Keithley 7999-4, Instruction Manual

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Service Information 4-3
Performance verification
The following paragraphs discuss performance verification procedures for the Model 7999-4
including a channel resistance verification procedure.
CAUTION Contamination will degrade the performance of the switch. To avoid
contamination, always grasp the switch by the cover; do not touch the
connectors.
NOTE Failure of any performance verification test may indicate that the microwave switch
is contaminated. See “Handling and cleaning precautions” earlier in this section for
information on cleaning the switch.
Environmental conditions
All verification measurements should be made at an ambient temperature between 18˚ and
28˚C, and at a relative humidity of less than 70%.
Recommended equipment
Table 4-1 summarizes the equipment necessary for performance verification (channel resis-
tance tests).
Channel resistance tests
Perform the following steps to verify that the relays contact is closing properly, the relay
resistance is within specification, and that the relay opens properly.
1. Turn on the Model 2010 DMM, and allow it to warm up for one hour before making
measurements.
2. Set the Model 2010 to the 10
Ω
range, and connect the four test leads to the INPUT and
SENSE
Ω
4 WIRE jacks.
3. Short the free ends of the four test leads together, and enable REL on the Model 2010 to
null out residual resistance. Leave REL enabled for the entire test.
Table 4-1
Recommended verification equipment
Manufacturer/Model Equipment Description Specifications
Keithley 2010 Digital Multimeter 10
Ω
range, 60ppm
Keithley 1681 Test Lead Sets (2) Banana plug/clips