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
The encoder turns three revolutions per one revolution of the motor shaft.
•
90.51 = Encoder 2
Program features 59
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