Specifications

A - 52
POSITIONING PARAMETERS
This is basic data for carrying out positioning
control. Types of data include the system
settings set to match the servomotor and servo
amplifier being used, the control unit,
movement amount per pulse, speed limit
value, upper and lower stroke limit values, and
acceleration/deceleration time, etc.
POSITION LOOP GAIN
This is an item in the positioning data's servo
parameters, and indicates the speed of the
control response during positioning control.
The No. of droop pulses in the deviation
counter is specified during operation, and if the
setting value is high, the droop pulses
decrease allowing the settling time when
stopping to be shortened. However, if too high,
undershooting may occur during stopping, or
there may be vibration when stopping. If the
setting value is small, the droop pulses will
increase, thereby causing the settling time
when stopping to increase. This may allow
smooth stopping, but will increase the stopping
error.
Command pulse frequency
Position
loop gain
=
Droop pulses
(sec
-1
)
POSITION LOOP MODE
This is one servo control mode used in
positioning. It is a mode for carrying out
position control. The other servo control modes
are the speed loop mode for carrying out
speed control, and the torque loop mode for
carrying out torque control (current control).
M
PLG
Servo amplifier
Servomotor
Pulse train
Droop pulses
Posi-
tion
control
Speed
control
Cur-
rent
control
Inverter
Current feedback
Speed feedback
Position feedback
Interface
PTP Control (Point To Point Control)
This is a type of positioning control. With this
control method, the points to be passed are
designated at random locations on the path.
Movement only to a given target positioning is
requested. Path control is not required during
movement from a given point to the next value.
PULSE
Refers to the current (voltage) turning ON and
OFF within a short time. Similar to the human's
pulse. A pulse train is a sequence of pulses.
The MELSEC AD71 is a unit that generates
pulses.
AD61 is a unit that receives and counts the
pulses.
PULSE COMMAND
Command that turns ON only one cycle (1
scan) of the program when the condition is
ON. With the MELSEC-A, one scan time is the
rising edge of when the signal turns ON.
Commands include the PLS command that
turns ON, and the PLF command that turns
one scan time ON at the falling edge of the
OFF command.
PULSE GENERATOR
This is a device that generates pulses.
Examples include devices installed on the
motor shaft that create pulses when the shaft
rotates, and digital devices.
1-phase types output one pulse train. 2-phase
types output two pulse trains with a phase
difference. From 600 to 1,000,000 pulses can
be output per shaft rotation. Generators with a
ZERO POINT signal function to output 1 or 2
pulses per shaft rotation. Abbreviated as PLG.
Refer to the term "ENCODER".