
B–62073E–1/042. INTERFACE BETWEEN CNC AND PMC–NA OR NB
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(3) While the feed axis direction selection signal is high, rapid traverse takes place along that axis. Although
the rapid traverse override signals (ROV1, ROV2) are valid, the override is generally set to 100%.
(4) When the reference position is approached, a limit switch installed on the machine is turned on, making
the deceleration signal (*DEC1, *DEC2, *DEC3, ...) low. Consequently, the feedrate is decelerated to 0,
then the tool is fed at a constant, low speed (reference position return FL feedrate specified by parameter
setting).
(5) When the deceleration signal goes high again after the limit switch for deceleration is passed, the operation
varies depending on the method used for manual reference position return. If the grid method is used with-
out reference position proximity signals, the tool is fed with the feedrate unchanged, then the tool stops
at the first grid point (electric grid point).
Multi–axes system only.
If the method of using a magnetic switch is used, the tool is further decelerated to a constant, low speed
(reference position return FL feedrate specified by parameter setting), then the tool stops at the point when
the reference position arrival signal (ZP1, ZP2, ZP3, ...) goes high.
(6) Upon confirmation that the current position is in the effective area, the reference position return end signal
(ZP1, ZP2, ZP3, ...) goes high.
Step (2) and subsequent steps are performed independently for each axis. The standard specifications permit
simultaneous operation for up to two axes. If the simultaneous controllable axes expansion option is provided,
simultaneous movement for all controlled axes is possible.
If the feed axis direction selection signal (+J1, –J1, +J2, –J2, ...) goes low between steps (2) and (5), the tool
is stopped at once, and reference position return is assumed to be canceled. If the signal goes high again,
operation resumes from step (3) (rapid traverse).
The timing charts for the basic procedures are given below.
1) Grid method (when no reference position proximity signal is used)
J
ZRN
+J1
*
DEC1
Grid
ZP1
Feedrate