General information and networking
1.2 Application planning
1.2.1.2
Grounding concept
Components
The SINUMERIK 840D sl system consists of a number of individual components which have
been designed so that the system complies with the appropriate EMC and safety standards.
The individual system components are:
● Numerical Control Unit (NCU)
● Machine Control Panel (MCP), Machine Pushbutton Panel (MPP)
● Keyboard
● Operator panels (operator panel front + TCU/PCU)
● Distributor box and handheld unit
● S7-300 I/O with IM 153 interface module
Grounding measures
The individual modules are attached to a metal cabinet panel. Insulating paints on the mounting
points (e.g. tension jacks) must be removed.
It is permissible to cluster the operator control components regarding connection/potential
bonding.
Example: The control panel on the swivel arm.
It is sufficient in this instance to connect the ground connections of, for example, the PCU,
TCU, and operator panel front using a cable and to route a shared grounding conductor to the
central ground connection in the control cabinet.
Additional references
EMC Design Guidelines
1.2.1.3
EMC compatibility
In addition to the protective grounding of system components, special precautions must be
taken to guarantee safe, trouble-free operation of the system. These measures include
shielded signal lines, special equipotential bonding connections, and isolation and shielding
measures.
Shielded signal cables
● For safe and fault-free operation of the system, the specified cables must be used.
● For digital signal transmission, the shield must have a conductive connection at both sides
of the housing.
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Operator panel front: OP 012
Manual, 09/2016, A5E36371591B