Yaskawa MP2000 Series: User's Manual for Motion Programming - Manual (Page 140)

8.1 Axis Setting Commands
8-33
8
Command Reference
(c) Motor Speed Specifications
In addition to the VEL command reference range, the motor rated speed and max. speed must be taken into
consideration to decide the set value for the VEL command. To avoid causing an overspeed, check the speed
specifications of your motor before setting a value for the VEL command.
For rotational motors, the speed specifications are expressed in unit of rotations per specified time of period.
The rated speed when the speed unit is 10
n reference units/min is calculated according to the motion fixed parameter set-
tings.
• Parameter Setting Example: When Electronic Gear is Enabled
Note: When motion fixed parameter 4 (Reference unit selection) is set to a unit other than pulse, the elec-
tronic gear is valid.
When the electronic gear is enabled, n of the speed unit 10 n reference units/min is the number of digits below the decimal
point. Therefore, the speed unit is:
10 n reference units/min = 10 3
• 0.001mm/min = [mm/min]
The machine shaft rotation speed when the motor rotates at the rated speed:
Rated speed [rotations/min] × Gear ratio
= 3000 × (2/3) = 2000 [rotations/min]
To convert the number of rotations of the machine shaft into a reference unit (0.001 mm),
Travel distance per machine rotation [0.001 mm/rotation] × 2000 [rotation/min]
= 10000 × 2000 = 20000000 [0.001mm/min]
Because the speed unit is [mm/min],
20000000[0.001mm/min] = 20000[mm/min]
- Continues to the next page -
Motion fixed parameters
• No. 4: Reference unit selection = mm
• No. 5: Number of digits below decimal point = 3
• No. 6: Travel distance per machine rotation = 10000 reference units
• No. 8: Servo motor gear ratio: 3
• No. 9: Machine gear ratio = 2
• No. 34: Rated motor speed = 3000 rotations/min
INFO
Ball screw
Workpiece
Motor The machine shaft rotates two times when
the motor is rotated three times (gear ratio)
The table moves 10 mm for each rotation of the
machine shaft
(Travel amount per one machine rotation)