ABB ACS880 Firmware Manual page 50

50 Program features
Encoder echo and emulation
Both encoder echo and emulation are supported by the above-mentioned FEN-xx
interfaces.
Encoder echo is available with TTL, TTL+ and HTL encoders. The signal received
from the encoder is relayed to the TTL output unchanged. This enables the
connection of one encoder to several drives.
Encoder emulation also relays the encoder signal to the output, but the signal is
either scaled, or position data converted to pulses. Emulation can be used when
absolute encoder or resolver position needs to be converted to TTL pulses, or when
the signal must be converted to a different pulse number than the original.
Load and motor feedback
Three different sources can be used as speed and position feedback: encoder 1,
encoder 2, or motor position estimate. Any of these can be used for load position
calculation or motor control. The load position calculation makes it possible, for
example, to determine the position of a conveyor belt or the height of the load on a
crane. The feedback sources are selected by parameters
selection and 90.51 Load feedback
For detailed parameter connections of the motor and load feedback functions, see
the block diagrams on pages
calculation, see section
Any mechanical gear ratios between the components (motor, motor encoder, load,
load encoder) are specified using the gear parameters shown in the diagram below.
Load encoder to load
scaling
90.53
e X
Y
Load encoder
90.54
Any gear ratio between the load encoder and the load is defined by
numerator and 90.54 Load gear
motor encoder and the motor is defined by
90.44 Motor gear denominator. In case the internal estimated position is chosen as
load feedback, the gear ratio between the motor and load can be defined by
90.61 Gear numerator
mentioned above are 1:1. The ratios can only be changed with the drive stopped;
new settings require validation by
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selection.
577 and 578. For more information on load position
Position counter (page 51).
1
X
Load
Y
denominator. Similarly, any gear ratio between the
and 90.62 Gear denominator. By default, all of the ratios
91.10 Encoder parameter
90.41 Motor feedback
Motor to load Motor encoder to motor
scaling
90.61 90.43
X
M
Y
90.62 90.44
90.43 Motor gear numerator
refresh.
scaling
X
X
e
Y
Y
Motor
encoder
90.53 Load gear
and