Yaskawa YASNAC PC NC Programming Manual - Manual (Page 45)

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YASNAC PCNC Programming Manual Chapter 2: Commands Calling Axis Movements
(4) Supplements to the Automatic Reference Point Return Commands
• It is possible to select valid/invalid of reference point return for each axis. If the axis
for which “reference point return invalid” has been set is specified in the G28 block,
alarm “0241” occurs. Refer to parameter pm4002 D0 to D4.
• It is possible to display alarm “0411” (X-axis) to “0415” (5th-axis) if the cycle start
switch is pressed without carrying out reference point return for all axes after turning
ON the power. Whether or not such alarm display should be given is determined by
the setting for parameter pm4001 D6. For the axes for which the setting is “D6 = 1 (to
generate alarm)”, setting is possible whether or not the reference point return is neces-
sary for a parameter. Refer to parameter pm4018 D0 to D4 (X-axis to 5th-axis).
• “It is possible to display alarm “0411” (X-axis) to “0415” (5th-axis) when an axis
move command other than G28 is executed without completing reference point return
after turning ON the power. Whether or not such alarm display should be given is
determined by the setting for a parameter. Refer to parameter pm4004 D0 to D4 (X-
axis to 5th-axis).
• “The absolute coordinate values of the axes specified in the G28 block are saved to
memory as the intermediate positioning point. For the axes not specified in the G28
block, the intermediate positioning point saved in the previous reference point return
operation remains valid.
• If M, S, T, and/or B command is specified with G28 in the same block, the axes con-
tinue moving to the reference point disregarding whether or not the FIN processing is
completed before the positioning of an axis at the intermediate positioning point.
Therefore, DEN is output at the reference point.
• The deceleration limit switch position must be carefully attended to when executing
the reference point return for the first time after turning ON the power. For details,
refer to 2.4.2, “Manual Reference Point Return” of the Operating Manual.
2.2.2 Reference Point Return Check (G27)
This function checks whether the axes are correctly returned to the reference point at the comple-
tion of the part program which is created so that the program starts and ends at the reference point
in the machine by specifying the commands of “G27 X • • • Y • • • Z • • • (*a • • • b • • •);”.
In the G27 mode, the function checks whether or not the axes positioned by the execution of these
commands in the simultaneous 3-axis (* 5-axis) control mode are located at the reference point.
For the axes not specified in this block, and not moved although the axis command specified,
positioning and check are not executed.
(1) Operation after the Check
When the position reached after the execution of the commands in the G27 block agrees with
the reference point, the reference point return complete lamp lights. The automatic operation
is continuously executed when all of the specified axes are positioned at the reference point.
If there is an axis that has not been returned to the reference point, reference point return
check error (alarm “0421” (X-axis) to “0425” (5th-axis)) occurs and the automatic operation