Velocity Feedforward Control - Siemens SINUMERIK 840D sl Function Manual

TE1: Clearance control
11.2 Clearance control
• Conversion time, channel cycle time:
ET 200 S with "2 AI U high-speed" analog electronics module produces the following
times:
-
-
• To
To is the setpoint transfer time of the drive parameterized in SIMATIC S7: HW-Config.
11.2.2

Velocity feedforward control

Eliminating the delay time
The closed-loop control gain, Kv, set for the position controller corresponds to a delay time Δt.
The display time, Δt, is the time which elapses until the actual position of the axis to be
controlled reaches the set position at a prescribed velocity of v.
and a closed-loop control gain Kv in seconds:
for an assumed closed-loop control gain Kv = 4, the corresponding delay time Δt is:
Optimizing the control response
If the control response of the axis is too rigid due to the velocity feedforward control, the
control response can be optimized with the following axis-specific NC machine data:
• MD32410 $MA_AX_JERK_TIME (time constant for the axial jerk filter).
• MD32610 $MA_VELO_FFW_WEIGHT (feedforward control factor for speed)
(840D)
The velocity filters of the SIMODRIVE 611D drive provide an additional means of damping:
• MD1502 $MD_SPEED_FILTER_1_TIME (time constant for speed setpoint filter 1)
• MD1503 $MD_SPEED_FILTER_2_TIME (time constant for speed setpoint filter 2)
460
Conversion time: 0.1 ms
Channel cycle time: 1 ms (both channels)
→ Average control deadtime of 0.5 ms
Function Manual, 09/2011, 6FC5397-2BP40-2BA0
Special Functions