Programming instructions

48 Chapter 4 Performance Verification Tests
4-Wire Ohms
Function Offset Test
(Rear Terminals)
This procedure performance verifies the rear terminal ohms offset.
1. Connect a low thermal short across the rear terminals of the
3458A as shown for the front terminals in Figure 1 on page 23.
2. On the 3458A under test, select 4-wire ohms and the 10 Ω range by
executing OHMF, 10.
3. Execute Trig and use the OHMS TESTS Test Card to record the offset
reading.
4. Remove the short from the rear panel input terminals.
4-Wire Ohms
Function Gain Test
The following is a step-by-step procedure for all test points that performance
verify gain of the ohms function. The procedure requires alternately
connecting the transfer standard DMM and then the 3458A under test to the
resistance verification source as described in the section titled "General Test
Procedure".
1. Connect the resistance standard to the transfer standard DMM 4-wire
ohms front input terminals.
2. Set the range of the transfer standard DMM as specified in Table 6.
3. Set the range of the 3458A under test as specified in Table 6.
4. Set the resistance standard to the ohms level specified in Table 6.
5. Execute Trig and read the output of the resistance standard as
measured with the transfer standard DMM and record this reading in
the "Transfer Standard Reading" column of the OHMS TESTS Test
Card.
6. Remove the connection from the transfer standard DMM to the
resistance standard.
7. Connect the resistance standard to the front panel 4-wire ohms input
terminals of the 3458A under test.
8. Execute Trig two times and read the value as measured with the
3458A under test and record this value in the "Unit Under Test
Reading" column of the OHMS TESTS Test Card.
9. Repeat steps 1 through 8 for each of the remaining resistance test
points as specified in Table 6.