Override Function - Mitsubishi Electric RD77MS2 User Manual

Override function

The override function changes the command speed by a designated percentage (0 to 300%) for all control to be executed.
The speed can be changed by setting the percentage (%) by which the speed is changed in "[Cd.13] Positioning operation
speed override".
Control details
The following shows that operation of the override function.
• A value changed by the override function is monitored by "[Md.22] Feedrate".
• If "[Cd.13] Positioning operation speed override" is set to 100%, the speed will not change.
• If "[Cd.13] Positioning operation speed override" is set with a value less than "100 (%)" and "[Md.22] Feedrate" is less than
"1", the warning "Less than minimum speed" (warning code: 0904H) occurs and "[Md.22] Feedrate" is set with "1" in any
speed unit.
• If "[Cd.13] Positioning operation speed override" is set to "0 (%)", the speed is set to "0" and the speed change 0 flag
([Md.31] Status: b10) is set to "1". At the time, the warning "Less than minimum speed" (warning code: 0904H) does not
occur.
• If there is not enough remaining distance to change the speed due to the "override function", when the speed is changed
during the position control of speed-position switching control or position-speed switching control, the operation will be
carried out at the speed that could be changed.
• If the speed changed by the override function is greater than the "[Pr.8] Speed limit value", the warning "Speed limit value
over" (warning code: 0991H) will occur and the speed will be controlled at the "[Pr.8] Speed limit value". The "[Md.39] In
speed limit flag" will turn ON.
[Da.8] Command speed
[Cd.13] Positioning operation
speed override
[Md.22] Feedrate
Speed change 0 flag
([Md.31] status: b10)
Precaution during control
• When changing the speed by the override function during continuous path control, the speed change will be ignored if there
is not enough distance remaining to carry out the change.
• The warning "Deceleration/stop speed change" (warning code: 0990H) occurs and the speed cannot be changed by the
override function in the following cases. (The value set in "[Cd.13] Positioning operation speed override" is validated after a
deceleration stop.)
• During deceleration by a stop command
• During automatic deceleration during positioning control
• When the speed is changed by the override function during interpolation control, the required speed is set in the reference
axis.
• When carrying out consecutive speed changes by the override function, be sure there is an interval between the speed
changes of 10 ms or more. (If the interval between speed changes is short, the Simple Motion module will not be able to
track, and it may become impossible to carry out commands correctly.)
• When a machine home position return is performed, the speed change by the override function cannot be carried out after
a deceleration start to the creep speed following the detection of near-point dog ON. When the override is enabled during
home position return and the speed is changed, the override is disabled and the speed accelerates to the creep speed after
the near point dog ON is detected.
• When deceleration is started by the override function, the deceleration start flag does not turn ON.
• The override function cannot be used during speed control mode, torque control mode or continuous operation to torque
control mode.
8 CONTROL SUB FUNCTIONS
254
8.5 Functions to Change the Control Details
50
100 0 50
50 0 25
V
150 100
75
Not affected by the override
value during deceleration.
200
50 75
Not enough remaining
distance could be secured,
so operation is carried out
at an increased speed.
t