EM TEST
EFT 500 Series
Manual for Operation
V 2.00
14 / 21
3.5.
Computer setup for EFT/Burst testing.
During immunity tests high frequency interference is generated. Due to the length of the connected lines, a
certain part of this energy will be transformed into radiated interference.
Therefore the operator shall be aware that systems and installations in the neighborhood, even those not being
part of the test set-up can be disturbed.
Especially for fully automated test systems, where simple computers may be used, EMC problems within the test
system may occur. To avoid such disturbances in the following paragraphs some information is given to which
the operator has to taken care:
- EM TEST generators are tested with the maximum test level. If no damage has been occurred the equipment
must be seen as immune.
- The interference always will enter into a system at the weakest part. Within a computer controlled system the
weakest unit is almost the computer with its interconnection lines and the peripheral equipment.
- The most critical test concerning the above mentioned problems is the burst test according to IEC 1000-4-4.
This is a high frequency test, which may radiate extreme interference fields to the environment.
Concerning the test set-up the following points be explained:
1. The burst generator must be connected very good to the ground reference plane on the table.
2. The ground reference plane shall be connected to the protective earth system. For tests within a shielded
room the connection shall be made to the walls of the room.
3. The test set-up shall have one single ground reference point (not several)
GROUND LOOPS SHALL BE STRICTLY AVOIDED
4. The central ground reference point shall be located where the EFT generator is connected to the ground
reference plane. At the same point the reference ground plane shall be connected to the protective earth
system or to the shielded room.
