FD67 Profibus-DP Manual
37
LED designation
LED display
Behaviour
Status
U
A
Green
ok (> 18 V)
U
A
Red
Undervoltage or short-circuit
actuator supply
U
A
Off
No supply or
actuator supply < 12,5 V
♦
Table 7-5 : Status of the actuator supply on the bus node
7.2.2.1 Bus node response to faulty supply voltage
7.2.2.1.1 Short-circuit of sensor supply of internal system connection
A short-circuit at the socket or in the cable of the system connection is detected. The sensor supply, and
hence the module supply for this line, is switched off. The system goes over into communication error.
After the short-circuit has been rectified, the internal system connection can be restarted via a voltage
reset of the sensor supply. In case of inadequate power supply unit, it will be switched off before the
short-circuit detection by the bus node and will initiate a reset of the bus node. The U
S
LED on the bus
node is lit red for this line.
7.2.2.1.2 Short-circuit of actuator supply of internal system connection
A short-circuit at the socket or in the cable of the system connection is detected. The actuator supply for
this line is switched off. After the short-circuit has been rectified, it can be cleared via a voltage reset of
the actuator supply. The U
A
LED on the bus node is lit red for this line.
7.2.2.1.3 Undervoltage of sensor supply of internal system connection
Undervoltage is detected below approx. 17.0 V. The US displays of the lines affected are red. If the
voltage drops below approx. 12.5 V, the bus node goes into reset. The bus node reconnects to the
Profibus as soon as the sensor voltage rises above approx. 13.0 V.