Mitsubishi Electric MELSEC-L LD75P User Manual page 406

(4) 3-axis helical interpolation control with sub point designation (ABS helical
sub)
(a) Operation chart
In this control, positioning is carried out from the current stop position (X0, Y0, Z0) to the circular end address
(X1, Y1) and linear axis end address (Z1) set in "[Da.6] Positioning address/movement amount". Circular
interpolation where the arc path passes through the address of the sub point (sub point address) set in "[Da.7]
Arc address" is carried out. Simultaneously, linear interpolation is carried out with the other linear axis. The
control path is helically rotated for the number of pitch set in "[Da.10] M code" of the linear axis to complete the
positioning to the specified position.
The resulting control path is an arc having its center as the intersection point of perpendicular bisectors of a
straight line between the start point address (current stop position) and sub point address (arc address), and a
straight line between the sub point address (arc address) and end point address (positioning address).
Operation chart
Linear movement
amount
Z axis
Y axis
X axis
Arc sub point
(b) Restrictions
3-axis helical interpolation control cannot be set in the following cases.
• When "degree" is set in "[Pr.1] Unit setting" for the reference axis and circular interpolation axis
• When the units set in "[Pr.1] Unit setting" are different between the reference axis and circular interpolation
axis. ("mm" and "inch" combinations are possible.)
• When a method other than "composite speed" is set in "[Pr.20] Interpolation speed designation method" or
"[Da.29] Interpolation speed designation method"
An error will occur and the positioning will not start in the following cases. The machine will immediately stop if
the error is detected during positioning control.
When the radius exceeds "536870912 (= 2
which circular interpolation control is possible is "536870912 (= 2
Center point address is outside the range of 2147483648 (2
31
 1).
2147483647 (2
Start point address = End point address
Start point address = Sub point address
End point address = Sub point address
When the start point address, end point address, and sub point address are in
a straight line
404
Circular interpolation control
end point (X1, Y1)
Linear control end point (Z1)
Number of pitch
Circular interpolation control
start point (X0, Y0)
Linear control start point (Z0)
Error cause
29
)". (The maximum radius for
29
31
) to
Arc sub
point
An error "Outside radius range" (error code: 544) will occur at positioning start.
)".)
An error "Sub point setting error" (error code: 525) will occur at positioning
start.
Error "End point setting error" (error code: 526)
Error "Sub point setting error" (error code: 525)
Error "Sub point setting error" (error code: 525)
Error "Sub point setting error" (error code: 525)
Circular interpolation plane
Circular interpolation
control end point (X1, Y1)
Center point
Circular interpolation
control start point (X0, Y0)
Error code