Key Points for Noise Reduction
Pay attention to the following points when wiring to minimize the effect of noise.
The power supply must be grounded to a class D ground (grounding resistance of 100 Ω or less). Grounding of the Manipulator frame is important not only for the purpose of preventing an electric shock, but also to reduce the effects of electrical disturbances from the surrounding area. The ground wire (green/yellow) of the Manipulator’s power cable must be connected to the ground terminal of the power distribution system. For details about the plug and the Manipulator’s AC power cable, refer to the following.
Power supplyPower should be supplied as far as possible away from power lines connected to equipment which may be a source of noise.
AC and DC lines should be housed in different ducts and as far apart as possible. For example, AC motor power lines and Manipulator power lines should be as far away as possible from I/O cables 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 |
Keep wiring to I/O connectors and EMERGENCY connectors as short as possible. Be sure to use shielded wires, and clamp the shield inside the connector. Also, keep as far away as possible from noise sources in the surrounding area.
When using inductive load components such as relays and solenoid valves for Manipulator 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.
Communication cables such as USB, Ethernet, and fieldbus are susceptible to noise. Therefore, keep them as far away as possible from noise sources in the surrounding area.
The following EMC measures should be implemented for the Fieldbus I/O cables as needed.
- Ground the cable shield section.
Symbol Description a Remove outer sheath and affix with an FG clamp b Screw into the Controller and ground it - Attach ferrite core to cable.
Symbol Description a Ferrite core