Example Of Network Read And Network Write - Siemens SIMATIC S7-200 System Manual

SIMATIC Instructions

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 #1
CPU 221
Station 2
Control
VB100
Status
VW101
f e e e 0 g b t
VB100
VB101
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 9-68
9-182
Case Case
Packer #2 Packer #3
CPU 221 CPU 221
Station 3 Station 4
Control Control
VB100 VB100
Status Status
VW101 VW101
Control
Status
Number of
MSB
cases packed
LSB
Example of NETR and NETW Instructions
Case
Packer #4 Diverter
CPU 221 CPU 222
Station 5 Station 6
Control
VB100
VB200
Status
VW101
VB200 Receive buffer VB300
Station 2
VB210 Receive buffer VB310
Station 3
VB221 Receive buffer VB320
Station 4
VB230 Receive buffer VB330
Station 5
S7-200 Programmable Controller System Manual
TD 200
Station 1
VB300
Rcv Xmt
Buffers Buffers
Transmit buffer
Station 2
Transmit buffer
Station
Transmit buffer
Station 4
Transmit buffer
Station
A5E00066097-02