Error handling and diagnostics 
 
Embedded PC  103 
CX1100-0002 power supply LEDs 
After switching on, the power supply immediately checks the connected Bus Terminal configuration. Error-free start-
up is signalled by the red "I/O ERR” LED being extinguished. 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. 
Display  LED  Meaning 
Power  Power supply  
The LED lights up green when the power supply is correct, but red if there is a short 
circuit. 
I/O 
Run 
K-Bus diagnostics  
The green LED lights up in order to indicate fault-free operation. "Fault-free" means 
that the communication with the fieldbus system is also running. 
 
I/O 
Error 
K-Bus diagnostics  
The red LED flashes to indicate an error. The red LED blinks with two different 
frequencies. 
 
The I/O error LED blink code 
Fast blinking  Start of the error code 
First slow sequence 
Error code 
Second slow sequence 
Error code argument 
 
LEDs for K-Bus diagnosis 
Error code 
Error code 
argument  Description  Remedy 
Persistent, 
continuous 
blinking 
  EMC problems  - Check power supply for overvoltage or 
undervoltage peaks 
- Implement EMC measures 
- If a K-Bus error is present, it can be 
localised by a restart of the power supply (by 
switching it off and then on again) 
0  EEPROM checksum error  Revert to the manufacturer’s setting 
1  Code buffer overflow  Insert fewer Bus Terminals. The programmed 
configuration has too many entries in the 
table 
1 pulse 
2  Unknown data type  Software update required for the power 
supply 
0  Programmed configuration 
has an incorrect table entry 
Check programmed configuration for 
correctness 
2 pulses 
n (n > 0)  Table comparison (Bus 
Terminal n) 
Incorrect table entry 
3 pulses 
0  K-Bus command error  - No Bus Terminal inserted 
- One of the Bus Terminals is defective; 
halve the number of Bus Terminals attached 
and check whether the error is still present 
with the remaining Bus Terminals. Repeat 
until the defective Bus Terminal is located. 
0  K-Bus data error, break 
behind the power supply 
Check whether the n+1 Bus Terminal is 
correctly connected; replace if necessary. 
4 pulses 
n  Break behind Bus Terminal 
n 
Check whether the Bus End Terminal 9010 is 
connected. 
5 pulses 
n  K-Bus error in register 
communication with Bus 
Terminal n 
Exchange the nth bus terminal