Omron trajexia CJ1W-MCH72 Operation Manual page 298

How-to's
5-1-3-2 Example 1
The UNITS axis parameter effectively expresses the ratio between user units
that the user wants to use in the program and the position sent to the Servo
Driver via the MECHATROLINK-II bus. Taking the electronic gear setting into
account, the equation expressing the relation between user units, the UNITS
parameter, parameters Pn202 and Pn203, encoder pulses and mechanical
measurement units is:
where y is the number of encoder counts and x is the amount in user units.
M
13-bit
incremental
1:10 Gear
encoder
The mechanical system consists of a simple rotary table. A servo motor with
13-bit incremental encoder is used. The gear ratio of the gearbox is 1:10.
The desired user units are degree of angle. This system can be described with
the following equations:
.
1 motor_revolution = 2
.
10 motor_revolution = 1 machine_cycle
.
1 machine_cycle = 360
The combination of these equations results in:
13
Pn202 2
.
UNITS =
.
Pn203 1 motor_revolution 1 machine_revolution
13
.
2 10 encoder_counts
360 degree
And therefore:
From this equation, we can derive the values for Pn202, Pn203 and UNITS,
given the following restrictions and recommendations:
Pn202 y·encoder _ counts
.
UNITS =
Pn203 x·user _ units
13 .
encoder_counts
.
o
. .
encoder_counts 10 motor_revolution
.
Pn202
2
.
UNITS =
Pn203
Section 5-1
Full turn = 360
.
1 machine_revolution
o
360
13
.
10
360
=
287