LASTLOOP=ANGLE - (LOOPCNT*32000)
ANGLE=32000
#MOVE
CNT=0
#LOOP
VMXY
CR RADIUS,0,ANGLE
VE
BGS
AMS
CNT=CNT+1
JP#LOOP,CNT<LOOPCNT
ANGLE=LASTLOOP
JP#LOOP,(CNT<(LOOPCNT+1)) & (LASTLOOP > 0)
EN
In the above example, a circle is created using the X and Y axes of the controller. The Z
axis is geared to the coordinated motion of the X and Y axes to create the helix. The
gear RATIO is determined by the PITCH of the helix and the circumference of the
circle.
One unavoidable limitation of the circle (CR) command is that the maximum swept
ANGLE of a circle must be less than 32,000 degrees. As a result, the program executes
multiple passes of #LOOP for any calculated angle greater than 32,000 degrees.
Method to Increase Accuracy of Helical Motion
For the highest possible accuracy, it is recommended that the gear ratio be calculated
using the formula ratio=pitch/(2*pi*radius) on a standard calculator. The resolution of
the controller is limited to approximately four decimal places so the ratio you enter
should be the gear ratio you calculate truncated to four decimal places. You will now
need to calculate the amount of error you accumulate during the helical motion due to
rounding so that the #CORRECT routine can compensate for it. For more information
about Gearing Resolution, See Application Note 3010.
First, you need to determine the value of the gear ratio as internally represented by the
controller. The controller stores decimal values as fractions with a resolution of
1/65,536. To determine the internal value of the gear ratio, multiply the entered gear
ratio by 65,536, truncate any fractional part of the result, and divide by 65,536. You can
also determine this directly by typing in a gear ratio (ex. GR ,,.0114) and then
multiplying the _GRn operand by 10,000 and displaying the result (ex. MG
_GRZ*10000). This result divided by 10,000 should give you the same result as the
calculation method.
Next, determine the amount of error that results from the rounding of the gear ratio. To
do this, you must calculate the distance which the geared axis will travel and compare it
to the distance you specified using DIST. The actual distance traveled is equal to the
