Siemens Simatic S7-200 System Manual page 322

Instruction Set
Example of Network Read and Network Write
Figure 10-61 shows an example to illustrate the utility of the NETR and NETW instructions.
For this example, consider a production line where tubs of butter are being filled and sent to
one of four boxing machines (case packers). The case packer packs eight tubs of butter into
a single cardboard box. A diverter machine controls the flow of butter tubs to each of the
case packers. Four CPU 212 modules are used to control the case packers and a CPU 214
module equipped with a TD 200 operator interface is used to control the diverter.
Figure 10-61 shows the network setup.
Case
Packer #1
CPU 212
Station 2
Control
VB100
Status
VW101
f e e e 0 g b t
VB100
VB101
cases packed
VB102
f fault indicator; f=1, the case packer has detected an error
g glue supply is low; g=1, must add glue in the next 30 minutes
b box supply is low; b=1, must add boxes in the next 30 minutes
t out of butter tubs to pack; t=1, out of butter tubs
eee error code identifying the type of fault experienced
Figure 10-61
10-134
Case Case
Packer #2 Packer #3
CPU 212 CPU 212
Station 3 Station 4
Control Control
VB100 VB100
Status Status
VW101 VW101
VB200
VB210
Control
VB220
Status
Number of
MSB
VB230
LSB
Example of NETR and NETW Instructions
Case
Packer #4 Diverter
CPU 212 CPU 214
Station 5 Station 6
Control
VB100
VB200
Rcv
Buffers
Status
VW101
Receive buffer VB300
Station 2
Receive buffer VB310
Station 3
Receive buffer VB320
Station 4
Receive buffer VB330
Station 5
S7-200 Programmable Controller System Manual
C79000-G7076-C230-02
TD 200
Station 1
VB300
Xmt
Buffers
Transmit buffer
Station 2
Transmit buffer
Station
Transmit buffer
Station 4
Transmit buffer
Station