
1.AXIS CONTROL B-63323EN-1/03
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1.2.7 Follow-up
General
If the machine moves in the state in which position control on
controlled axes is disabled (during servo-off, emergency stop, or servo
alarm), feedback pulses are accumulated in the error counter. The
CNC reflects the machine movement corresponding to the error count
in the current position managed by the CNC. This operation is referred
to as follow-up. When follow-up is performed, the current position
managed by the CNC does not shift from the actual machine position.
You can select whether to perform follow-up for axes for which the
servo is turned off.
Follow-up is always performed during emergency stop or a servo
alarm.
- When follow-up is not performed for the axes for which the servo is turned off
When bit 2 (FVF) of parameter No. 1800 is set to 0, and bit 3 (FUP) of
parameter No. 1802 for the axis is set to 0,follow-up is not performed.
This means that pulses remain in the error counter as a servo error.
In this case, the machine moves to compensate for the error when the
servo off signal changes to 1.
In general, follow-up is not used if the machine is mechanically
clamped when position control is disabled for the controlled axes.
- When follow-up is performed for the axes for which the servo is turned off
When bit 2 (FVF) of parameter No. 1800 is set to 1, or bit 3 (FUP) of
parameter No. 1802 is set to 1, follow-up is performed.
This means that the issue of a command that matches the machine
movement is assumed, and the current position managed by the CNC is
moved so that the error counter becomes 0.
In this case, even when the servo off signal returns to 1, the machine
remains displaced, but the current position managed by the CNC moves
to match the machine position. So, the next absolute command causes
movement to the correct position.
In general, when the machine is moved by driving the motors with
mechanical handles, make a setting to perform follow-up.