Watson-Marlow MM440 - Manual (Page 150)

3 Functions Issue 10/06
MICROMASTER 440 Operating Instructions
150 6SE6400-5AW00-0BP0
In the address byte, information other than the node number is coded:
The individual bits in the address byte are assigned as follows:
= 1: Broadcast, address bits (No. 0 to 4) are not evaluated
= 0: No broadcast
7 6 5 4 3 2 1 0
STX LGE ADR 1. 2. n BCC
n net characters
Bit No.
Slave nodes No. 0 to 31
= 1: Mirror telegram
= 0: No mirror telegram
= 1: Special telegram (for an explanation, see below)
= 0: Standard; bits 0 to 6 are valid and must be evaluated
Fig. 3-40 Assignment of the address byte (ADR)
The master ensures cyclical telegram data transfer. The master addresses all of
the slave nodes one after the other with a task telegram. The addressed nodes
respond with a reply telegram. In accordance with the master-slave procedure, the
slave, after receiving the task telegram, must send the reply telegram to the master
before the master can address the next slave node.
The sequence of the addressed slave nodes can be specified, for example, by
entering the node numbers (ADR) in a circulating list (polling list) in the master. If it
is necessary to address several slaves in a faster cycle than the other slaves, their
node number can occur several times in the circulating list. A point-to-point link can
be implemented by means of the circulating list, in which case only one node is
entered into the circulating list.