Siemens S5-135U/155U - Manual (Page 56)

3-30
System Manual
C79000-G8576-C199-06
3.6 Interference-Free Connection of Monitors
These sections cover the following topics:
S
Floating connection of cables at video inputs
S
Shielding and grounding concept
Information on selecting the components can be found in Catalog ST80.
3.6.1 Interference-Free Connection of a Monitor to the CP of the S5
Controller
Operator control and process monitoring systems from the COROS product
family can be used with monitor connections. The physical arrangement of
apparatus and the interference level of the environment are important for the
interference-free connection of monitors to SIMATIC S5 control systems.
The choice of monitor and video cables is governed by the following:
S
Whether the monitor and PLC are to be operated under low-interference
conditions or
S
under industrial conditions.
Where the monitor and PLC are installed under low-interference
environmental conditions and operated over short distances, the monitor and
PLC are at almost the same ground potentials. Interference and ground loop
disturbances are therefore not expected.
In these cases, you can drive the monitor both via TTL signals and via analog
signals. Digital cables or single-shielded coaxial cables can be used to
transmit the video signals. Note that the braided shield of the coaxial cable
serves as the return conductor and must not be connected to the shield bar.
The monitor and communication processor (CP) are interconnected without
additional shielding and grounding.
Where the monitor and PLC are installed under harsh industrial conditions
and operated over great distances, the devices may be at different ground
potentials. These different ground potentials may cause interference and
ground loop disturbances.
Operation of the
Monitor and PLC
under
Low-Interference
Conditions
Operation of the
Monitor and PLC
under Industrial
Conditions
Installation Guidelines