Mitsubishi MELSEC-F Training Manual page 28

Positioning Control
Position controller
• Outputs the positioning speed
and the movement quantity in
command pulses to the servo
amplifier.
• Transfers signals between the
programmable controller.
• Controls return to the zero point.
In some types, the limit switch signal
is wired to the position controller.
Position controller
Positioning
command
Command
control
pulse
Parameter
Zero point
return
control
Operation equipment
• Give inputs for manual/automatic
mode, start/stop, zero point return
command, manual forward rotation/
reverse rotation and manual pulse
g e n e r a t o r t o t h e p o s i t i o n i n g
controller.
AC power
Near point dog signal
Main circuit
Converter
AC DC
Pulse
magnification
(Electronic gear)
Counter clear
Servo
ready
Zero point signal (PG0)
Components of Positioning Control and Their Roles 3
supply
Power board
• Improves the power factor
and cuts noise.
• Protects the power circuit.
Smoothing Regenerative
circuit brake
DC
Speed
command
Deviation
counter
Current
control
Servo amplifier
• Rectifies the AC power of the main circuit into
the DC power in the converter, and smooths it in
the smoothing circuit.
When the DC power is converted into AC power
in the inverter, the current supplied to the servo
motor is changed by the PWM (pulse width
modulation) control in the control circuit.
• The deviation counter receives and counts the
command pulses from the positioning controller,
subtracts the feedback pulses from them, then
drives the servo motor until the accumulated
pulse number becomes 0.
Servo amplifier
Inverter
DC AC
Feedback
current
PWM (pulse width
modulation) control
Feedback pulse
Dynamic
brake
R
3-2