Fault tracing vacon • 38
24-hour support +358 (0)40 837 1150 • Email: vacon@vacon.com
7
7. FAULT TRACING
When an unusual operating condition is detected by the AC drive control diagnostics, the drive
initiates a notification visible, for example, on the keypad. The keypad will show the ordinal
number of the fault, the fault code and a short fault description.
The fault can be reset with the Reset button on the control keypad or via the I/O terminal. The
faults are stored in the Fault history menu which can be browsed. The different fault codes you
will find in the table below. This fault table presents only the faults related to the fieldbus in
use.
NOTE: When contacting distributor or factory because of a fault condition, always write down
all texts and codes on the keypad display and send a description of the problem together with
the
Drive Info File to fieldbus@vacon.com.
7.1 Typical fault conditions
Table 30. Typical fault conditions
7.2 RS-485 bus biasing
When none of the devices on the RS-485 bus is sending data all devices are in idle status. This
being the case, the bus voltage is in indefinte state, usually near 0 V due to the termination re-
sistors. This may cause problems in character reception because the single characters in se-
rial communcation begin with start bit referring to bus status '0' with voltage of less than -
200mV whereas the bus status '1' corresponds to bus voltage of more than +200mV. The RS-
485 standard considers the voltage interval -200mV...+200mV as undefined state. Bus biasing
is therefore needed to maintain the voltage in status ‘1’ (above +200mV) also between the mes-
sages.
To bias the bus you will have to add a separate active termination resistor specifically designed
for the RS-485 bus (e.g. Siemens active RS 485 terminating element (6ES7972-0DA00-0AA0)).
Fault condition Possible cause Remedy
Termination
resistor
Missing or excessive termination resistor.
Install termination resis-
tors at both ends of the
fieldbus line.
Cabling
• Supply or motor cables are located
too close to the fieldbus cable
• Wrong type of fieldbus cable
• Too long cabling
Grounding Inadequate grounding.
Ensure grounding in all
points on the net
Connections
Faulty connections.
• Excessive stripping of cables
• Conductors in wrong terminals
• Too loose connections of conductors
Parameter
• Faulty address
• Overlapping slave addresses
• Wrong baud rate
• Wrong control place selected
To Next Page
Loading...
