NOVA electronics Inc. MCX514 -
140
－
140
－
3.8
Acceleration / Deceleration Control in Interpolation
Interpolation is usually performed in constant speed driving; however, MCX514 can perform interpolation also in linear
acceleration / deceleration driving and S-curve acceleration / deceleration driving (linear interpolation only).
In interpolation driving, deceleration enabling (6Dh) and disabling (6Eh) commands are used to enable acceleration / deceleration
driving in continuous interpolation.
Deceleration enabling command (6Dh) is to enable the automatic and manual deceleration in interpolation driving, and
deceleration disabling command (6Eh) is to disable them. At reset, they are disabled. When the user performs single interpolation
driving at acceleration / deceleration, be sure to enable the deceleration enabling before the start of driving. If deceleration
enabling command is written during driving, it cannot be enabled.
3.8.1 Acceleration / Deceleration for Linear Interpolation
It is possible to perform trapezoidal and S-curve acceleration/deceleration driving in linear interpolation. Either automatic or
manual deceleration can be used for decelerating.
When using the manual deceleration, set the maximum absolute value among the finish points of each axis coordinates as the
manual deceleration point of the main axis. For instance, when 3-axis linear interpolation is performed with main axis: X, second
axis: Y, third axis: Z and finish point (X:-20000, Y:30000, Z:-50000), if the pulse number necessary for deceleration is 5000, the
maximum absolute value will be the finish point of Z axis, and so the user should set 50000-5000=45000 as the manual
deceleration point of the main axis: X.
For more details of examples of acceleration/deceleration driving in linear interpolation, see chapter 3.1 examples of linear
interpolation.
[Note]
•
S-curve acceleration/deceleration driving cannot be used in short axis pulse equalization mode.
3.8.2 Acceleration / Deceleration for Circular Interpolation and Bit Pattern Interpolation
In circular interpolation and bit pattern interpolation, only trapezoidal driving using manual deceleration is available, and S-curve
driving and automatic deceleration cannot be used.
The figure on the right side shows the circular interpolation of a true circle with
radius 10000 in a trapezoidal driving.
The user should calculate the manual deceleration point before driving because the
automatic deceleration cannot be used in circular interpolation.
In the figure, the circle tracks through all the 8 quadrants: 0~7. In quadrant 0, Y axis
is the short axis and it’s displace is about 10000 /
√
2=7071. The total output pulses
number of the short axis is 7071×8 = 56568.
If the initial speed is 500PPS and accelerated to 20KPPS in 0.3 SEC, the acceleration
will be (20000
−
500) /0.3 = 65000PPS/SEC. And the output pulses during
acceleration will be (500+20000)
×
0.3/2 =3075. Thus, if we set the deceleration as
same as the acceleration, the manual deceleration point will be 56568 - 3075=53493.
[Note]
•
This formula is not applied to constant vector speed mode.
WR0
←
011Fh Write
；
Select X axis
WR3
←
0001h Write
；
Deceleration start point
：
Manual
WR6
←
0003h Write
；
Set interpolation mode
：
Specify X, Y axes
WR0
←
002Ah Write
WR6
←
FDE8h Write
；
Acceleration
：
65000 PPS/SEC
WR7
←
0000h Write
WR0
←
0102h Write
