BECKHOFF BC2000 - Manual (Page 15)

Basic Principles
BC2000 14
PLC LED If the PLC LED lights, the program has started on the BC2000. The LED
flashes while a boot project is being created.
Diagnostic LEDs on the
BC2000
CYC
ERR
WD
PLC
The bus terminal controller interrogates the configuration of the bus
terminals after it has been switched on, then performs exchange of data
with the terminals. This means that the red I/O LED goes out after a fault-
free start-up, and the green I/O LED lights. The green I/O-LED lights with
the PLC timing on the bus terminal controller. If no program is running on
the BC2000, the pre-set cycle time for triggering the terminal bus is used.
CYC ERR WD Meaning Remedy
lit off lit Telegrams are passing cyclically along
the ring
Inputs are read and outputs are set. Everything is satisfactory
lit off lit I/O-RUN flashes The PLC cycle time that has been
set is too long > 100 ms
lit off off The ring is functioning, but the bus
terminal
controller is not being
addressed
Re-examine the control software
or the assignment list
blinking off off The controller only occasionally
accesses the bus. The outputs drop
away.
Re-examine the control software
off lit off (Physical) bus fault, faulty telegrams are
circulating in the ring, e.g. optical fibre
damaged, previous module faulty, plug
not properly inserted Check:
- whether the optical fibre cable is
inserted
- whether the optical fibre cable is
broken
- whether previous module is
ready for operation
off blinking off Occasional CRC error (green I/O LED
lights)
Inputs are read; outputs are not
updated; Optical fibre connection damaged
off off off No operating voltage, serious fault, no
function - Electrical power supply