BECKHOFF BK7500 - Manual (Page 17)

Basic information
BK7500 17
Starting operation and diagnostics
After switching on, the bus coupler immediately checks the connected
configuration. Error-free start-up is signalled by extinction of the red LED
“I/O ERR“. 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.
You will find a detailed description in the chapter entitled "The diagnostic
LEDs".
The diagnostic LEDs 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 field bus.
The significance of the “field bus status“ LED is explained in the relevant
sections of this manual - it conforms to conventional field bus displays.
On the upper right hand side of the bus couplers are two more green LEDs
that indicate the supply voltage. The left hand LED indicates the 24 V
supply of the bus coupler. The right hand LED signals the supply to the
power contacts.
Local errors Two LEDs, the “I/O” LEDs, in the area below the field bus status LEDs
referred to above, serve to indicate the operating status of the bus
terminals and the connections to these terminals. The green LED lights up
in order to indicate fault-free operation, where “error-free” implies that
communication with the fieldbus system is also operating correctly. The red
LED blinks with two different frequencies in order to indicate an error. The
error is encoded in the blinks as follows:
Rapid flashing Start of the error code
First slow sequence Type of error
Code of flashes
Second slow sequence Location of error
Location of error
The number of flashes corresponds to the position of the last bus terminal
before the error, not counting passive bus terminals such as power input
terminals.
The bus coupler will carry on flashing the error code even when you have
cleared the fault and its operating mode will remain at "Stop”. The only way
to restart the bus coupler is by switching the power supply off and on
again.