Pressure Control Settings - Mitsubishi Electric MELSEC iQ-R16MTCPU Programming Manual

Pressure control settings

This section explains the address for feed/dwell operation, and setting method for speed/pressure.
Feed step 1
Motor speed
Load cell
pressure
Speed limit
value
Pressure
command
value
• The time constant of the switching point is set in "Feed to dwell switching speed limit value time constant" and "Feed to
dwell switching pressure command time constant". Set the switching point slightly before the position where load cell
pressure increases dramatically. When setting the mode switching point, and switching by position only, specify "0:
Address" to the feed/dwell switching mode. When also making the load cell pressure as a switching condition, specify "1:
Address & load cell pressure" to the feed/dwell switching mode, and set the switching pressure.
• For points that start deceleration at low speeds, set the point so that the motor is at a low speed until pressure increases
even slightly.
• Set pressure settings so that feed step 1 = dwell step 1. During feed, the pressure command is clamped by the speed limit
value, therefore it is not true pressure control.
• When the load cell pressure overshoots at the switching point, make the feed to dwell switching speed limit value time
constant longer.
• To make operation smooth, make the speed limit value time constant and pressure command time constant longer.
• When the motor speed at the start of operation does not reach the set speed, make the first step of pressure command
during feed larger. (Changing the value of the first step of dwell is not required.)
• When a load cell fails and becomes a high pressure, the motor continues reversing in order to lower pressure and may
collide with machinery. Set a stroke limit to prevent a collision.
• The servo parameter "Pressure control F/B input offset (PT21)" is normally set to "0". When adjusting offset with the user
program, change the servo parameter with the servo parameter read/change function. Refer to the following for details on
the servo parameter read/change function.
MELSEC iQ-R Motion Controller Programming Manual (Common)
7 AUXILIARY AND APPLIED FUNCTIONS
460
7.7 Pressure Control
Feed Dwell
step 2 step 1
Feed
Switching point
*: is change by the time constant setting.
Dwell step 2
Dwell