Siemens SINUMERIK 840D sl Function Manual page 404

Compensations (K3)
Dynamic feedforward control (following error compensation)
Commissioning
The following procedure should be followed to activate the feedforward control:
1. Check the stoppage velocity in MD36060.
2. Check the existing following error of the axis in stoppage condition.
3. Set and activate the changeover condition via machine data:
4. Traverse axis in the part program via POSA instruction.
5. Execute FFWON during the axis motion.
6. The Kv and following error displayed in the "Axis service image" should not be exceeded.
7. A higher Kv and a smaller following error are adjusted only during a stoppage of the next
The shutoff operation is similar to the activation of the feedforward control:
1. Traverse axis in the part program via POSA instruction.
2. Execute FFWOFF during the axis motion.
3. The Kv and following error displayed in the "Axis service image" should not be exceeded.
4. A lower Kv and a bigger following error are adjusted only during a stoppage of the next
Sample programming
In the following example, Axis A is traversed asynchronously to the path. An attempt is made
to activate the feedforward control in the channel during the traverse. Unlike in case of the
geometry axes X, Y and Z, the feedforward control is not immediately effective for Axis A.
Here one waits for the stoppage after N60. Axis A then traverses with the feedforward
control in N70.
Programming
N10 FFWOF
N20 POSA[A]=1000 FA[A]=10000
N30 G4 F1
N40 FFWON
N50 G0 X10 Y10 Z10
N60 WAITP(A)
N70 POSA[A]=1500 FA[A]=10000
N80 WAITP(A)
M30
404
MD32630 $MA_FFW_ACTIVATION_MODE = 2.
traverse movement. However, the feedforward control is active only from the stoppage
condition.
traverse movement. However, the feedforward control is inactive only from the stoppage
condition.
Function Manual, 03/2009, 6FC5397-1BP10-4BA0
Extended Functions