64
○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○
© Systeme Lauer GmbHAEG250PX-Expander driver
○○○○○○○
○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○
○○
D
Structure of the write cycle:
PCS PROGRAMMABLE CONTROLLER
WRITE N BYTES →
← OK / ERROR
...
(REPETITION CORRESPONDING TO THE DATA FIELD)
...
WRITE N BYTES →
← OK / ERROR
WRITE DW3 →
← OK / ERROR
D3.4 PCS - PLC effective response times
The response time of the protocol depends extensively on the tasks executed in the
PCS. If variables are displayed or even processed, then the communication cycle
time is essentially higher than with text without variables. Also, the transfer of the
message bit area and LED words influences this time. Limit these transfers. You
can do this also in the running operation, e.g. to realize a key-driven jog operation.
The response is likewise greatly dependent on the programmable controller scan
time since the AEG-programmable controller processes the communication at the
end of a cycle.
The following table presents a reference for the speed of communication. The so-
called key → LED time is measured. That means the time in which a key is
transferred to the programmable controller and an LED is set in the PCS. This time
is made up of 2 communication cycles and a programmable controller scan time.
The response, i.e. the time a key is signaled in the programmable controller is
only half the indicated time! The measurements were made with a PCS950 and a
low programmable controller scan time burden.
Key → LED [milliseconds]
Baud rate Variable Time [ms]
19200 NONE 550
9600 NONE 700
19200 8 flush 650
9600 8 flush 800
19200 7 non-flush 750
9600 7 non-flush 950
The programmable controller scan time must be added to the time value which is
an average value. The variables are not consecutively stored but stored with at
least one word distance in between. This is the worst case since for each variable
a write or read order must be sent. For a fast communication, you should make
sure that the variables are located one after another in the data word. Then, several
variables can be sent in a write and/or read order.
Communication
To Next Page
Loading...
Need help?
General