
B. PARAMETERS
B--65245EN/02
APPENDIXES
200
CAUTION
On an axis where the absolute --position detector is used,
the reference position is stored using the coordinates of the
absolute -- position detector. On a rotation axis, to preserve
the positional rela tionship between the coordinates of the
absolute--position detector and the reference position, the
coordinates of the absolute -- position detector that
correspond to the reference position must b e shifted each
time movement is performed by the amount of movement
per rotation axis revolution specified for position parameter
No. 141. (See the figure below.)
Because the reference position is stored u sing the
coordinates of the absolute-- position detector, the reference
position is shifted in the absolute-- position detector pulse
units corresponding to one revolution.
The formula for converting the amount of movement per
rotation axis revolution into the movement amount of the
absolute--position detector (Lp) is as follows:
Lp = Amount of movement per rotation axis revolution
(parameter No. 141)×K
×Denominator for the number of pulses per motor
revolution (parameter No. 106)×2
16
÷Numerator for the number of pulses per motor
revolution (parameter No. 105)
Currently, if either of the following two conditions is satisfied
during the above conversion, Lp contains a fractional part.
Because the servo amplifier unit rounds off Lp to the nearest
integer value, fractional parts are accumulated if revolution
in one direction continues, possibly causing a positional
error the next time the power is turned on.
(Condition 1) If K is less than 1, the “amount of movement
per rotation axis revolution (parameter No.
141) x K” contains a fractional part.
(Condition 2) Lp contains a fractional part.
Coordinates of the absolute--coordinate detector
Amount of
moveme n t
per rotation
axis revolution
Old reference position New reference position
Shift