ABB ACS880 Series, Firmware Manual

Page: 97 / 764

9. Compare the estimated speed ( 1.2 ) with the measured speed ( 1.4 ). If the values
are the same, set the encoder as the feedback source ( 90.41 = Encoder 1 ).
10. Specify the action taken in case the feedback signal is lost ( 90.45 ).
Example 1: Using the same encoder for both load and motor feedback
The drive controls a motor used for lifting a load in a crane. An encoder attached
to the motor shaft is used as feedback for motor control. The same encoder is
also used for calculating the height of the load in the desired unit. A gear exists
between the motor shaft and the cable drum. The encoder is configured as Encoder
1 as shown in
Configuration of HTL encoder motor feedback above. In addition,
the following settings are made:
• 90.43 = 1
• 90.44 = 1
(No gear is needed as the encoder is mounted directly on the motor shaft.)
• 90.51 = Encoder 1
• 90.53 = 1
• 90.54 = 50
The cable drum turns one revolution per 50 revolutions of the motor shaft.
• 90.61 = 1
• 90.62 = 1
(These parameters need not be changed as position estimate is not being
used for feedback.)
• 90.63 = 7
• 90.64 = 10
The load moves 70 centimeters, ie. 7/10 of a meter, per one revolution of the
cable drum.
The load height in meters can be read from 90.7 , while 90.3 displays the rotational
speed of the cable drum.
Example 2: Using two encoders
One encoder (encoder 1) is used for motor feedback. The encoder is connected to
the motor shaft through a gear. Another encoder (encoder 2) measures the line
speed elsewhere in the machine. Each encoder is configured as shown in
Configuration of HTL encoder motor feedback above. In addition, the following
settings are made:
• 90.41 = Encoder 1
• 90.43 = 1
• 90.44 = 3
Program features 97