Solar Electronics Line Impedance Stabilization Networks (LISNs)

The purpose of ISO 7637-2 is to ensure electromagnetic compatibility of passenger and commercial vehicles operating on 12V or 24V electrical systems. ISO 7637-2 requires multiple conducted transients to be coupled onto DC lines to test the compatibility of vehicles. This standard is applicable to both internal combustion engine and electric motor vehicles.   Equipment Required: Transient Generator - HILO CAR TEST 14 Oscilloscope - Tektronix MDO4104C Differential Probe - Probe Master 4234 ISO 7637-2 Test Pulses The following tables show data that highlights Pulse 1, Pulse 2a, Pulse 2b, Pulse 3a, and Pulse 3b. Pulse 1 ISO 7637-2 Pulse 1 is used to simulate the transients created in the case that a motor, or inductive load, is disconnected from the circuit.    Parameters of this pulse can be verified using an oscilloscope and differential probe to meet the specifications below. Pulse 2a ISO 7637-2 Pulse 2a is used to simulate transients that occur when there is a current interruption on a device in parallel with the DUT and caused by the wiring harness inductance. Pulse 2b ISO 7637-2 Pulse 2b is used to simulate transients when a vehicle is turned off, but electric DC motors remain active and serve as a generator. Pulse 3a The pulse 3a is similar to an EFT pulse as seen in IEC 61000-4-4 (HYPERLINK THIS), this transient waveform is simulating switching occuring in a system connected by a wiring harness, in which the load is capacitive or inductive. Pulse 3b Similar to pulse 3a, except opposite polarity. Pulse 3b is another EFT waveform representing switching within a wire harness. These pulses also simulate the scenario in which a fuse is blown.   Pulse 4, 5a, & 5b ISO 7637 Pulse 4, Pulse 5a/5b were removed from the most recent revision of ISO 7637-2 and can be found now in ISO 16750-2.   ISO 7637-2 Test Equipment ATEC recommends the following products for testing