Key Points for Noise Reduction

Our robot controller and Manipulator is a product designed with the premise of being incorporated into mechanical devices. The EMC compatibility of mechanical devices, that has our products incorporated into them, changes depending on the structure of the device, wiring, and positioning in the customer’s environment. Therefore, evaluation of the EMC compatibility as a final product should be done by the customer.
Below describes things to be careful about regarding the structure, wiring, and location of the device, in order to not be affected by noise as possible or not cause them at all.

AC Power Cable

• The power supply must be grounded to a class D ground (grounding resistance of 100 Ω or less).
  Grounding of the Controller frame is important not only for the purpose of preventing electric shock, but also to reduce the effects of electrical disturbances from the surrounding area. The ground wire (green/yellow) of the Controller power cable must be connected to the ground terminal of the power distribution system.

• Power should be supplied as far as possible away from power lines connected to equipment which may be a source of noise.

• If the Controller and single-phase AC motor are powered from the same power line, change the phase.

• Power lines should be twisted pair.

• AC and DC lines should be housed in different ducts and as far apart as possible.
  For example, AC motor power lines and Controller power lines should be as far away as possible from I/O lines for devices such as sensors and valves, and both should not be bundled together with cable ties.
  If the lines are crossed, they should be crossed perpendicularly.
  

  Symbol	Description
  a	Dedicated AC line duct
  b	Keep as far apart as possible
  c	Dedicated DC line duct

Communication Signal Cables

• Make sure to always use cables with shields for communication signal cables such as I/O, safety I/O, USB, Ethernet, RS-232C, and fieldbus, and keep them as far away as possible from noise sources in the surrounding area.

• When using inductive load components such as relays and solenoid valves for Controller I/O, use components that have noise protection.
  If the component is not protected from noise, be sure to attach a diode or other noise-protection component immediately before the inductive load. Select noise protection components that match the withstand voltage and current according to the inductive load.

• For AC motors such as conveyors (induction motors, 3-phase induction motors, etc.), be sure to insert a spark suppressor between the wires when starting, switching forward/reverse rotation, and so on.
  Putting it between the lines and as close as possible to the motor will also increase its effectiveness.

• The following EMC measures should be implemented for the MC cable, and each communication cable (Ethernet, fieldbus, etc.) if necessary. Below are some examples:

  • Lead wire countermeasure example
    Partially remove the external cover of the cable near the connector and let the shield be revealed.
    Reveal the shield near the connector as possible.
    Ground the part of the shield that is revealed and the chassis with a lead wire.
    Use lead wires that is less than 5 cm.
    When performing grounding, do so near the connector rather than the strain relief side.
    

  Symbol	Description
  a	Connector side
  b	Crimp terminal
  c	lead wire (5cm or less)
  d	Shielded cable
  e	Strain relief side

  • Clamp countermeasure example
    Partially remove the external cover of the cable near the connector and let the shield be revealed.
    Reveal the shield near the connector as possible.
    Put the part of the shield that is revealed between the conductivity clamp and secure it to the chassis with a screw.
    Implementing on both sides of the cable enhances the effect.

  

  Symbol	Description
  a	Seiwa Electric earth clamp (E0808A, E0817AD)
  b	Screw into the Controller and ground it

  • Ferrite core countermeasure example
    Insert the ferrite core near the connector as possible.
    If necessary, increase the number of turn when inserting the ferrite core. Implementing on both sides of the cable enhances the effect.

  

  Symbol	Description	Countermeasure Cables
  a	Kitagawa industry: GTFC-41-27-16	Fieldbus, LAN
  	Kitagawa industry: RFC-20 Kitagawa industry: MRFC-13 Takeuchi industry: NFT-20-20DK	MC power
  	Kitagawa industry: NRFC-6 Kitagawa industry: MRFC-8 Takeuchi industry: NFT-8	MC signal

Manipulator

• To secure the Manipulator to the base table, refer to the following:
  “Manipulator Manual” -Base table
• Ground one or multiple parts of the base table with a lead wire.
  Use short lead wires as much as possible.