NOVA electronics Inc. MCX514 -
129
－
129
－
3.5
Constant Vector Speed
Vector speed is the driving speed of the tip of a locus performing interpolation driving, and it is also called Head speed. In
operations such as machining or coating workpieces during interpolation driving, it is important to keep this vector speed constant.
MCX514 provides 2-axis simple constant vector speed mode and 2-axis high accuracy constant vector speed mode for 2-axis
interpolation. In addition, it provides 3-axis simple constant vector speed mode for 3-axis interpolation.
Fig. 3.5-1 shows the locus of 2 axes interpolation in the
orthogonal XY plane. Each axis outputs drive pulses according to
the basic pulse of the main axis. And as shown in the figure, when
both axes output drive pulses, it moves 1.414 times longer
distance than that of 1-axis output.
If not using constant vector speed mode when both axes outputs
drive pulses, the speed will be 1.414 times faster even though the
driving distance is 1.414 times longer.
Fig. 3.5-1 Example of 2-axis Interpolation
Fig. 3.5-2 shows the speed deviation of vector speed within the range from 0 to 90 degrees of the angle between X axis and the
line to be interpolated when linear interpolation is performed in the orthogonal XY plane. Although the figure shows the range 0
－
90 degrees, the range 90
－
180, 180
－
270, 270
－
360 are the same.
a. Constant vector speed: disabled
b. 2-axis simple constant vector speed
c. 2-axis high accuracy constant vector speed
Fig. 3.5-2 Speed Deviation of Vector Speed with respect to Setting Speed in Linear Interpolation Driving
Fig. 3.5-2 a. is the speed deviation of vector speed with respect to the setting drive speed when constant vector speed mode is
disabled. When the angle from X axis is 45 degrees, the speed deviation will be maximum and the speed will increase by
approxi41%.
Fig. 3.5-2 b. is the speed deviation in 2-axis simple constant vector speed mode, where the speed deviation is improved by setting
1/1.414 times pulse cycle for both axes pulse output.
Fig. 3.5-2 c. is the speed deviation in 2-axis high accuracy constant vector speed mode, where the speed deviation can be kept
±0.2%
*1
or less in the range of all angles.
*1
：
Short axis pulse equalization mode must be enabled.
3-axis simple constant vector speed mode is available for 3-axis linear interpolation, where the speed deviation is improved by
setting 1/1.414 times pulse cycle when pulses of any 2 axes among 3 axes are output, and improved by setting 1/1.732 times pulse
cycle when pulses of all 3 axes are output.
Ｙ
Ｘ
Speed becomes
1.414 times faster.
0
45
90
+10
+20
+30
+40
Speed Deviation
(%)
0
-10
-10
the maximum
＋
41
％
the maximum
－
7.6
％
0
45
90
0
45
90
the maximum ±0.2
％
+10
-10
Angle(°)
+10
Speed Deviation
(%)
Speed Deviation
(%)
Angle
(°)
Angle
(°)
0
0
Ｙ
Ｘ
θ
Angle(°)
Deviation of resultant speed
Enable short axis pulse equalization mode
