Endat Encoder Interface X3A - KEB COMBIVERT F5 Operation Manual

EnDat Encoder Interface X3A

2.2.4. EnDat Encoder
Interface X3A
48
The EnDat encoder provides two differential analog channels for incremen-
tal position and one serial data channel with clock for communication with
the encoder. This serial data channel can provide the drive with the abso-
lute position of the motor as well as other operating data. The EnDat encod-
er 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.
i
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 mo-
tor 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 encod-
er 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 perma-
nent magnet motor it is necessary to synchronize the encoder position to
one of the pole pairs of the motor. See parameter LE06 for more informa-
tion and section 4.10.
During normal operation, the difference between the internal absolute posi-
tion of the encoder and the measured position value in the drive is com-
pared. 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 informa-
tion.
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.