M
OTION
C
ONTROL
Networked Indexer/Driver User Manual
ADVANCED MICRO CONTROLS INC.
38
Electronic Gearing
The final form of motion control available with a Networked Driver is Electronic Gearing. A quadrature
encoder is required but it is not mounted on the motor controlled by the Networked Driver. The encoder is
typically mounted on a second motor, but it can be mounted anywhere, including on something as simple as a
hand crank.
This mode is sometimes referred to as
encoder following
, because the motor will change position in response
to a change in position of the encoder. AMCI refers to it as Electronic Gearing because the Networked Driver
has three parameters that allow you to set any turns ratio you want between the encoder and the motor.
Motor_Resolution
This is the same parameter explained at the beginning of this chapter. In Electronic Gearing mode, this
parameter sets the number of encoder counts required to complete one rotation of the shaft of the motor
driven by the Networked Driver. It has a range of 200 to 32,767. If you set the Motor_Resolution parameter to
four times the number of lines of your encoder, then by default your motor will complete one rotation for
every rotation of the encoder.
ELGearing Multiplier and Divisor
The ratio of these two parameters sets the number of motor rotations per encoder rotation. Each parameter has
a range of 1 to 255.
How It Works
The Networked Driver always uses 4X decoding when counting pulses from the encoder. If you set the
Motor_Resolution parameter to four times the number of encoder lines, and set both of the ELGearing Multi-
plier and Divisor parameters to 1, then the motor will complete one rotation for every rotation of the
encoder’s shaft.
Once placed in Electronic Gearing mode, the Networked Driver monitors the Jog Move command bits in the
Network Output Registers. When either of these bits are set, the encoder inputs are monitored for a change in
position. When a change is sensed, the Networked Driver will begin to turn the motor within 50 microsec-
onds. An increase in encoder counts will result in clockwise rotation. A decrease in encoder counts will result
in counter-clockwise rotation.
The values of the ELGearing Multiplier and Divisor can be changed while electronic gearing motion is occur-
ring. The Networked Driver will accelerate or decelerate the motor to match the new ratio.
Encoder position data can be captured and reported to the host controller while in Electronic Gearing mode
by configuring Input 3 as a Capture Encoder Position input.
You must set the Acceleration and Deceleration parameters before you can put the Networked
Driver in Electronic Gearing mode.
You cannot use Stall Detection when using Electronic Gearing. Stall detection requires that the
encoder be mounted to the motor you are controlling. Electronic Gearing requires that the
encoder not be mounted on the motor you are controlling.
