Verify that the four interlock DIP switches on the rack control unit (RCU) are enabled to ensure proper function of the ETX-1640x safety interlocks.

Refer to the Rack Control Unit section of the ATE Core Configurations Generation 2 User Manual for information about the location and settings of the RCU interlock DIP switches.

Figure 27. RCU Interlock DIP Switch

Refer to the following table for the default state of the interlock DIP switches in the ETX-1640x system.

Table 44. DIP Switch Default States
Switch State Position
1 Closed Up
2 Closed Up
3 Open Down
4 Closed Up
Important If all four DIP switches are Off (in the Down position), the interlock status is Closed.

Do not change the state of the RCU interlock DIP switches. Changing the state of the DIP switches compromises the ability of the test rack to deactivate hazardous signals.

To check the state of inputs to the interlock circuit, use the example program that NI provides. The example program can help determine whether the rack believes it is safe to source hazardous voltage. The program can also check whether the interlock circuit is behaving as expected.