Compliance Engineering Pty Ltd has expanded its EMC compliance testing capabilities to include EMC testing of vehicle sub components.
These expanded facilities will allow manufacturers of vehicle components to access EMC compliance measurements in accordance with the ISO 11452 series, ISO 7637 series and CISPR series of EMC standards.
Radio Frequency Immunity
RF immunity measurements can be performed using various methods depending on the standard and the frequency range. Some common methods of coupling the RF energy to the device are:
· TEM Cell
· Bulk Current Injection
· Direct Injection (via a capacitor or transformer)
· Free Field (Radiated from an antenna)
Stripline Method: The harness connected to the device is extended and positioned centrally between the septum and ground plane of the Stripline. This device can generate RF fields in excess of 200V/m with relatively low RF injected power levels.
Free Field Method (ALSE): The device and its extended harness are positioned over a ground plane. A radiating antenna is positioned 1 metre away from the device. Field levels of around 200V/m can be generated using a horn antenna over the frequency range of 200MHz to 1000MHz.
Bulk Current Injection Method: An Injection probe is positioned around the devices harness and RF energy is injected into the injection probe. This method is used in the frequency range of 1MHz to 400MHz with injected levels of up to 400mA (frequency dependent).
Radio Frequency Emissions
Conducted RF Emissions produced by the device and induced into the vehicles DC supply system on both the positive and negative lines are measured via 5 µH Line Impedance Stabilisation Networks (LISN’s).
Measurements of radiated RF emissions produced by the device and emitted through the air are performed over a metallic ground plane inside a fully anechoic RF shielded enclosure. The counterpoise of the Active Rod Antenna is bonded to the ground plane.
Conducted Transient Emissions produced when switching inductive loads on and off are measured using a Digital Storage Oscilloscope connected via a 5 µH LISN.
Transient emissions produced by devices in a vehicle may cause interference to other devices in the vehicle. These transients (Test Pulses 1, 2, 3a, 3b, 5 & 7) can be simulated and applied to devices to ensure immunity to interference when installed in the vehicle.
Electrostatic discharges are common events in vehicles, as occupants enter and exit a vehicle after travelling. These events can cause permanent damage to sensitive electronic circuitry.
Electrostatic discharges are applied to the electronic controls used in a vehicle electric seat. Discharge using a 150pF/330Ω network can be applied up to a voltage of ±30kV (Air Discharge method). Other discharge networks can be sourced depending on the particular requirement.