Mitsubishi Electric MELSEC iQ-R16MTCPU Programming Manual page 227

High-accuracy control operation when combined with each function
The high-accuracy control operation for each function is shown below.
Function
Normal line control
Polar coordinate interpolation
*1 Any of the following cases
• When the rotating angle of the block joint is less than or equal to the G-code control system parameter "minimum rotating angle".
• When the block afterwards is linear interpolation and the movement amount is less than the G-code control system parameter
"minimum rotating movement amount".
• When the block afterwards is circular interpolation and the diameter value is less than the G-code control system parameter "minimum
rotating movement amount".
Operation
• When normal line control and high-accuracy control mode are used together, set the parameters so that tolerable
acceleration control for each axis is enabled. When tolerable acceleration control for each axis is disabled, and a
G61.1 command is made during normal line control, a minor error (error code: 1FC3H (details code: 0304H))
occurs. Also, when normal line control is started by a G41.1 of G42.1 command, a minor error (error code: 1FC3H
(details code: 0304H)) occurs.
• During normal line control, the independent operation of a rotating axis uses acceleration/deceleration after
interpolation. When the rotating axis operates at the joints in between blocks, it switches between acceleration/
deceleration before interpolation and acceleration/deceleration after interpolation therefore a deceleration check is
performed.
• When the rotating axis operation between blocks does not do an independent operation
synchronized with the circular interpolation operation. Therefore calculate the optimum deceleration speed so that
the acceleration speed at block joints is equal to or lower than the tolerable acceleration for the rotating axis, and
decelerate to that speed in advance. After switching blocks, accelerate to the command speed once again.
[Operation example]
<Program>
(G61.1)
:
N1 G41.1 G90 G01 X10. F3000
N2 G02 X20. Y-10. I0. J-10.
<Speed pattern>
Composite speed
Speed command (F)
Deceleration speed (Fc)
calculated from normal
line control axis
deceleration speed (fc)
Normal line control axis speed
Rotating speed of normal
line control axis (f)
Deceleration speed (fc)
calculated from tolerable
acceleration speed
■Caution
Because the speed is not clamped by the tolerable acceleration speed of the rotating axis at circular interpolation
during normal line control, if the radius of the arc is small, the acceleration of the rotating axis may become larger than
the tolerable acceleration of the rotating axis. When the radius of the arc is small, make the settings so that the
tolerable acceleration for all axes is a smaller value compared to the tolerable acceleration of the rotating axis.
When polar coordinate interpolation mode and high-accuracy control mode are used together, set the parameters so
that tolerable acceleration control for each axis is enabled. When tolerable acceleration control for each axis is
disabled, and a high-accuracy control mode command (G61.1) is made during polar coordinate control, a minor error
(error code: 1FC3H (details code: 0322H)) occurs. Also, when polar coordinate mode start command (G12.1) is
commanded during high-accuracy control mode, a minor error (error code: 1FC3H (details code: 0324H)) occurs.
<Operation>
N1
N2
N1 N2
N1 N2
Control so that acceleration of the
normal line control axis is equal to or
less than the tolerable acceleration of
the normal line control axis
6 AUXILIARY AND APPLIED FUNCTIONS
*1
, the rotating axis is
Time
Time
6.7 High-Accuracy Control
6
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