Omron TJ2-MC64 - PROGRAMMING Programming Manual page 266

Examples and tips
Parameter Pn202 is the electronic gear ratio denominator (G1). Parameter
Pn203 is the electronic gear ratio numerator (G2). The servo motor rotates
using the value of the position command signal sent by the TJ2-MC64,
multiplied by the electronic gear (Pn202, Pn203). On the output (servo
motor) side, the signal is expressed in number of encoder pulses. For more
information on Servo Driver parameters Pn202 and Pn203, see the Sigma-II
Servo Driver manual.
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:
Pn202
.
UNITS =
Pn203
where y is the number of encoder counts and x is the amount in user units.
Example 1
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 encoder_counts
.
UNITS =
.
Pn203 1 motor_revolution 1 machine_revolution
13
.
2 10 encoder_counts
360 degree
PROGRAMMING MANUAL
y·encoder _ counts
x·user _ units
13 .
encoder_counts
.
o
. .
10 motor_revolution 1 machine_revolution
.
o
360
Trajexia
MOVE(x)
reference_units,
the minimum unit you can set
internally to the servo
driver
* UNITS
M
13-bit
incremental
1:10 Gear
encoder
=
fig. 18
Servo Driver
encoder_counts,
the ultimate minimum distance
you can recognize and
depends on the encoder
*Pn202/Pn203
encoder
fig. 19
Full turn = 360
Motor
260