Single-line opening

Purpose: To ensure that the DUT achieves the functional state defined in the specification when it is subjected to a rapid multi-line interrupt, for example, if the entire connector connected to the device under test is unplugged.

Test method: DUT operating modes 2.1 and 3.4 (i.e., test sleep mode and maximum load conditions), connect and operate the DUT as expected, interrupt the DUT connection, and then resume the connection, observe the performance of the device during and after the interrupt. For multi-connector devices, every possible connection should be tested.

The following test conditions should be met:

- Interruption time: (10±1)s

•Open circuit resistance: ≥10MΩ

2.10 Short Circuit/Overload Protection

Objective: To simulate the working conditions of short circuit and output overload of DUT

(10.1) Short circuit of signal line and load line

Test method: DUT operating mode 3.4 connects all relevant inputs and outputs (signal lines and load circuits) of the device under test to Usmax (see Tables 3 and 4) in sequence for a duration of 60 seconds ±10%, and grounded, as described in steps a) to steps f) below. Unless otherwise agreed by the customer and supplier, all other inputs and outputs remain open; perform steps a) to step f) on all signal lines/load circuits of the device under test

a) Connect the DUT signal line/load circuit to be tested to the Usmax

b) Maintain short circuit state with a duration of 60s±10%

c) Observe the behavior of the DUT during and after the holding time

d) Connect the DUT signal wire/load circuit to be tested to ground

e) Maintain a short circuit with a duration of 60s±10%

f) Observe the behavior of the DUT during and after the holding time in e).

Repeat steps a) to f) for all signal lines and load circuit inputs/outputs of the device under test.

For each of the following cases, the complete set of tests described above should be performed once:

Connecting the power supply voltage and ground terminal:

- Output on

- Output off

(10.2) Overload the load circuit

Test method: DUT working mode is 3.4, connect the DUT to the power supply, the load circuit should be able to operate normally.

Each load circuit should be tested individually:

-100% current capacity (nominal load)

-150% current capacity (overload)

For the test duration, the parameter specifications of the appropriate part of the ISO 8820 series (operating time rating) should be used, taking into account the upper tolerance plus 10%, and if protection other than fuses (e.g. electronic protection) is used, the test duration should be agreed by the customer and the supplier. This test is only applicable to systems/components with load circuits.

Purpose: To ensure the insulation withstand voltage of dielectrics. This test only requires systems/components that contain inductive components (e.g., relays, motors, wires) or connected to an inductive load circuit.

The overvoltage causes leakage current between DUT components through an electric field, which may have a negative impact on insulation performance. This test focuses on the insulation system and tests the ability of the insulating material to withstand high voltages generated by disconnecting inductive loads.

Test method: DUT working mode is 1.1 or 1.2, according to the requirements of ISO 16750-4:2023 5.6.2.2, 5.6.2.3 or 5.6.2.4, the damp heat cycling test used should be agreed by the customer and the supplier; After the damp heat cycling test, the system/component should be kept at room temperature for 0.5 hours, and the DUT should be applied 500V AC voltage (50Hz/60Hz) for 60s (other test voltages can also be accepted if the customer and supplier agree), and the applied voltage points are as follows:

•between the terminals with electrical insulation;

•Between the terminals with electrical insulation and the housing with electrically conductive surfaces;

•In the case of plastic housings, between the terminals and the electrodes that wrap the housing, such as metal foil.

2.12 Insulation resistance