Endat Encoder Interface X3A - KEB COMBIVERT F5 Reference Manual

3.3.2 EnDat Encoder
Interface X3A
i
EnDat - Encoder Connections
The EnDat encoder provides two differential analog channels for incremental
position and one serial data channel with clock for communication with the
encoder. This serial data channel can provide the drive with the absolute
position of the motor as well as other operating data. The EnDat encoder must
be version 2.1 or greater for compatibility reasons; EnDat 2.2 and only digital
EnDat 2.1 utilize the EnDat 2.2 / BiSS interface, Section 3.3.5.
The analog cosine and sine wave signals of tracks A and B have a voltage
of 1 Vpp with an Offset of 2.5 V. This analog voltage is measured and a high
resolution position value is determined as a result. This high resolution position
value is very important for good speed control of a gearless motor.
Therefore it is absolutely necessary to ensure these signals are well
shielded! Noise on the analog signals resulting from breaks in the shield
or improper shield termination will result in vibration in the motor and
poor ride quality.
The internal stored ppr value is compared to the adjusted value in LE02. If the
two are not the same the drive will trigger the 'Error Encoder Interface' fault.
Refer to parameter LE12 for more information.
During start-up and then every 30 ms a request is transmitted to the encoder
and the absolute position is read out via serial communication. This initial
readout of the absolute position provides the drive with the commutation angle
for permanent magnet motors. On the very first operation of a permanent
magnet motor it is necessary to synchronize the encoder position to one of the
pole pairs of the motor. See parameter LE06 for more information and section
5.10.
During normal operation, the difference between the internal absolute position
of the encoder and the measured position value in the drive is compared. If the
two deviate by more than 2.8 degrees, the drive will trigger the 'Error Encoder
Interface' fault. Refer to parameter LE12 for more information.
The clock signal serves as synchronization for the serial data channel.
If there is an excess length of cable (10 feet or less), it is OK to coil it into a loop
in the controller. Maintain a minimum diameter of 1 foot and keep the cable at
least 8 inches away from all high voltage power wires.
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