Diagnostic LEDs
After switching on, the Bus Coupler immediately checks the connected configuration. Error-free start-up is indicated when the red "I/O ERR" LED goes out. If the "I/O ERR" LED blinks, an error in the area of the terminals is indicated. The error code can be determined from the frequency and number of blinks. This permits rapid rectification of the error.
The Bus Coupler has two groups of LEDs for the display of status. The upper group with four LEDs indicates the status of the respective fieldbus. The significance of the "fieldbus status" LED is explained in the relevant sections of this manual - it conforms to conventional fieldbus displays.
On the upper right side of the Bus Couplers are two more green LEDs that indicate the supply voltage. The left LED indicates the presence of the 24 V supply for the Bus Coupler. The right LED indicates the presence of the supply to the power contacts.
Local errors
Two LEDs – the "I/O - LEDs" – below the above-mentioned Fieldbus Status LEDs display the operating states of the Bus Terminals and the connection to these Bus Terminals. The green LED lights up in order to indicate fault-free operation. The red LED blinks with two different frequencies in order to indicate an error. The error is encoded in the blink code in the following way:
Fast flashing | Start of the error code |
First slow sequence | Error code |
Second slow sequence | Error code argument |
Error code | Error code argument | Description |
|---|---|---|
1 pulse | 0 | EEPROM checksum error |
2 pulses | 0 | Programmed configuration |
3 pulses | 0 | Terminal bus command error |
4 pulses | 0 | Terminal bus data error |
5 pulses | n | Terminal bus error in register communication with terminal n |
6 pulses | 0 | Special fieldbus error |
The number of pulses in the first sequence indicates the error type, while the second sequence indicates the position of the last Bus Terminal before the fault. Passive Bus Terminals, such as a power feed terminal, are not included in the count.
In the case of some errors, rectification does not cause the Bus Coupler to leave the blink sequence. The operating state of the Bus Coupler remains "Stop". The Bus Coupler can only be re-started either by switching the power supply off and on again, or by a scanner reset.
Insertion and removal of Bus Terminals is only permitted when switched off. The electronics in the Bus Terminals and in the Bus Coupler are protected to a large measure against damage, but incorrect function and damage cannot be ruled out if they are plugged in under power.
The occurrence of a fault in the course of operation does not immediately trigger the display of error codes by the LEDs. The Bus Coupler must be requested to diagnose the Bus Terminals. The diagnostic request is generated at power-up or through an access by the fieldbus to the Bus Coupler. This means that if no data is being exchanged over DeviceNet when a Bus Terminal is removed from the system, the Bus Coupler will not necessarily report an error.