EMC-compliant installation

Electromagnetic compatibility (EMC) is understood as the ability of an electrical unit to function without faults in a given electromagnetic environment without being influenced by the environment or without influencing the environment in an impermissible manner.

Possible malfunctions

Electromagnetic interference may interfere with your controller in different ways:

  • Electromagnetic fields
  • I/O signal cable
  • Bus system

Ensuring EMC

Adhere to the following rules to ensure EMC:

  • When installing the modules, ensure that any inactive metal components are grounded via a proper large-surface earth.
    • Provide a wide area metal-on-metal contact between the unit housing and ground.
    • Establish a central connection between ground and the earthing/PE system.
    • If possible, do not use any aluminum components.
  • Ensure that wiring is routed properly during installation.
    • Route power cables (power current, current supply) and signal cables in separate cable ducts.
    • Route signal cables as close as possible to ground surfaces (e.g. frames, metal rails, sheet metal, etc.).
  • Ensure that the shielding of lines is routed and mounted properly.
    • Signal cables must always be shielded.
    • Signal cables with analog signals must always be shielded. If low-amplitude signals are transferred, it may be advantageous to connect the shield on one side of the cable only.
    • Attach the shields of cables in the control cabinet over a large surface area to the shield bus/PE rail. Secure the line shields using cable clamps.
    • Ensure that the shield bus/PE rail has a low-impedance connection to the control cabinet.
    • Use metallic or metalized plug connector housings for shielded signal cables.
  • Use LEDs for illumination inside control cabinets. Do not use fluorescent lamps.
  • Use special EMC measures for special applications.
  • Consider using quenching circuits for inductances.
  • Create a single reference potential and ground all electrical equipment wherever possible.
    • Ensure that earthing measures are implemented effectively.
    • Provide a star-shaped connection between system components and control cabinets of the MOVI-PLC® I/O system C and the ground/PE system. This will prevent ground loops.
    • Where potential differences exist, you must install sufficiently large equipotential bonding conductors between the different parts of the system and control cabinets.