4. Troubleshooting (PROFIBUS DP)
♦ Causes of Error |
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| Possible Cause |
| Examination Method | Countermeasure |
| { Disconnected | (1) | Check that terminating | Fix the problem. |
| terminating resistors |
| resistors are connected to |
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| { Cable disconnection |
| both ends of the network. | How to find the trouble |
| { Disconnected | (2) | Measure resistance between | point: |
| connector |
| signal wires with device | Remove the terminating |
| { Disconnected signal |
| power supply OFF. | resistor on one end of the |
| wire | → Normal: 100 to 120 Ω | network. The trouble point | |
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| z Measuring point: Connection | is where resistance | |
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| of the trouble unit | changes from 220 Ω. | |
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| z For detail, refer to the section |
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| 4.2.3.1 Connection Problem. | Connect the connectors | |
| { Loose connector | Check for the connection of | ||
| { Loose signal wire | connectors and signal wires. | and signal wires again. | |
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| → The connectors and signal |
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| wires should be firmly |
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| connected. |
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| z Checkpoint: all stations and all |
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| branch taps |
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| z For details, refer to the section |
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| 4.2.3.2 Loose Connector and |
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| Signal Wire. | Take countermeasures | |
| { Noise | Check the noise intrusion via the | ||
| (external cause) | following paths (1) to (3). | against noise. | |
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| (1) | Noise via shield |
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| (2) | Induced noise via |
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| communication cable |
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| (3) | Device power supply |
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| → For details, refer to the section |
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| 4.2.3.3 Noise Intrusion. | Replace the unit with a | |
| { Broken unit | Replace the trouble unit with a | ||
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| new one. | new one. | |
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| → Verify whether the problem is |
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| fixed. |
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| z No cause is | Identify the trouble point by |
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| identified. | dividing the network. |
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| → For details, refer to the section |
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| 4.2.3.4 Broken Unit |
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| Examination. |
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Fieldbus I/O Rev.6 | 125 |
