Siemens SINUMERIK 840D sl Programming Manual page 675

Example of adaptive control (additive)
Additive influence on the programmed feedrate
A programmed feedrate is to be controlled additive using the current of the X axis (infeed
axis):
The feedrate should only vary by +/- 100 mm/min and the current fluctuates by +/-1A around
the working point of 5A.
1. Polynomial definition
Determination of the coefficients
y = f(x) = a
a = -100mm/1 min A
1
a = -(-100)*5 =500
0
a = a
2
Upper limit = 100
Lower limit = -100
This means:
FCTDEF(1,-100,100,500,-100,0,0)
2. Activate AC control
ID=1 DO SYNFCT(1,$AC_VC,$AA_LOAD[x])
;Read the current axis load (% of the max. drive current) via $AA_LOAD[x],
calculate the path feedrate override with the polynomial defined above.
Job Planning
Programming Manual, 06/2009, 6FC5398-2BP20-0BA0
+ a x + a x + a
2
0 1 2 3
= 0 (no square and cubic component)
3
x
3
Motion synchronous actions
10.4 Actions in synchronized actions
675