System philosophy
HARDWARE REFERENCE MANUAL
25
Revision 5.0
2.4.3
Motion buffers
Motion buffers are the link between the BASIC commands and the Axis
control loop. When a BASIC motion command is executed, the command is
stored in one of the buffers. During the next motion sequence, the profile
generator executes the movement according to the information in the buffer.
When the movement is finished, the motion command is removed from the
buffer. The TJ2-MC__ can have up to 64 motion buffers, which is defined by
the
LIMIT_BUFFERED
system parameter.
2.4.4
Communication
A set of BASIC communication commands are used to configure the
communications. When the Trajexia is a communication slave (as in the
PROFIBUS communication) it is only necessary to configure the
communication in an initial task. The values are exchanged from the
configured global variables in a transparent way. When the Trajexia is a
communications master, the BASIC communication commands are used to
write and read.
2.4.5
Peripherals
All inputs and outputs are used with the set of parameters (
IN
,
OP
,
AIN
,
AOUT
). The inputs and outputs are automatically detected and mapped in
Trajexia. Inverters are considered a peripheral device and have a set of
BASIC commands to control them. Various MECHATROLINK-II input and
output modules can be connected to a TJ1-ML__ unit. Various EtherCAT
input and output modules can be connected to a TJ1-ECT__ unit.
2.5
Cycle time
fig. 17
All processes in the Trajexia system are based on the cycle time. The cycle
time is divided into four CPU slots:
•
250
μ
s time intervals for a
SERVO_PERIOD
of 0.25, 0.5 and 1.0ms
•
500
μ
s time intervals for a
SERVO_PERIOD
of 2.0ms
The processes that can be carried out in each time interval depends on the
SERVO_PERIOD
that is set.
Cycle time = 1ms
250
μ
s
1
2
3
4