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MELSEC-Q
3 SPECIFICATIONS AND FUNCTIONS
3.2.3 QD75 sub functions and common functions
Sub functions
The functions that assist positioning control using the QD75 are described below.
(Refer to Section 2 for details on each function.
Sub function Details
Reference
section
OPR retry function
This function retries the machine OPR with the upper/lower
limit switches during machine OPR. This allows machine OPR
to be carried out even if the axis is not returned to before the
near-point dog with JOG operation, etc.
12.2.1
Functions
characteristic
to machine
OPR
OP shift function
After returning to the machine OP, this function compensates
the position by the designated distance from the machine OP
position and sets that position as the OP address.
12.2.2
Backlash compensation
function
This function compensates the mechanical backlash. Feed
pulses equivalent to the set backlash amount are output each
time the movement direction changes.
12.3.1
Electronic gear function
By setting the movement amount per pulse, this function can
freely change the machine movement amount per commanded
pulse.
When the movement amount per pulse is set, a flexible
positioning system that matches the machine system can be
structured.
12.3.2
Functions that
compensate
control
Near pass function
1
This function suppresses the machine vibration when the
speed changes during continuous path control in the
interpolation control.
12.3.3
Speed limit function
If the command speed exceeds "
Pr.8
Speed limit value"
during control, this function limits the commanded speed to
within the "
Pr.8
Speed limit value" setting range.
12.4.1
Torque limit function 2
If the torque generated by the servomotor exceeds "
Pr.17
Torque limit setting value" during control, this function limits the
generated torque to within the "
Pr.17
Torque limit setting
value" setting range.
12.4.2
Software stroke limit
function
If a command outside of the upper/lower limit stroke limit
setting range, set in the parameters, is issued, this function will
not execute positioning for that command.
12.4.3
Functions that
limit control
Hardware stroke limit
function
This function carries out deceleration stop with the limit switch
connected to the QD75 external device connector.
12.4.4
Speed change function
This function changes the speed during positioning.
Set the new speed in the speed change buffer memory
(
Cd.14
New speed value), and change the speed with the
Speed change request (
Cd.15
).
12.5.1
Override function
This function changes the speed within a percentage of 1 to
300% during positioning. This is executed using "
Cd.13
Positioning operation speed override".
12.5.2
Acceleration/deceleration
time change function
This function changes the acceleration/deceleration time during
speed change.
12.5.3
Functions that
change control
details
Torque change function This function changes the "torque limit value" during control.
12.5.4
Absolute position restoration function 3 This function restores the absolute position of designated axis. 12.6
1: The near pass function is featured as standard and is valid only for position control. It cannot be set to be invalid with parameters.
2: Using "Torque limit function" requires a "D/A conversion module" and a "drive unit capable of torque limit command with analog voltage".
3: Using "Absolute position restoration function" requires a "16-point input module", a "16-point output module", and a "drive unit that can
construct absolute position detection system".