Valhalla Scientific 4314KV, Руководство по эксплуатации

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18
RESISTANCE ADJUSTMENTS
1. Select
200Ω
range.
2. Connect to a
100Ω
standard resistor.
Adjust R15 for a display reading equal to the value of the resistor.
3. Select
2kΩ r
ange and connect to
a 1kΩ
standard resistor.
Adjust RV1 for a display reading equal to the resistor value.
4. Select
20kΩ range
and connect to
a 10kΩ
standard resistor.
Adjust RV2 for a display reading equal to the resistor value.
5.
Select 200kΩ range and connect to a 100kΩ standard resistor.
Adjust RV3 for a display reading equal to the resistor value.
6.
Select 2MΩ range and connect to a 1MΩ standard resistor.
No adjust. Verify that display reading is within tolerance of the resistor value.
7.
Select 2Ω range and connect to a 1Ω standard resistor.
No adjust. Verify that display reading is within tolerance of the resistor value.
8.
If the 2Ω range is too low select R27 using the RC Box.
9.
Select 20Ω range and connect to a 10Ω standard resistor.
No adjust. Verify that display reading is within tolerance of the resistor value.
10.
If the 20Ω range is too low select R
37 using the RC Box.
IMPORTANT:
If it is necessary to perform step 4.8 or 4.10, go back and forth between the
2Ω, 20Ω and
200Ω range
s until all are in spec.
FAILSAFE CHECK
1. Connect the 3458A in the ammeter mode across the
current terminals.
Select the 2Ω range
.
2. Short out the cathode of D9 and the bottom pin or R44
(see image) and verify that the measured current is
equal or less then the value specified in the Fail Safe
current table.
3. Repeat this process for each range.
4.
For MΩ ranges it will be necessary to connect the
appropriate calibration resistor and measure the
voltage drop across it. Use Ohm’s Law to calculate the
failsafe current.
Range Fail-Safe Current
2Ω
8mA
20Ω
8mA
200Ω
1.8mA
2kΩ
180µA
20kΩ
18µA
200kΩ
1.8µA
2MΩ
180nA
Figure
7 – Fail-Safe shortin
g points