Siemens SIMATIC S7-200 System Manual page 97

Case Packer #1 Case Packer #2
Station 2 Station 3
VB100 Control VB100
VW101 Status VW101
VB100 f e e e 0
VB101 Number of
VB102 cases packed
t Out of butter tubs to pack; t=1, out of butter tubs
b Box supply is low; b=1, must add boxes in the
next 30 minutes
g Glue supply is low; g=1, must add glue in the next 30 minutes
eee error code identifying the type of fault experienced
f Fault indicator; f=1, the case packer has detected an error
Figure 6-6 Example of the Network Read and Network Write Instructions
Figure 6-7 shows the receive buffer (VB200) and transmit buffer (VB300) for accessing the data in
station 2. The S7-200 uses a Network Read instruction to read the control and status information
on a continuous basis from each of the case packers. Each time a case packer has packed 100
cases, the diverter notes this and sends a message to clear the status word using a Network Write
instruction.
Receive Buffer for reading from
Case Packer #1
7
D
VB200
Remote station address = 2
VB201
VB202
VB203
VB204
Remote station = (&VB100)
VB205
VB206
VB207
VB208
VB209
Figure 6-7 Sample TBL Data for the Network Read/Write Example
Case Packer #3
Station 4
Control VB100 Control
Status VW101 Status
Control
g b t
Status MSB
LSB
0
A E 0 Error Code
Pointer to the
data area
in the
Data length = 3 bytes
Control
Status (MSB)
Status (LSB)
S7-200 Instruction Set
Case Packer #4 Diverter
Station 5 Station 6
VB100 Control
VB200
VW101 Status
VB200 Receive buffer
Station 2
VB210 Receive buffer
Station 3
VB220 Receive buffer
Station 4
VB230 Receive buffer
Station 5
Transmit Buffer for clearing the count of
Case Packer #1
7
D
VB300
Remote station address = 2
VB301
VB302
VB303
VB304
Remote station = (&VB101)
VB305
VB306
VB307
VB308
Chapter 6
TD 200 Station 1
Rcv VB300 Xmt
Buffers Buffers
VB300 Transmit buffer
Station 2
VB310 Transmit buffer
Station
VB320 Transmit buffer
Station 4
VB330 Transmit buffer
Station
0
A E 0 Error Code
Pointer to the
data area
in the
Data length = 2 bytes
0
0
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