Specifications

SIMATIC Instructions
9-178
S7-200 Programmable Controller System Manual
C79000-G7076-C233-01
Example of Network Read and Network Write
Figure 9-68 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 221
modules are used to control the case packers and a CPU 222 module equipped
with a TD 200 operator interface is used to control the diverter. Figure 9-68 shows
the network setup.
Case
Packer #2
CPU 221
Station 3
Case
Packer #3
CPU 221
Station 4
Case
Packer #4
CPU 221
Station 5
TD 200
Station 1
Case
Packer #1
CPU 221
Station 2
Diverter
CPU 222
Station 6
VB100
VW101
Control
Status
VB100
VW101
Control
Status
VB100
VW101
Control
Status
VB100
VW101
VB200 VB300
VB200 Receive buffer
Station 2
VB300 Transmit buffer
Station 2
Rcv
Buffers
Xmt
Buffers
Control
Status
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
VB230 Receive buffer
Station 5
VB210 Receive buffer
Station 3
VB221 Receive buffer
Station 4
VB330 Transmit buffer
Station
VB310 Transmit buffer
Station
VB320 Transmit buffer
Station 4
f e e e 0 g b t
Number of
cases packed
VB100
VB101
VB102
Control
Status
MSB
LSB
Figure 9-68 Example of NETR and NETW Instructions