set the output current required from the instruments calibration procedure and turn output on (for automated
calibration Procal will set the calibrator.)
7) Refer to manufacture manual for equipment operation.
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3.1.4. Caution 1:
When using currents above 1 amp take care to ensure the measuring instrument is on the correct range
and the correct input is being used.
3.1.5. Note 1: Calibrators Compliance (or burden) voltage exceeded
If the calibrator trips back into standby the calibrator’s output may be open circuit or the resistance to
high to drive the set current.
3.1.6. Note 2: Errors due pick up and EMI interference when calibrating below
1mA
Accurate measurement of Currents below 100uA can easily become swamped out by stray magnetic fields &
pick up. Unlike DC voltage where impedances are very low a current source has very high output impedance,
which is therefore more susceptible to induced noise, making the use of screened leads essential for accurate
measurements. Guards should be connected to earth and also the low side of the output.
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3.2. Scope DC Current Source 2A to 30A
3.2.1. Equipment
3000 Series Calibrator
Precision Low thermal Lead set
3.2.2. Connection diagram
3.2.3. Measurement Method:
1) Allow all equipment sufficient time to stabilise as per manufactures handbook.
2) Check environmental conditions e.g. mains voltage/frequency, temperature are within laboratories limits
3) Use 30 Amp test leads to connect from the calibrator to the 30 Amp input terminals of the measuring
instrument under test. Note high currents can melt low current test leads. (See diagram above)
4) Check the Zero of the measuring instrument and null if required.
5) Set the output current required from the instruments calibration procedure. Turn output on. (For automated
calibration ProCal will set the calibrator.) Refer to manufacture manual for equipment operation.
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3.2.4. Caution 1:
When using High currents take care to ensure the measuring instrument is on the correct range and the correct
input is being used.
3.2.5. Caution 2:
Inductive loads, coils etc can cause large back EMF voltages if suddenly disconnected, causing arcing which
can damage instruments, always turn of output first before disconnecting.
3.2.6. Note 1: Calibrators Compliance (or burden) voltage exceeded
If the calibrator trips back into standby the calibrator’s output may be open circuit or the resistance to high to
drive the set current.
3.2.7. Note 2: Errors Due to self-heating.
The accuracy of high Currents measurements are effected by self-heating increasing the temperature of the
current shunts used to measure the current. This increase in temperature will change the value of the resistor,
and hence the reading, In examples where this effect is very significant it may be necessary to record the time
between the current first being applied and the measurement taken, or the temperature of the shunt.
3.2.8. Uncertainties
See Spreadsheet
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4. A.C. Voltage
4.1. Scope - Automatic generation of A C voltage from 100mV, 40Hz to l kHz.
4.1.1. Equipment
3000 Series Calibrator
Precision Low thermal Lead set
4.1.2. Connection diagram
4.1.3. Measurement Method:
1) Allow all equipment sufficient time to stabilise as per manufactures handbook.
2) Check environmental conditions e.g. mains voltage/frequency, temperature are within laboratories limits
3) Use a 1metre screened lead set to connect the calibrator’s voltage output terminals to the input instrument
under test. (See diagram above)
4) Connect guard and earth as required. (See notes below)
5) Set the output voltage & frequency required from the instruments calibration procedure. Turn output on. (For
automated calibration ProCal will set the calibrator.) Refer to manufacture manual for equipment operation.
4.1.4. Note 1: Safety Consideration
The calibrator can generate hazardous voltages and great care must be taken to avoid the risk of shock.
The use of shrouded leads, as supplied in the lead set is highly recommended.
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4.1.5. Note 1: Errors due to common mode voltages and pick up.
It is recommend that the negative side of the calibrator’s output is earthed, an internal relay inside the calibrator
can be selected for this, avoiding additional external connections. Letting the output float will allow both terminals
to pick up common mode voltages with respect to earth which and may cause noise and unwanted errors in the
measuring instrument. It is vet important however to only earth the signal at one place, see Note 3. If the
measuring instrument has a guard terminal connect this to the low terminal for the optimum performance when
the calibrator’s output is earthed.
4.1.6. Note 2: Errors due to earth & ground loops.
To avoid errors introduced by earth loop’s only earth the output at one point. As there are often voltage drops in
mains earth wiring, earthing at the calibrator output and at the measuring input will cause earth current to flow
through the connecting lead (which is now in parallel with the mains earth) causing a voltage error.
4.1.7. Note 3: Errors due to Loading.
All voltage sources have output resistance, to which the resistance of connecting leads etc must be added. Most
modern measuring instruments are very high input impedance so the loading effects are negligible. Instruments
with low input impedance such as thermal transfer standards will load the output and an allowance must be
made. Capacitance of cables will also cause loading effects.
4.1.8. Note 4: Errors due Electromagnetic Interference (EMI)
The leads connecting the instruments can pick up both magnet fields generated in all types of mains powered
equipment from transformers, motors etc and RF interference from a mobile phone to a noisy switch mode
power supply in a computer. Keep test leads away from mains conductors and use screened cable to reduce
noise on low level signals
4.1.9. Uncertainties
See Spreadsheet
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5. A.C. Current
5.1. Scope - Automated generation of AC current 0uA to 2Amps, 40Hz to 1 kHz
5.1.1. Equipment
3000 Series Calibrator
Precision Low thermal Lead set
5.1.2. Connection diagram
5.1.3. Measurement Method:
1) Allow all equipment sufficient time to stabilise as per manufactures handbook.
2) Check environmental conditions e.g. mains voltage/frequency, temperature are within laboratories limits
3) Use a 1 metre, high insulation screened lead to connect the calibrator’s resistance output terminals to the
input-measuring instrument under test. (See diagram above)
4) Connect guard and earth as required. (See note below)
5) Set the output current & frequency required from the instruments calibration procedure and turn output on.
(For automated calibration ProCal will set the calibrator.) Refer to manufacture manual for equipment
operation.
5.1.4. Caution
When using currents above 1 amp take care to ensure the measuring instrument is on the correct range
and the correct input is being used.
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5.1.5. Note 1: Calibrators Compliance (or burden) voltage exceeded.
If the calibrator trips back into standby the calibrator’s output may be open circuit or the impedance is
to high to drive the set current. Note the impedance (AC resistance) of inductive loads, such as coils,
increases with frequency, which may limit the maximum frequency that can be used without
exceeding the compliance voltage.
5.1.6. Note 2: Errors due to AC current leakage when calibrating below 1mA
When connecting to other AC mains powered it is critical to use correct guarding is used. Currents
can flow through the capacitive coupling to earth via the mains transformer inside the instrument
instead of through the measuring circuit. The output from2000 series calibrator is sensed as the
current flowing out of the positive terminal, this allowing the negative terminal of the calibrator and the
measuring instrument guard to simple be earthed. To stop current from the positive terminal escaping
down to earth before passing through the instruments measuring circuitry all capacitive route to earth
should be removed, the most common route is to the screen of the connecting cable which if the
cable is short the capacitance will be small and the effect negligible. Alternatively the screen could be
driven with an active guard, which is beyond the scope of this procedure.
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6. AC Current Source 2A to 30A
6.1. Scope - Generation of AC Current from 2A to 30Amps
6.1.1. Equipment
3000 Series Calibrator
Precision Low thermal Lead set
6.1.2. Connection diagram
6.1.3. Measurement Method:
1) Allow all equipment sufficient time to stabilise as per manufactures handbook.
2) Check environmental conditions e.g. mains voltage/frequency, temperature are within laboratories limits
3) Use 30 Amp test leads to connect from the calibrator to the 30 Amp input terminals of the measuring
instrument under test. Note high currents can melt low current test leads. (See diagram above)
4) Set the output current required from the instruments calibration procedure. Turn output on. (For automated
calibration ProCal will set the calibrator.) Refer to manufacture manual for equipment operation.
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6.1.4. Caution 1
When using High currents take care to ensure the measuring instrument is on the correct range and the
correct input is being used.
6.1.5.
Caution 2
Inductive loads, coils etc can cause large back EMF voltages if suddenly disconnected, causing arcing
which can damage instruments, always turn of output first before disconnecting.
6.1.6. Note 1: Calibrators Compliance (or burden) voltage exceeded.
If the calibrator trips back into standby the calibrator’s output may be open circuit or the impedance is to high to
drive the set current. Note the impedance (AC resistance) of inductive loads, such as coils, increases with
frequency, which may limit the maximum frequency that can be used without exceeding the compliance voltage.
6.1.7. Note 2: Thermal Shut down
The calibrators power amplifier becomes overheated an internal sensor shuts the output off.
(STBY !! is displayed). The user must wait for the amplifier to cool down again before the output can be turned
on.
6.1.8. Note 3: Errors Due to self-heating.
The accuracy of high Currents measurements are effected by self-heating increasing the temperature of the
current shunts used to measure the current. This increase in temperature will change the value of the resistor,
and hence the reading, In examples where this effect is very significant it may be necessary to record the time
between the current first being applied and the measurement taken, or the temperature of the shunt.
6.1.9. Uncertainties
See Spreadsheet
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7. RCD Timer
7.1. Scope - RCD Timer measurement using the 2100/3200
This procedure covers the automatic testing of any digital loop tester and any electrical combination tester, which
includes a RCD tester function. The 2100 is capable of testing RCD tester functions: RCD test current from 3mA to 3A: RCD trip times from 20ms to 5s:Current multipliers, I, 2I, 5I, ½ I
7.1.1. Equipment
Transmille 3200 16th Edition Calibrator
7.1.2. Connection diagram
7.1.3. Measurement Method
1) Allow all equipment sufficient time to stabilize as per manufactures handbook.
2) Check environmental conditions e.g. mains voltage/frequency, temperature are within laboratories limits
3) It should be firstly checked to see if the RCD tester which is going to be calibrated, is designated for use on
a particular level of mains supply. This should be evident on the rating plate of the unit to be tested. A variac
should have the 2100 plugged into it’s output and the voltage set to the corresponding value on the rating
plate. (220V, 230V, 235.5V or 240V). Most modern RCD testers are immune to voltage changes. The older
one’s are not. Therefore it is advisable to always have a variac supplying the 2100 regardless of age.
4) Connect the RCD tester to the 2100 IEC socket with the calibrated adaptor lead
5) Set the test current required on the 2100 and the tester from the instruments calibration procedure and
press the test button on the RCD tester, (For automated calibration Procal will set the calibrator.)
6) Refer to manufacture’s manual for equipment operation.
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7.1.4. Caution
Live mains voltage is present on the 3200 output during this test.
Care should be taken to avoid risk of electric shock.
7.1.5. Note 1: 3200 Mains Supply
The 2100 must be connected to an unprotected supply for this test as current is passed from live to
earth, which will trip any RCD, protected supply.
7.1.6. Note 2: 3200 displays warning message
The tester may have a fault where excessive current is flowing in the earth conductor.
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8. Insulation Resistance
8.1. Scope – Insulation Resistance meter calibration using the 2100/3200
This procedure covers the measurement of high value resistance of any analogue or digital insulation testers
and any electrical combination tester, which includes an insulation tester function.
The 2100 is capable of testing insulation tester resistance functions: Resistance up to 1000V in the range 0.01MΩ to 10GΩ
8.1.1. Equipment
Transmille 3200 16th Edition Calibrator
8.1.2. Connection diagram
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8.1.3. Measurement Method
1) Allow all equipment sufficient time to stabilize as per manufactures handbook.
2) Check environmental conditions e.g. mains voltage/frequency, temperature are within laboratories limits
3) Connect the insulation tester to the 4mm sockets at the bottom left of the calibrator using the set of silicon
test leads, or the leads supplied with the instrument.
4) Select the correct procedure from the file for a manual calibration or from the Procal list for automated
calibration. (This is normally an automatic function of Procal software when the instrument has been
calibrated before).
5) Verify the procedure is the correct one and that the customer has not asked for any special requirements. All
calibration within the Laboratory will be carried out using a procedure, which has been written and verified
before use.
6) Following the procedure set the function and resistance required on the 2100, and press the test button on
the tester, (For automated calibration Procal will set the calibrator.) Note - check battery voltage on tester.
7) Refer to manufacturers manual for equipment operation.
8.1.4. Uncertainties
See spreadsheets. When using ProCal the uncertainties are calculated as the test is performed, the calibration
engineer entering the noise & flicker data together with the measurement.
8.1.5. Caution :
Insulation testers produce high voltages, care should be taken to avoid shock.
8.1.6. Note 1: Test Leads
Test leads are important in the case of insulation testers. Good quality, high insulation resistance leads need to
be used when testing to avoid leakage paths (to benches and the other test lead being used, which could have a
shunting effect on the higher value resistance calibration)
8.1.7. Note 2: Stability of readings
Calibration at resistance values above 10MΩ requires care. As well as observing the requirements for test leads
above, ‘Bodily’ movement, near to the test leads and calibrator, need to be avoided, to prevent inducement of
static voltages being coupled into the test leads.
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8.1.8. Note 3: Test Leads
Test leads are an integral part of loop tester calibration. As described above, only the extension IEC/13 socket
lead calibrated with the 2100 may be used.
Generally, instruments returned for calibration will have their own dedicated test lead supplied. This must be
used and on booking in the instrument for calibration, an ID Number will have been placed on the lead linking it
to the UUT. On the certificate, reference should e made stating, that the UUT was calibrated with the test lead
(s) supplied.
If no lead is supplied, then the laboratory reference leads should be used. These are standard leads for a
variety of loop testers, which are calibrated. Reference to the Laboratory leads having been used,
should be refereed to on the certificate front page.
8.1.9. Note 4: Mains pickup
Test leads and the UUT should be kept away from stray electrical fields (mains leads carrying mains voltages
near to the test set up, can again cause coupling of noise into the test system)
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9. Loop Impedance Measurement
9.1. Scope – Loop Impedance Measurement using the 2100/3200
This procedure covers the automatic testing of any analogue or digital loop tester and any electrical combination
tester, which includes a loop tester function.
The 2100/3200 is capable of testing loop tester functions: Resistance in the range 0.05Ω to 1kΩ (lowest value dependant on the local supply loop impedance)
9.1.1. Equipment
Transmille 3200 16th Edition Calibrator
9.1.2. Connection diagram
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9.1.3. Measurement Method
1) Allow all equipment sufficient time to stabilize as per manufactures handbook.
2) Check environmental conditions e.g. mains voltage/frequency, temperature are within laboratories limits
3) Refer to the calibrator’s user manual for operating instructions.
4) Connect the Loop tester to the 2100 IEC socket with the calibrated adaptor lead.
5) The residual loop impedance of the source, up to the IEC socket first needs to be determined, whether the
2100 is being used manually or under computer control. Select the loop function on the calibrator’s menu
and then press the ‘Auto Loop’ function. This will take about 30 seconds to determine the loop. This must be
carried out if the calibrator is plugged into an alternative supply or at the beginning of any new loop test
sequence.
6) Select the correct procedure from the file for a manual calibration or from the Procal list for automated
calibration. (This is normally an automatic function of Procal software when the instrument has been
calibrated before).
7) Verify the procedure is the correct one and that the customer has not asked for any special requirements. All
calibration within the Laboratory will be carried out using a procedure, which has been written and verified
before use.
8) Following the Procedure Set the loop resistance required on the 2100, and press the test button on the Loop
tester, (For automated calibration Procal will set the calibrator.)
9.1.4. Uncertainties
See spreadsheets. When using Procal the uncertainties are calculated as the test is performed, the calibration
engineer entering the noise & flicker data together with the measurement.
9.1.5. Caution
Live mains voltage is present on the 2100/3200 output during this test.
Care should be taken to avoid risk of electric shock.
9.1.6. Note 1: 2100/3200 Mains Supply
The 2100/3200 must be connected to an unprotected supply for this test as current is passed from live to earth,
which will trip any RCD, protected supply.
9.1.7. Note 2: 2100/3200 displays warning message
The tester may have a fault where excessive current is flowing in the earth conductor.
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9.1.8. Note 3: Test Leads
Test leads are an integral part of loop tester calibration. As described above, only the extension IEC/13 socket
lead calibrated with the 2100 may be used.
Generally, instruments returned for calibration will have their own dedicated test lead supplied. This must be
used and on booking in the instrument for calibration, a number will have been placed on the lead linking
it to the UUT. On the certificate, reference should be made stating, that the UUT was calibrated with the test lead
(s) supplied.
If no lead is supplied, then the laboratory reference leads should be used. These are standard leads for a
variety of loop testers, which are calibrated. Reference to the Laboratory leads having been used,
should be refereed to on the certificate front page.
9.1.9. Note 4: Cleanliness of connections
Dirty mains plugs, as well as worn mains plugs, can lead to significant errors at the lower loop value tests. The
mains plug should be inserted and removed from adaptor lead several times to ensure oxidization has not built
up on either the test lead with the UUT or adaptor lead.
9.1.10.
Note 5: Mains voltage noise / variations.
Loop testers which have a 15mA loop test, make the measurement, sampled about 30 times, over the cause of
about 30 seconds. In this time, mains borne noise and voltage variations are going to occur, even on the best of
installations. Noise can happen, just with a soldering iron switching on its heater!
If a totally incorrect reading is recorded or the noise flag comes up on the UUT, the test should be carried out
again.
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2100/3200 RCD Timing Test
10.1. Scope - Calibration of Transmille 2100 & 3200 16th Ed Calibrators
10.1.1.
Equipment
Transmille 2100 or 3200
Digital Storage Oscilloscope TN627
Trip time test box
10.1.2.
Connections
RCD: 10mA 200ms
2100/3200
DSO
Earth
Sig
Trig
Ch1 Ext Trig
Earth
START
10.1.3.
Test Box Description
The ‘START’ control is a 2 pole switch. Pole 1 gives a low to high signal to trigger the oscilloscope. Pole 2
switches a load resistor between line and earth, which has a 50:1 divider tapping to connect to CH1 of the
oscilloscope.
Note
The test box does not contribute to the overall uncertainties of the measurement system, as the scope stores the
waveform before the trigger event.
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Measurement Method
The equipment settings are:
2100 or 3200: Set RCD, Zero crossing mode, 10mA test current, trip time as required below.
Oscilloscope: Set 5V/div amplitude, timebase as required below, external trigger set to 1V, Normal trigger.
Horizontal start after 1 div.
20ms to 40ms trip time.
Connect equipment as in drawing above and settings as described previously.
Set timebase to 5ms/div
Set 2100/3200 for the RCD time between 20ms and 40ms as required
Press ‘TEST’ button on 2100/3200.
Set switch on to ‘START’ on test box
Use cursors on the oscilloscope to measure the displayed RCD time between the 1st zero crossing and switch
off point.
40ms to 100ms trip time.
Connect equipment as in drawing above and settings as described previously.
Set timebase to 20ms/div
Set 2100/3200 for the RCD time between 40ms and 100ms as required
Press ‘TEST’ button on 2100/3200.
Set switch on to ‘START’ on test box
Use cursors on the oscilloscope to measure the displayed RCD time between the 1st zero crossing and switch
off point.
100ms to 400ms trip time.
Connect equipment as in drawing above and settings as described previously.
Set timebase to 50ms/div
Set 2100/3200 for the RCD time between 100ms and 400ms as required
Press ‘TEST’ button on 2100/3200.
Set switch on to ‘START’ on test box
Use cursors on the oscilloscope to measure the displayed RCD time between the 1st zero crossing and switch
off point.
400ms to 700ms trip time.
Connect equipment as in drawing above and settings as described previously.
Set timebase to 100ms/div
Set 2100/3200 for the RCD time between 400ms and 700ms as required
Press ‘TEST’ button on 2100/3200.
Set switch on to ‘START’ on test box
Use cursors on the oscilloscope to measure the displayed RCD time between the 1st zero crossing and switch
off point.
700ms to 900ms trip time.
Connect equipment as in drawing above and settings as described previously.
Set timebase to 200ms/div
Set 2100/3200 for the RCD time between 700ms and 900ms as required
Press ‘TEST’ button on 2100/3200.
Set switch on to ‘START’ on test box
Use cursors on the oscilloscope to measure the displayed RCD time between the 1st zero crossing and switch
off point.
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