Specifications

Chapter 11 Selection
11–5
(4) Absolute position repeatability : ∆εa
This is the precision outline that affects the absolute position system machine, and expresses the
repeatability of the position before the power was shut off and the position when the power is
turned on again.
With the single motor unit, the precision is 1 to 2 times the theoretic precision ∆ε. Note that the
absolute position repeatability ∆εa is the difference from when the power was turned off last and
returned on. This error is not cumulated.
Table 11-4 shows the approximate precision at the motor end of each motor series. Obtain the
precision at the motor end during actual machining by adding the machine precision to the value in the
table.
Table 11-4 Precision by motor series
Motor series
Control
resolution RNG
(pulse/rev)
Theoretic
precision
∆ε
Positioning
precision
∆εp
Surface precision
∆εv
Absolute position
repeatability
∆εa
HS-SF 100000
10∆ε to 20∆ε
HS-RF 100000
10∆ε to 20∆ε
HS-MF 8000
∆
S
RNG
∆ε to 2∆ε
30∆ε to 40∆ε
∆ε to 2∆ε
(Note) The expressions in the table indicate the approximate accuracy at the motor end. The accuracy at the machine end
during actual machining is obtained by adding this to the machine accuracy.