Cyclic And Acyclic Communication Via Ctt2 - Siemens SINAMICS G110M Function Manual

7.5

Cyclic and acyclic communication via CTT2

Via CTT2 (Combined Transaction Type 2), both cyclical and acyclical communication is
performed via AS-i. Because only one channel is available (AS-i.DO1 master -> slave or AS-
i.DI3 slave -> master), a concurrent cyclical and acyclical data exchange is not possible.
The communication type (cyclical or acyclical) is always coded in the first byte in accordance
with the following table.
Table 7- 6
Code
(hex)
Cyclic communication
Access to analog values via DS140 ... DS147. See CP 343−2
/ CP 343−2 P AS−Interface master
(http://support.automation.siemens.com/WW/view/en/558165
7), Chapter 4
Acyclic communication - standard
10 hex
50 hex
90 hex
11 hex
51 hex
91 hex
Acyclic communication - manufacturer-specific
12 hex
52 hex
92 hex
13 hex
53 hex
93 hex
1D hex
5D hex
9D hex
Fieldbuses
Function Manual, 01/2016, FW V4.7 SP6, A5E34229197B AC
CTT2 commands
Explanation/meaning
Read request: Master -> slave
Read request OK: Slave -> master
Read request failed: Slave -> master
Write request: Master -> slave
Write request OK: Slave -> master
Write request failed: Slave -> master
Read request: Master -> slave
Read request OK: Slave -> master
Read request failed: Slave -> master
Write request: Master -> slave
Write request OK: Slave -> master
Write request failed: Slave -> master
Exchange request: Master -> slave
Exchange request OK: Slave -> master
Exchange request faulty: Slave -> master
Communication via AS-i - only for G110M
7.5 Cyclic and acyclic communication via CTT2
Followed by
4 bytes: PWE1, PWE2
4 bytes: PWE1, PWE2
2 bytes: Index, length
Index, data
1 byte: Standard error code (3 hex)
Index, length, data
1 byte: Standard error code (3 hex)
Index, length
Data
Fault object
Index, length, data
Fault object
Index, read length, write length, write
data
PKE, index, n-2 data
Fault object
211