Lake Shore 475, Руководство пользователя

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Lake Shore Model 475 Gaussmeter User’s Manual
8-12 Service
16. Configure the 475 excitation current to -100 mA (HALLCS 1;CSMODE 3).
17. Read the current using the DVM. Store as AVGNEGCURRENT.
18. Connect the DVM voltage input across the 3
Ω
resistor.
19. Read the voltage using the DVM. Store as AVGNEGVOLTAGE.
20. Calculate EXPECTEDRESISTANCE = (AVGPOSVOLTAGE - AVGNEGVOLTAGE) / (AVGPOSCURRENT -
AVGNEGCURRENT).
21. Calculate the Gain Calibration Factor (GCF) = EXPECTEDRESISTANCE/ ACTUALRESISTANCE. Test this
factor to be 1.0, ±2%.
22. Send the Gain Calibration Factor (GCF) to the Model 475 (CALG 1,5,<GCF>).
23. Connect the 3
Ω
resistor across the Gaussmeter input of the Model 475 using a proper 4-lead connection.
24. Configure the 475 for 100 mA excitation current (HALLCS 1), normal excitation current mode (CSMODE 1).
25. Read the resistor using the 475 (RDGOHM?). Verify the reading to be EXPECTEDRESISTANCE ±0.01%.
26. Connect the 300 m
Ω
resistor across the Gaussmeter input of the Model 475 using a proper 4-lead connection.
27. Configure the 475 for 100 mA excitation current (HALLCS 1).
28. Read the resistor using the 475 (RDGOHM?). Store as EXPECTEDRESISTANCE.
29. Configure the 475 range to the 350 m
Ω
range (RANGE 4).
30. Read the resistor using the 475 (RDGOHM?). Store as ACTUALRESISTANCE.
31. Calculate the Gain Calibration Factor (GCF) = EXPECTEDRESISTANCE /ACTUALRESISTANCE. Test this
factor to be 1.0, ±2%.
32. Send the Gain Calibration Factor (GCF) to the Model 475 (CALG 1,4,<GCF>).
33. Read the resistor using the 475 (RDGOHM?). Verify the reading to be EXPECTEDRESISTANCE ±0.01%.
34. Repeat steps 26 thru 33 for the 35 m
Ω
and 3.5 m
Ω
ranges (range 3 and 2) using the 30 m
Ω
and 4.3 m
Ω
resistors
respectively.
35. Send the Gain Calibration Factor (GCF) calculated for range 2 to range 1. The hardware gains for those two ranges
are equivalent.
36. Send the CALSAVE command to save the calibration constants into non-volatile memory.
8.11.2.2 Gaussmeter Calibration, 10 mA Excitation Ranges
This section describes the method of calibrating the 10 mA current source that may be used for future Hall sensors. The
five ranges of the 475 will need to be calibrated for each current setting. The highest range is for each current is
calibrated using a 33.2
Ω
resistor that is measured using the 3458 in a four lead resistance measurement mode. The
remaining ranges are calibrated by using the previous calibrated range as shown in the following steps.
1. Set the Gain Correction Factor to 1 for all five of the 10 mA hall current source ranges (CALG 2,1,1;CALG
2,2,1…).
2. Connect the 33.2
Ω
resistor to the DVM using a proper 4-lead connection.
3. Read the resistor using the DVM. Store as EXPECTEDRESISTANCE.
4. Connect a short across the Gaussmeter input of the Model 475 using a proper 4-lead connection.
5. Configure the 475 for 10 mA excitation current (HALLCS 2).
6. Configure the 475 for DC 5 digits (RDGMODE 1,3,1,1,1) on the 35
Ω
range (RANGE 5).
7. Zero the probe using the Zero Probe key or the ZPROBE command.
8. Connect the 33.2
Ω
resistor across the Gaussmeter input of the Model 475 using a proper 4-lead connection.
9. Configure the 475 for 10 mA excitation current (HALLCS 2).
10.
Read the resistor using the 475 (RDGOHM?). Store as ACTUALRESISTANCE.
11. Calculate the Gain Calibration Factor (GCF) = EXPECTEDRESISTANCE/ACTUALRESISTANCE. Test this
factor to be 1.0, ±3%.
12. Send the Gain Calibration Factor (GCF) to the Model 475 (CALG 2,5,<GCF>).
13. Read the resistor using the 475 (RDGOHM?). Verify the reading to be EXPECTEDRESISTANCE ±0.02%.
14. Connect the 3
Ω
resistor across the Gaussmeter input of the Model 475 using a proper 4-lead connection.
15. Configure the 475 for 10 mA excitation current (HALLCS 2).
16. Read the resistor using the 475 (RDGOHM?). Store as EXPECTEDRESISTANCE.