Siemens SIMATIC NET CP 142-2, Manual, Page: 75 / 84

B8976111/02 AS-i Master Module CP 142-2
A-5
No. Function or call on the host interface (symbolic
representation) M1 Comment / Function implemented by /
Section
20 Status = Change_Slave_Address(Addr1, Addr2) X Change_slave_address / 4.2.1.14
21 Status = Set_Auto_Address_Enable X Set_auto_address / 4.2.1.12
22 Status = Get_Auto_Address_Enable X Read lists and flags / 4.2.1.16
23.1 Status, Resp = Cmd_Reset_ASI_Slave(Addr,
RESET)
- not implemented
23.2 Status, Resp = Cmd_Read_IO_Configuration(Addr,
CONF)
X Read slave I/Os / 4.2.1.24
23.3 Status, Resp =
Cmd_Read_Identification_Code(Addr, IDCOD)
X Read slave ID / 4.2.1.23
23.4 Status, Resp = Cmd_Read_Status(Addr, STAT) X Read slave status / 4.2.1.15
23.5 Status, Resp = Cmd_Read_Reset_Status(Addr,
STATRES)
X Read and reset slave status / 4.2.1.22
Symbols in column 3
Symbol Meaning
X Function exists
- Function does not exist
Relationship between the AS-i cycle time and the number of connected slaves
The following table shows how the AS-i cycle time depends on the number of connected slaves.
Number of slaves Maximum cycle time in ms
typical worst case
1 to 5 1.092 1.404
6 to 10 1.716 2.028
11 to 15 2.496 2.808
16 to 20 3.276 3.588
21 to 25 4.056 4.368
25 to 31 4.992 5.304
The "typical" times apply assuming that no frames are repeated, there are no management calls and
all slaves are synchronized.
If there are frame repetitions, the cycle time increases per frame repetition by 0.156 ms. If a
management phase occurs, the cycle time is also extended by 0.156 ms.
If the AS-i network is correctly installed, it is assumed that a maximum of one frame repetition will
occur per cycle. If it is also assumed that a management call occurs in this cycle, this results in the
worst case cycle time typ 0.312 ms)