YASKAWA SERVOPACK Sigma 7 Series, Product Manual, Page: 55 / 342

3.3 Operation Patterns for Pressure Feedback Control
3-5
3
Pr
essur
e Feedback Contr
ol
3.3 Operation Patterns for Pressure Feedback Control
An example of pressure feedback control is provided below. In this example, the control
method is changed from torque control to pressure feedback control.
•
Pressure feedback control will be performed if the TRQCTRL (Torque Control) command (3Dh)
is executed while pressure feedback control is enabled (Pn440 = n.

1) and the pressure
feedback detection value exceeds the pressure feedback enable level.
•
To suppress shock when changing the control method, change the control method under the
following conditions.
Changing from Torque Control or Pressure Feedback Control to Position Control or Speed
Control:
Stop the motor before changing the control mode.
Changing from Position Control or Speed Control to Torque Control:
Set a speed limit (Pn407) for torque control or a speed limit (Pn480) for force control and keep
the speed constant.
•
If the torque limit is released when operating with the pressure feedback detection value at or
below the pressure feedback reference value due to the torque limit, excess torque may be
applied to the Servomotor. This creates a risk of workpiece and machine damage.
Set appropriate values for the pressure feedback loop deviation overflow level (Pn447), torque
limit (Pn402 or Pn403), external torque limit (Pn404 or Pn405), and torque limit and force limit
(Pn483 or Pn484) set with MECHATROLINK-III commands.
Important
Height from
pre
ss ing
po s ition
Time
Time
Pre ss ure
Approach height
S earch po s ition
(detection po s ition for the
pre ss ure feedback enable level)
Pre ss ure feedback control
s tarting pre ss ure
(Pre ss ure Feedback
Enable Level)
Pre ss ing pre ss ure
Po s ition control
Po s itioning command
(PO S ING: 3 5h)
or other po s ition
control command
Po s itioning command
(PO S ING: 3 5h)
or other po s ition
control command
Torque control
Pre ss ure feedback control Po s ition control
S peed
limit
0
Pre ss ing po s ition
Pre ss ing
direction
Control mode
Torque control command
(TRQCTRL:
3 Dh)