Keithley 6485 - Limit Testing; Figure 8-1 Limit Tests; Figure 8-2 Limit Tests Example

8-2 Limit Tests Model 6485 Picoammeter Instruction Manual
Limit testing
As shown in Figure 8-1, there are two limit tests that can be performed on a DUT. Limit 1
is used as the wide pass band and Limit 2 is used as the narrow pass band. It is up to the
user to specify limits that conform to this pass band relationship.
Figure 8-1
Limit tests
Figure 8-2 shows an example where the HI and LO limits for limit 1 are ±2mA, and the Hi
and LO limits for limit 2 are ±1mΑ. A 0mA reading passes both limit 1 and limit 2 tests. A
+1.5mA reading passes limit 1 but fails limit 2. A +2.5mA reading fails both limit 1 and
limit 2.
Figure 8-2
Limit tests example
LO
LO
Limit
Limit
HI
HI
Limit
Limit
Limit 1 Test
(Wide Pass Band)
Limit 2 Test
(Narrow Pass Band)
Fail
Fail Fail
FailPass
Pass
-2mA
-1mA
LO Limit
LO Limit
+2mA
+1mA
HI Limit
HI Limit
Limit 1 Test
(Wide Pass Band)
Limit 2 Test
(Narrow Pass Band)
Fail
Fail Fail
FailPass
Pass