NORD Drivesystems BU0510 - Manual (Page 26)

POSICON position control for NORD frequency inverters, SK 530E and above
26 Subject to technical alterations BU 0510 GB-3911
3.2.2.5 Manual commissioning of the CANopen absolute encoder
In addition to "automatic" configuration (Auto) a "manual" setting (Manual) of the encoder is also possible. With
"Auto" the parameterisation is carried out by the frequency inverter. With manual commissioning, a CAN Bus
master is required in addition to the frequency inverter and the encoder. This must switch the encoder into the
bus status "Operational" and set the following parameters.
- Parameters 0x6001 and 0x6002: resolution, according to the settings in P605 "Absolute Encoder".
- Parameter 0x62000: cycle time. The parameterisation of a value ≤ 20ms is recommended. The
selected cycle time influences the reaction speed of the positioning control in the frequency encoder.
3.2.3 Encoder monitoring
If an absolute encoder is parameterised in the frequency inverter and the positioning control is enabled in
parameter P600 "Positioning Control", the function of the encoder is permanently monitored. Although the
encoder position is displayed when "Positioning Control" P600 is not enabled, no error messages are
generated in case of problems. Therefore emergency or manual operation is always possible.
In case of encoder error, the last valid position is retained in the frequency inverter.
If an absolute and an incremental encoder are present, the positioning difference between the two encoders
can be monitored with parameter P631 "Slip Error Abs/Inc". The maximum permissible deviation between the
absolute and the incremental encoder is specified by the value set in this parameter. With the value "0" slip
error monitoring is disabled. If the maximum permissible deviation is exceeded the error message "E013
(E14.6)" is activated. The gear ratio or the positions where the two encoders are installed may differ. For each
of the two encoders a parameter value for P607 "Speed Ratio", P608 "Reduction Ratio" and P609 "Offset
Position" can be set.
If there is no second, redundant encoder for position monitoring a slip error for the position can be specified
via the parameter P630 "Pos. Slip Error". In this case the current position is compared with the change in
position calculated from the current speed. On reaching a target position, the estimated position is set to the
actual position value of the encoder in order to prevent addition of errors over time. If the positioning difference
exceeds the slip error value set in P630 "Pos. Slip Error", the error message "Error E013 (E14.5)" is activated.
For larger travel paths larger values are necessary in P630. The necessary value is best determined by
experiment. With the value "0" slip error monitoring is disabled.
The permissible operating range can be restricted with the parameters P616 "Minimum Position" and P615
"Maximum Position". If the drive unit departs from the permissible range, the error message "Error E013
(E14.7) maximum position exceeded" or "Error E013 (E14.8) minimum position undershot" is activated.
With a set value of "0" the relevant position monitoring is disabled. In parameter P604 "Encoder Type", setting
3, 4, 5 or 7 the position monitoring is also not enabled.
NOTE
Position setpoint values which are greater than the set value for "Minimum Position" in
parameter P616 and "Maximum Position" in parameter P615 will be internally limited to these
set values in the inverter.