PPRO defines the ratio for a proportional axes to a given X and/or Y axis. This proportional axes move in proportion to the X-Y path motion. Since the scaling is a bit confusing, the examples below should explain it.
Note that DRES and ERES do not effect distance.
1) No scaling.
SCALE0
DEL PATH
DEF PATH
PAXES1,2,3,4
PPRO2
PLIN1000,500
END
PCOMP PATH
PRUN PATH
At the end of the move the commanded position is "*TPC+1000,+500,+0,+2236."
Since the proportional axis is based off of the path distance, which is the vector equivalent of the X and Y distance, we must calculate the vector distance.
Vector Distance = SQRT(1000^2 + 500^2) = 1118 counts
The proportional axis should be the Vector Distance times the PPRO value.
Proportional distance = PPRO * Vector Distance = 2 * 1118 = 2236.
2) Scaling different on X-Y axis vs Proportional Axis
SCALE1
SCLD4000,4000,25000,25000
SCLV4000,4000,25000,25000
SCLA4000,4000,25000,25000
DEL PATH
DEF PATH
PAXES1,2,3,4
PPRO2
PLIN2,1
END
PCOMP PATH
PRUN PATH
At the end of the move the commanded position is "*TPC+2.000,+1.000,+0.0000,+0.7155"
Vector Distance = SQRT((2*4000)^2 + (1*4000)^2)) = 8944 counts
Proportional Distance = 2 * 8944 = 17888 counts
Scaled Proportional Distance = 17888 / 25000 = 0.7155 units
3) Scaling Different on all axis.
SCALE1
SCLD4000,8000,25000,25000
SCLV4000,8000,25000,25000
SCLA4000,8000,25000,25000
DEL PATH
DEF PATH
PAXES1,2,3,4
PPRO2
PLIN2,1
END
PCOMP PATH
PRUN PATH
At the end of the move the commanded position "*TPC+2.000,+1.000,+0.0000,+1.4310"
This is the wierd one. The Proportional axis is always calculated based on the larger of the two X and Y scaling factors. In this case the larger of the two is 8000 so the vector distance is calculated based on a scaling factor of 8000.
Vector Distance = SQRT((2*8000)^2 + (1*8000)^2)) = 17888 counts
Proportional Distance = 2 * 17888 = 35777 counts
Scaled Proportional Distance = 35777 / 25000 = 1.4310 unitsNote that the actual distance the X axis moves is proportional to it's own scaling factor, only the proportional axis uses the higher scaling factor.