
4. REFERENCE POSITION ESTABLISHMENT
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By reversing the formula above, the following formula gives the feedrate
F needed to obtain a servo position error of 128, when the servo loop gain
G is 30 s
–1
and the detection unit U is 1 mm:
F=
128 60
1000
30
= 230 [mm/min]
Therefore, when the servo loop gain is 30 s
–1
, the detection unit is 1 mm,
and parameter No. 1836 is set to 128, the tool must be fed in the reference
position return direction at a speed of at least 230 mm/min before
completing manual reference position return.
The electronic grid can be shifted by the distance set in parameter 1850,
thus shifting the reference position. The grid shift to be set in the
parameter must not exceed the reference counter capacity (parameter No.
1821) (grid interval).
[Classification] Input signal
[Function] This signal selects manual reference position return. Manual reference
position return is a kind of jog feed. Therefor, to select manual reference
position return, it is required that the jog mode be selected and that the
manual reference position return selection signal be set to “1”.
[Operation] When the manual reference position return selection signal is set to “1”,
the control unit performs as described below.
D If jog feed mode is not selected, the control unit ignores the manual
reference position return selection signal.
D If jog mode is selected, manual reference position return is enabled.
In this case, the manual reference position return selection check
signal MREF turns to “1”.
NOTE
If the ZRN status changes state during jog feed, the
feedrate is decelerated to 0. Then, to restart reference
position return or jog feed, turn feed axis and direction
selection signal to “0” then set it to “1”.
Grid shift
Signal
Manual reference
position return selection
signal ZRN <G043#7>