Data Traffic And Db1 Parameter Assignment In A Point-To-Point Link - Siemens SIMATIC S5 Series Manual

Point-To-Point Link
2.2

Data Traffic and DB1 Parameter Assignment in a Point-To-Point Link

As in the case of the SINEC L1 LAN, data traffic is handled via send and receive mailboxes, which
are accessed by the PLC program via load and transfer operations (
Manual, Section 14.3).
The operating system of the CPU controls data transfer and stores this information in two
coordination bytes. The two bytes can be read and evaluated by the PLC program.
The structure of the coordination bytes is described in the next section.
For the point-to-point link, you determine the parameters in the "SL1:" (SINEC L1) of DB1. The
parameters for the point-to-point link correspond to the SINEC L1 parameters for the SI1 interface.
For the point-to-point link, the parameter "slave number" can also be set to "0" for the S5-95U
(master function, possible only at interface SI2). The partner is then identified as slave 1.
Caution: The parameter blocks for the ASCII driver (ASC:) and the computer link (RKT:) must
remain enclosed between comment characters! Only one communication possibility can ever be
parameterized for the second serial interface.
Please refer to the S5-90U/S5-95U System Manual, Section 14.2, for the parameter assignment of
DB1. In Section 2.4, you will find a complete program example of an S5-95U configured as a
master.
In Appendix A, you will find an overview of the DB1 parameter ranges.
Note
As long as the SI2 interface is parameterized as a point-to-point link, no other functions
are possible at the SI2 interface (e.g. programmer/operator panel).
2-6
S5-95U, Second Serial Interface
S5-90U/S5-95U System
EWA 4NEB 812 6095-02