4. Troubleshooting (DeviceNet)
Countermeasure 2: Disconnect the shield wire to isolate it from the ground.
When noise intrudes the ground line because a noise source such as an inverter is installed near the communications power supply, disconnect the shield wire of the communication cable and isolate it from the ground to restrain noise intrusion.
Power Supply Tap
V+ | V+ |
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CAN H | CAN H |
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Shield (S) | Shield (S) | DeviceNet cable |
CAN L | CAN L |
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V- | V- |
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V+ V- S
Disconnect here.
V+ V- FG
Ground 100 Ω or less.
Communications
Power Supply
24 V DC
♦Induced noise via communication cable
Separate the DeviceNet signal wire from the other wires (especially power wires).
* Separate the signal wire from the power wires 300 mm or more.
| Light electrical cable | Suspended ducts | Floor ducts | ||||||
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PLC input/output wire |
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PLC power wire |
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Control circuit wire |
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| Power cable |
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Power wire
During site inspection, bypass the wire that is possibly affected by induced noise with other cables and then lay the cables. Establish the communication under no induced noise condition and verify whether an error occurs.
102 | Fieldbus I/O Rev.6 |
