6. Trouble Shooting
SMC CORPORATION
MOD/NET LED | Cause & Countermeasure |
Lights off | PWR LED lights off |
| <Countermeasure> |
| Confirm that power for SI unit circuit is supplied. |
| Confirm correct wiring. |
| If above countermeasures do not improve status, please exchange SI unit. |
| PWR LED lights up |
| <Countermeasure> |
| Confirm that baud rate is set correctly. |
| If MOD/NET LED lights off in spite of baud rate is set correctly, change SI unit. |
Green flashing | Connection waiting |
| Shows communication waiting status between SI unit and master. |
| <Countermeasure> |
| Confirm master operate correctly. |
| If using scan list, ensure slave is recorded to scan list correctly. |
Red flashing | Communication wire disconnected error |
| <Countermeasure> |
| Confirm communication wire is not disconnected. |
| <Remark> |
| Red flashing if master power source is turned off during communication. |
Red lights up | Node address overlapping error |
| <Countermeasure> |
| Confirm there is no overlapping on the node address. |
| BUS OFF error |
| Detects communication error. |
| <Countermeasure> |
| Case 1 |
| Communication error due to noise. |
| Confirm there is no component or high voltage cable that generate noise |
| around communication wire. |
| Make some distances between communication wire and noise source. |
| Case2 |
| Communication cable problem. |
| Confirm terminal resistance (121ohm) connects to the both ends of |
| communication wire that is main wire of communication wire. |
| If red MOD/NET LED is still lights up in spite of above countermeasures, |
| change SI unit. |
CAUTION
When red MOD/NET LED is lit, even if cause is solved, SI unit do not do
SI unit isn’t available for monitoring of power supply for solved valve.
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