Communications
configuring
System- and communication configuring D7-SYS - SIMADYN D
3-235
Edition 12.2003
1. Telegram received from the display device (using @DIS)
2. The receive telegram contents are evaluated (using process data- and
binary value blocks)
3. The transmit telegram contents are prepared (using the process data-
and binary value blocks)
4. Telegram is transmitted to the display device (using @DIS in the next
sampling time)
The subordinate USS coupling operates asynchronously (bus circulating
time).
3.20.4.1 Computation
times
The computation times of the function blocks are independent of that of
the application. As a display device system can process between one
and 31 stations, the computation time differs.
The computation times of the function blocks for a display device as well
as the additional computation time for each additional display device in
µs are shown in the following tables.
@DIS
DISAx
DISSx
DISA1B
DISS1B
DISS11
One
display
device
360 20 50 20 30 30
Each additional display
device
150
0 0 0 0 0
Table 3-72
Computation time in µs
The computation time of a process data setpoint block can be several
sampling times longer for certain operations (e. g. saving a value in the
change memory).
3.20.4.2
Data transfer times
The response times when displaying data at an OP2 should not exceed
300 milliseconds, otherwise this will appear too slow for the operator.
This time is significantly influenced by the USS bus circulating time and
the sampling time in which the blocks are configured. Thus, it is
recommended, that both times are kept well below 300 milliseconds.
An overview of the bus circulating time as a function of the configured
baud rate, configured number of stations and transferred messages is
shown in the following table:
Baud rate
(kbaud)
Number of
stations
Bus circulating time
without messages
(ms)
Max. message run time
(ms)
187,5 1
10
22
28 280
30 300
General
General
