4. Troubleshooting (DeviceNet)
(2)Separate each slave from the network
Check for each slave. The trouble point is where error condition changes into normal condition.
Master PLC
Terminating
Resistor
Branch Tap | Branch Tap |
|
|
| Slave | Slave | Slave |
Communications |
| Slave | |
Power Supply | Terminating |
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|
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| |
| Resistor | Second First |
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Separate slaves one by one from the network.
4.1.3.5 Network Configuration and Specifications
(1)Maximum Network Length and Drop Line Length
Check that the cables used on the network meet the following specifications.
Type | Baud Rate | Max. Network | Drop Line | Total Drop | |
Length | Length | Line Length | |||
|
| ||||
Thick Cable | 500 kbps | 100 m |
| 39 m | |
| 250 kbps | 250 m |
| 78 m | |
| 125 kbps | 500 m | 6 m | 156 m | |
Thin Cable | 500 kbps | 100 m | 39 m | ||
| |||||
| 250 kbps | 100 m |
| 78 m | |
| 125 kbps | 100 m |
| 156 m |
(2)Terminating Resistor
Ensure that two terminating resistors are connected to both ends of the network (trunk line). The terminating resistor should be 121 Ω 1/4 W.
(3)Cable and Branch Tap
The cables and branch taps should meet the DeviceNet specifications.
(4)Communications Power Supply
The communications power supply should be dedicated to DeviceNet.
Do not share power source with the communications power supply and I/O device. *
*Noise due to load on/off may affect DeviceNet communications via the communications power supply.
(The noise causes remote I/O communication error, Busoff detection, and broken unit.)
Fieldbus I/O Rev.6 | 105 |
