
System philosophy
HARDWARE REFERENCE MANUAL
33
Revi
si
on 3.0
Example 3
fig. 21
The
SERVO_PERIOD
has a value of 2ms and the motion
sequence is executed every 2.0ms.
Servo period rules
The number of axes and MECHATROLINK-II devices in the
Trajexia system determines the value of the
SERVO_PERIOD
system parameter.
There are 3 types of MECHATROLINK-II devices that are
supported by the TJ1-MC__ units:
•
Servo Drivers.
The TJ1-MC__ considers Servo Drivers as axes.
•
Frequency inverters.
The TJ1-MC__ does not consider frequency inverters as axes.
•
I/O units and slice bus couplers.
The TJ1-MC__ does not consider I/O units (analog and digital,
counter and pulse) and slice bus couplers as axes.
You must obey the most restrictive rules when you set the
SERVO_PERIOD
parameter. An incorrect value of the
SERVO_PERIOD
parameter results in an incorrect detection of the
MECHATROLINK-II devices.
The most restrictive rules are given in the tables below. For each
unit the table lists the maximum number of devices the unit can
control at the given
SERVO_PERIOD
setting.
/i
CPU task 1
Motion sequence
Low priority task (0,1,2,3...)
CPU task 2
High priority task (13,14)
CPU task 3
LED refresh
High priority task (13,14)
CPU task 4
Communication
2ms
SERVO_PERIOD
TJ1-MC16
TJ1-MC04
TJ1-ML16
TJ1-ML04
0.5 ms
8 axes
5 axes
4 devices
4 devices
4 non-axis
devices
4 non-axis
devices
1.0 ms
16 axes
5 axes
8 devices
4 devices
8 non-axis
devices
8 non-axis
devices
I51E-EN-03.book Seite 33 Donnerstag, 28. Juni 2007 1:05 13