Mitsubishi Electric MELSEC-L LD75D, User Manual

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APPENDICES
A
Appendix
8
ME
LSE
C
E
xplanat
ion
of
Pos
itioning T
e
rm
s
TRAPEZOIDAL
ACCELERATION/DECELERATION
An operation in which a graph of the time and speed takes a trapezoidal shape.
STEP OUT
Stepping motors rotate in proportion to the No. of pulses (frequency), but the motor's rotation will deviate if the
load is too large for the motor. This is called step out. If step out occurs, the motor must be replaced by one with
a larger torque. Step out causes the positioning error to increase.
UNIT SETTING
This is the setting of the unit for the actual address to which positioning is required, or for the movement amount.
The following units can be set: mm, inch, degree and pulse.
The initial value in the parameters is a pulse unit.
LINEAR INTERPOLATION
This automatic operation simultaneously operates two motors for the latitudinal (X) feed and longitudinal (Y) feed
to move a target in a diagonal line for positioning. Three or four motors can also be operated simultaneously.
The LD75 combines the operation of axis 1 through 4 for the linear interpolation. The same positioning data No.
must be used for the setting. Refer to the term "INTERPOLATION OPERATION".
LOW-INERTIA MOTOR
This is a motor used when frequent acceleration/deceleration is repeated.
Low-inertia motors are longitudinally longer, to decrease the rotor diameter and cover the torque. This enables
their inertia moment to be reduced up to 1/3 that of standard motors.
The ideal load inertia ratio is 1 or less.
FIXED-FEED
This is the feeding of a set dimension for cutting sheet and bar workpieces into the designated dimensions.
Incremental system positioning is often used. The current value is not incremented, even when the feed
operation is repeated.
MULTIPLYING RATE SETTING
The P rate.
Refer to the term "P RATE".
ELECTRONIC GEAR
This function electrically increases/decreases the command pulses from the pulse command module by 1/50 to
50-fold. Thus, the positioning speed and movement amount can be controlled by the electronic gear ratio
magnification.
ELECTROMAGNETIC BRAKE
This function is supplied on motors with electromagnetic brakes. Electromagnetic brakes are used to prevent
slipping during power failures and faults when driving a vertical axis, or as a protective function when the
machine is stopped.
These brakes are activated when not excited.
CURRENT LOOP MODE
One of the servo control modes in positioning. Mode which uses current for torque control. Also called the torque
loop mode.
Refer to the term "POSITION LOOP MODE".
INPUT TERMINAL
This is a pin connector wired by the user for inputting data to the LD75 from an external source.
It is connected to the motor drive unit or machine side. This terminal is used to output the following.
• DRIVE UNIT READY signal
• START signal
• STOP signal
, etc.
The input No. Xn is not directly related to the program, so it is not used.
Term Description
Acceleration
Speed
Time
Deceleration
Motor
Motor
torque
Load
No.9
No.8
No.1
2
3
4
5
6
7
Longitudinal
feed
Latitudinal feed