Mitsubishi Melsec-Q QD75D1, User Manual

Page: 35 / 858

1 - 11
MELSEC-Q
1 PRODUCT OUTLINE
(a) In the system shown in Fig. 1.4, the movement amount per pulse,
command pulse frequency, and the deviation counter droop pulse amount
are determined as follows:
1) Movement amount per pulse
The movement amount per pulse is determined by the worm gear lead,
deceleration ratio, and the pulse encoder resolution.
The movement amount, therefore, is given as follows: (Number of
pulses output) × (Movement amount per pulse).
L
A =
R
×
n
[mm/pulse]
2) Command pulse frequency
The command pulse frequency is determined by the speed of the
moving part and movement amount per pulse:
V
Vs =
A
[pulse/s]
3) Deviation counter droop pulse amount.
The deviation counter droop pulse amount is determined by the
command pulse frequency and position loop gain.
Vs
ε
=
K
[pulse]
(b) The QD75 allows the user to select from the following four units as the unit
used by positioning commands to any of the axes (1 to 4, if the module
supports four axes): mm, inch, degree, and pulse.
The unit selected for one axis may differ from the unit selected for another
axis.
When such data as the acceleration/deceleration time, positioning speed,
and positioning address are correctly set in consideration of the chosen
unit, the QD75 can calculate the number of pulses required for a movement
amount to the target positioning address and execute the positioning by
outputting a pulse train that includes the calculated number of pulses.