Backlash Compensation; Feedback Pulse Multiplication - Fuji Electric micrex-sx SPH User Manual

7-3-22 Backlash compensation

• This module (NP1F-MP1/MP2) compensates for backlash.

7-3-23 Feedback pulse multiplication

• When feedback pulse is enabled, this function is used for the weighting of the command pulse and feedback pulse.
The figure below shows the relationship between the pulse multiplication function on the module side (NP1F-MP1/
MP2) and that on the servo amplifier side.
This module
Pulse
generator
Command pulse
multiplication
Position
monitor
• On the servo amplifier side, command pulse multiplication (x1, x2, x4) is set.
According to the set multiplication, the number of revolutions of the motor per single command pulse changes.
• On the module side, because feedback pulses are counted after being multiplied by 4, command pulse
multiplication becomes as follows:
x1: For one feedback pulse (multiplied by 4)
x2: For 2 feedback pulses
x4: For 4 feedback pulses
• On the module side (NP1F-MP1/MP2), the displacement of work is monitored by the difference between the
command pulse count and feedback pulse count, but it is necessary to set the command pulse multiplication so as
to match the multiplication set for the servo amplifier. This multiplication is set in the feedback pulse multiplication
register.
Example:
· Maximum speed: 3000r/min
Encoder pulse count: 2000 pulses/revolution (when multiplied by 1)
For this combination of servo amplifier and motor, when multiplied by 4, the feedback pulse at the maximum
speed becomes 400kHz.
In this case, it is necessary to set the command pulse frequency to 400kHz.
• With this module (NP1F-MP1/MP2), feedback pulse is multiplied by 4 when the phase differential is 90 degrees.
When feedback pulse multiplication is set, because the processing of multiplication is actually made on the
command pulses, current command position data is also multiplied.
7-3 Functions of Pulse Generation Mode
Servo amplifier
Command
pulse
Command pulse
multiplication
Feedback
pulse
(multiplied by 2)
(multiplied by 1)
7-29
Deviation
Motor
counter
PG