Service manual

Test 2-2:
DC Isolation Test
This test verifies that sufficient DC isolation exists at various points on the
Module. DC Isolation is checked from NO to NC, NO to Chassis, and NC to
Chassis. This test uses the test fixture (see Figure 2-1).
NOTE
The DMM used should be capable of measuring at least 1 G
Ω.. If the
DMM indicates an overload, record the reading as >Rmax, where Rmax is
the highest resistance that the DMM can measure. For example, if the
DMM is an Agilent 3458A, a typical return for an overload is 1.E+38 and
the entry in Table 2-1 should be >1.2 G
Ω..
NC (&C) to NO Isolation 1. Make hardware connections as shown in Figure 2-4
2. Set DMM to 2-wire ohms, 1 G Ω range
3. Send *RST to Module
4. Trigger the DMM with TRIG SGL
5.
Record the DMM reading in Table 2-1 (NC to NO)
Figure 2-4. NC to NO Isolation
28 Verification Tests Chapter 2