Lenze i950 Series, Руководство пользователя

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12.1.3.4 Evaluation of the signal quality
Signal quality
The signal quality is evaluated by the
0x2C42:004 parameter, which is used to monitor the
initial read-out and setting of the position.
If a transmission error should occur:
•
The current angular drift is marked as invalid in parameter , bit 7
•
The inverter maintains its operating status
Angular drift
Communication with the encoder is no longer monitored during angular drift
determination.
The value displayed in 0x2C42:003 is determined in different ways depending on the type of
encoder:
•
Determination of the current angular drift for the SinCos encoder
In the case of an incremental SinCos encoder, the pulses between two zero pulse events of
the Z-track are counted. Assuming that there are no faults, this value corresponds to the
set number of increments. The accuracy of this process corresponds to ± 1 increment grad-
uation of the encoder, with the difference between the set number of increments and the
counted pulses being converted to an angle with an accuracy of ±0.1°. The disadvantage is
that an updated angular drift value only become available at the end of a complete
encoder revolution. In turn, this means that the update rate depends on the speed.
•
Determination of the current angular drift for the SinCos Hiperface® absolute value
encoder
In the case of a SinCos absolute value encoder with HIPERFACE® protocol, no Z-track is
available; instead, the position is regularly read out of the encoder. When the first encoder
read-out operation is performed (after power-up or elimination of wire breakage), the
encoder position is used to initialise the internal device counter unit and to set an internal
device position. All other read-out processes from the encoder are used to generate a dif-
ference between the internal device position and the encoder position. Assuming that
there are no faults, the difference is zero. However, the dead time of the communication
with the encoder means that the accuracy of the process is dependent on the speed and
therefore restricted compared to the zero pulse process. However, the advantage is that
the update rate does not depend on the speed, but is instead only determined by the com-
munication rate. The update rate is encoder-specific and is generally in the range between
30 ... 50 ms.
Parameter
Address Name / setting range / [default setting] Info
0x2C42:003 Encoder settings: Angle drift
•
Read only: x.x °
Display of the angular drift of the current angle error.
This indicates whether too many or two few pulses have been detected
by the internal device counter unit for EMC-related reasons.
0x2C42:004 Encoder settings: Actual amplitude signal quality
•
Read only: x %
The signal quality indicates the actual amplitude of the SinCos analog
signals with regard to 1 Vss = 100 %.
•
The signal quality should be between 95 ... 105 %.
•
There is no need for optimisation if the signal quality is within the tol-
erance zone for the analog encoder signals given in the data sheet of
the encoder manufacturer.
Configuring the feedback system
Configure feedback system for motor control
Encoder settings
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