AVL F-FEM-DDC User Manual

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Installation
F-FEM-DDC — User’s Guide
3.3.4 Grounding and Shielding
3.3.4.1 Grounding
The grounding concept consists of following aspects:
 At electrically leading sections no dangerous contact voltage ought to be.
 Interference currents are to be retourned to the interference source the
shortest possible way.
There is a demand for a small resistance to earth, considering the rules of high
frequence technique, concerning layout, current conductor profile and
contacting.
In the F-FEM-DDC the digital and analog ground of the circuit is connected to the
metal case. The case should be connected to the ground of the engine in the test
cell with a low inductive Cu-band. If a cluster of FEMs exists, these also should
be connected to each other with a ground braid. PE wire is carried along voltage
supply.
If several FEM clusters are connected with each other in a network, every cluster
should be grounded with low inductance to the ground of its local signal source.
If a IEEE1394 interface is used, ground wires should be used between the indi-
vidual FEM clusters as well as between the first cluster and the host system
(PUMA test bed workstation). The equipotential bonding is ensured over the PE
wire, which is carried along power supply.
The ground wires minimise the effects of the ground loop between the different
ground potentials of the network.
In this case, a compensatory current over the ground wires and over the supply
wire shielding is possible.
In the case that the ground of the engine in the test cell and that of the host
system have to be separated (e.g. due to too much distance or ground loops) the
FEM cluster which is assigned to the engine in the test cell should have its own
24 V power supply. Then the shielding of the power supply lines of the FEM
cluster must be connected via a capacitor to the same PE to which the 24 V
power supply is connected. The ground wire must then be clamped to the 0 V
output of the 24 V power supply.
Information
 Avoid causing any mechanical stress to the IEEE1394 cables!
 While working on the cable, note that pulling forces greater than 50 N can
damage it!
 If you use wire straps, do not squeeze the cables or pinch them off. Fasten
the wire straps carefully!
 All cable connectors must be fastened to the F-FEM housing with
screw-type locking.
 The IEEE1394 cables must not be cut off or elongated by soldering!
Repeaters must be used instead!
 A harmed cable is permanently damaged and must be replaced with a new
one!
Information
The 24 V supply of the F-FEM-DDC is isolated.

AVL F-FEM-DDC Specifications

General

Brand	AVL
Model	F-FEM-DDC
Category	Measuring Instruments
Language	English