C1120 S5 to II/O-Lightbus Interface
Beckhoff II/O-Lightbus System
Page 18 of 52
Version 2.1
Date 27.06.97
Fast Communications Channel
If the S5 is run in multi-processor mode, one CPU can be assigned the fast communications
channel in order to improve process image synchronisation.
The fast communications channel works only with a selection of peripheral modules which
are given the identification codes “ SA” or “ SE” on the IO List. The range of values for the
entries is from 128 to 255. The priority for fast communication is lower than for single box
mode and higher than for cyclical operation.
To activate the channel, you must enter the option “ 1” in the Activate field in the menu
option Edit Configuration.
Handling of Fast Communications Channel
The fast communications channel is operated with a handshake procedure.
The sequence for the individual steps is described below.
S5
C1120
1.)
Writes a 1 to the cell
Page + 1023 (Interrupt)
2.)
Polls the cell Page + 1022 while cell
equals 0
Process image for fast
communications channel is updated
3.)
-” -
Process image is updated,
Acknowledged by writing a 1 to the
cell Page + 1022
4.)
Writes a 0 to the cell
Page + 1023 (Interrupt)
5.)
Polls the cell Page + 1022 while cell
equals 1
Writes a 0 to the cell
Page + 1022
