Appendix A.Configuration Example ALSPA PROFIBUS Field Bus Coupler
Page A8
Technical Manual
(09/06)
Note that the data will be displayed un-scaled and in decimal. The
drive may limit data before writing it into a parameter if it exceeds
that parameter’s limits, see Section 7.4.11.
A.11
Check For Data Errors
Once the drive has been configured the user should check that no
data errors are occurring. Data errors can occur when the
PROFIBUS module attempts to write the data from the PPO into
drive parameters. This may be because the parameter is not able to
accept data in this manner, or because the data itself is outside
accepted limits. Data errors are given in P75.42 to P75.45. For the
receive and transmit PPO packets there is an error code of the last
error that occurred and the number that have occurred since the
last PROFIBUS configuration attempt. The list of data error codes
and their meaning is given in Section 7.4.11. An example for the
source data is given in Table A-12 below.
Table A-12 Data error example
Parameter
Value
Meaning
P75.44
200H
Read access from a parameter was
denied
P75.45
20
20 errors have occurred since the
last PROFIBUS link configuration.
In this example read access to a parameter was denied, possibly
because that parameter does not exist. This implies that one of the
parameters set for source is incorrect and does not actually exist.
A.12 Fallback
Values
The example declares a PROFIBUS reference and a PROFIBUS
control word, both of which have the option of a fallback value. A
fallback value is a value that will be used instead of the PROFIBUS
value if the PROFIBUS link becomes unhealthy. As a simple
example, if the PROFIBUS link is lost then the user may want to
force the speed reference to zero. To use this feature the
PROFIBUS link first needs to be configured to select fallback value
