Watson-Marlow MM420 - Manual (Page 105)

Issue 10/06 3 Functions
MICROMASTER 420 Operating Instructions
6SE6400-5AA00-0BP0 105
Example of configuration
1 3 5 7 21 0
0
1
3
5
0
7
21
1
3
5
0
1
0
1
7
21
Master
Circulating list
in the master
MICROMASTER with the addresses 0, 1, 3, 5, 7 and 21
Nodes 0 and 1 are signalled twice as often as others
Fig. 3-34 Circulating list (Example of configuration)
The length of a cycle time is determined by the time needed for the sequential
occurrence of data exchange with the individual nodes.
Cycle time
0 0 1 1 0 0 t
Telegram run time for reply from node 1
Reply delay time from node 1
Telegram run time for task for node 1
Processing time in the master
Fig. 3-35 Cycle time
Due to inconstant reply delay and processing times, the cycle time is not fixed.
The STX start character (= 02 hexadecimal) by itself is not sufficient for the slaves
to clearly identify the start of a telegram because the bit combination
02/hexadecimal can also occur in the net characters. For this reason, a no-
character start interval of at least 2 character run-times before the STX is specified
for the master. The start interval is part of the task telegram.