3. Installation
3-22
Festo P.BE-SPC11-SYS-ASI -EN en 0203NH
Address assignment
An AS-Interface master assigns 4 bits (a nibble) to each stan-
dard slave. Communication between the master and the stan-
dard slave takes place via these 4 bits (D0...D3). In the case
of standard slaves with I/O code 7
H
input data (I1...I4) and
output data (O1...O4) are transmitted bi-directionally via
these 4 bits.
Example of addre ss assignment with control unit
SF3 with AS-Interface master from Festo
–I/Ocode:7
H
– Slave address: #4
PLC byte: #18
0123 0123
12035647
0123 0123
0123 0123
0123 0123
17
16
PLC byte
(example)
18
....
Slave #1
Slave #3
....
31
....
Slave #2
Slave #5
Slave #4
Slave #31
Slave #30
0123 0123
12035647
0123 0123
0123 0123
0123 0123
17
16
18
....
Slave#1
Slave#3
....
31
....
Slave #2
Slave#5 Slave #4
Slave #31 Slave #30
3
3
21
PLC byte
(example)
1 Input byte
2 Output byte
3 Assigned addresses with I/O code 7
H
Fig. 3/10: Example of address assignment with control unit SF3