Earthing - ABB PFEA 111 User Manual

Tension Electronics PFEA111/112, User Manual
Chapter 2 Installation

2.4.3 Earthing

2-8
For trouble free operation, the earthing must be carried out carefully. Note the following:
• If the free (unscreened) length exceeds 0.1 m (4 in.) the individual pairs of power
and signal conductors must be twisted separately
• The external protective earth (PE) cable must be attached to one of the earthbar screw
clamps.
• All the cable screens have to be connected to the earth bar and the length of the screen
connection must be less than 50 mm (2 in.).
The cable screens must be earthed at one end only.
• Since the signal earth of the measurement system is connected to the chassis earth of the
tension electronics, the input of a superior system connected to the control system must not
be earthed. The best ways of interconnecting the measurement system and a superior
system to achieve optimal function are shown in
Figure 2-7. Connection to a superior system with an insulated or differential input
Figure 2-8. Connection to a superior system through a separate insulation amplifier
NOTE
Figure 2-7
PFEA111/112
0V
PFEA111/112
+
0V
-
and Figure 2-8.
+
-
0V
+
0V
3BSE029380R0101 Rev C