The ETX-1620x includes an interlock system to prevent devices from outputting hazardous voltage except under controlled conditions.

The interlock circuit checks four conditions before allowing the output of hazardous voltages. All interlocks are dry contact and the default state is Open. The following table describes requirements for closing each interlock.

Table 32. Requirements for Closing Interlocks
Condition Name CLOSED Condition Interlock Control Pins on the Mass Interconnect
Adapter Detect The Adapeter_Detect+ pin is pulled low (for example, through Adapter_Detect-).

J1 A33 (Adapter_Detect+)

J1 A34 (Adapter_Detect-)
HV Enable The HV_Enable+ pin is pulled low (for example, through HV_Enable-).

J1 C33 (HV_Enable+)

J1 C34 (HV_Enable-)
Isolation Interlock Output of high-power supply is isolated from ground. N/A
Door Interlock The front door, rear door, and both side panels are closed. N/A

If all four conditions are met, the interlock circuit is closed.

If any of the four conditions are not met, the interlock circuit is open. When the circuit is open, the pulser does not allow you to build a path, and no voltage passes from the bias supply to the mass interconnect. In addition, the high-power supply does not allow any output.

Adapter Detect Interlock

The Adapter Detect interlock is intended to be used to indicate whether an adapter is plugged into the mass interconnect.

On J1, hardwire pins A33 and A34 together in the adapter to optimize how the interlock circuit checks the Adapter Detect condition. For example, if you hardwire J1, A33 and A34 together in the adapter, Adapter Detect is pulled low whenever the adapter is plugged into the system.

The Adapter Detect interlock also interacts with the EMO_MEASURE circuit. Refer to Configuring EMO Measure for more information.

HV Enable Interlock

The HV Enable interlock is intended to be actively controlled by the adapter. The HV Enable interlock opens or closes as conditions in the adapter or assembly line demand.

Note Do not actuate the HV Enable interlock individually for each DUT. The interlock circuit has an expected life of about 500,000 actuations.

For example, if you connect the HV Enable interlock pins to a programmable logic controller (PLC) inside the adapter, the PLC controls whether the pins are shorted together based on whether it is acceptable to allow hazardous voltage outputs from the test system.

DIP Switches

Verify that the four interlock DIP switches on the rack control unit (RCU) are enabled to ensure proper function of the ETX-1620x 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.

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.