Moog Animatics SmartMotor™ Developer's Guide,Rev. L
Page 833 of 909
Camming - Variable Cam Example
The following code shows the use of a variable cam (versus the "fixed" cam shown in the
previous program example).
When considering use of variable cams, consider the following points:
l
Whether using variable or fixed-length segments, the base 'cam master' of the last
point is the significant part as far as executing a single cam cycle.
l
For fixed, the programmer needs to multiply the number of segments by the segment
length.
l
For variable, it is in 'absolute' terms. However, the caveat is that the programmer
should typically start with the first point as CTW(0,0) — see the following code example.
Otherwise, the difference between that and the last point must be calculated in order to
know the cam table base length.
CTE(1) ' Erase all cams in flash
CTA(8,0) ' create 8-point cam (7 segments/intervals). No segment
' length defined (variable length segments defined on a
' point-by-point basis.
CTW(0,0) ' First cam point (best practice to set to 0,0 because all cam
' base and motor position relative to this).
CTW(100,8000) ' Motor position start +100, cam base start +8000
CTW(200,10000) ' Motor position start +200 (100 greater than previous
' point), cam base start + 10000 (relative 2000 greater
' than previous point).
CTW(300,14000) ' Peak motor position of 300.
CTW(300,24000)
CTW(200,28000) ' The second parameter (cam base) is always increasing.
' The difference from the previous value must be less
' than 65535.
CTW(100,30000)
CTW(0,32000) ' Motor returns to position 0, cam base 32000.
MFSLEW(32000,1) ' Run one cycle of the cam: base 0 through 32000.
MCW(1,0) ' Select cam table 1, point 0 as the start.
G ' Start the cam relative to the present motor position.
CAUTION: When writing a cam table to EEPROM, structure the program so
that the cam table is not frequently rewritten or written from a loop. Repeated
erasing and rewriting can burn bits and corrupt data. For details and sample
code, refer to Electronic Camming Notes and Best Practices on page 159.
Camming - Variable Cam Example
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