Mitsubishi Electric FR-A700 EC, Инструкция по эксплуатации

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Position control by vector control Parameter
6 - 138
Relationship between position resolution
Δ
l and overall accuracy
Since overall accuracy (positioning accuracy of machine) is the sum of electrical error and
mechanical error, normally take measures to prevent the electrical system error from affecting
the overall error. As a guideline, refer to the following relationship.
Δε
: positioning accuracy
Examples
쑴
Setting example 1:
The travel per pulse is
Δ
l = 0.01 mm in a drive system where the ballscrew pitch PB = 10
(mm) and the reduction ratio 1/n = 1 and the electronic gear ratio is
Δ
s = 10 (mm) when the
number of feedback pulses Pf = 4000 (pulse/rev).
According to the following expression,
Therefore, set "4" in Pr. 420 and "1" in Pr. 421 .
Setting example 2 :
Find the internal command pulse frequency of the dedicated motor rated speed.
Note that the command pulse scaling factor Pr. 420/Pr. 421 = 1.
Assuming that the number of encoder pulses is 2048 (pulses/rev) (feedback pulse Pf = 2048
× 4),
Therefore, the internal command pulse frequency is 204800 (pps).
쑶
Δ
l
Δ
s
Pf
-------
Pr. 420
Pr. 421
-------------------
×
=
Pr. 420
Pr. 421
-------------------
Δ
l
Pf
Δ
s
-------
×
0.01
4000
10
-------------
×
4
1
--- =
=
=
fo 2048 4
×
No
60
-------
×
Pr. 421
Pr. 420
-------------------
×
204800
=
=
Δ
l
1
5
--- to
1
10
------
( )
Δε × <