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CHAPTER2 PROFIBUS Unit
2-6
Sequencer (master station) settings
The master station sequencer (or PLC) in the PROFIBUS system can make line tests on
the slave station. Use this function to check whether or not the controller is identified as
a slave station on the PROFIBUS system before starting any actual work. Refer to the
instruction manual for the master station sequencer (PLC) for detailed information.
2-6-1
Exchanging data with the controller
To ensure that data is exchanged correctly and safely between the master station PLC
and controller, create a PLC program for the master station that takes the following
points into account.
■
Put network status information into the PLC program as input conditions to help it
handle problems in the network itself. (See the master PLC instruction manual for
ways to enter status information.)
■
When a network error is detected on the controller, the controller stops operating and
turns the servo off. Also all I/O input from the PROFIBUS are recognized as being off
during the error. The I/O inputs are automatically restored as the network recovers
from the error but the servo remains turned off. So to restore operation, [Eergency
stop must be canceled and the servo restore command (SERVO) must be run.
■
The controller always keeps the servo off right after its power is turned on. To operate
the robot, cancel emergency stop and run the servo restore command (SERVO).
■
The controller is resetting (initializing) itself immediately after the controller power
is turned on, so do not perform communications right away. The END output turns on
when the controller starts up normally and communication is allowed, so first check
that the END output is on before inputting commands to the controller.
(See "2-8-1 Right after controller power turns on".)
