Siemens Simatic S7-200 System Manual page 321

Network Read, Network Write
L
A
EN
D
TABLE
PORT
EN
TABLE
PORT
S
NETR
T
L
NETW
212 214
Byte
7
Offset
0 D A
1 Remote station address
2 Pointer to the data
3
4
5
6
7
8
22
Error Code
0
1
2
3
4
5
6
7
8
9
A-F
Figure 10-60
S7-200 Programmable Controller System Manual
C79000-G7076-C230-02
The Network Read instruction initiates a communication
operation to gather data from a remote device through the
NETR
specified port (PORT), as defined by the table (TABLE).
The Network Write instruction initiates a communication
operation to write data to a remote device through the specified
port (PORT), as defined by the table (TABLE).
NETW
Operands:
The NETR instruction can read up to 16 bytes of information
from a remote station, and the NETW instruction can write up to
16 bytes of information to a remote station. A maximum of eight
Table, Port
NETR and NETW instructions may be activated at any one time.
For example, you can have four NETRs and four NETWs, or
Table, Port
two NETRs and six NETWs in a given S7-200 programmable
logic controller.
215 216
Figure 10-60 defines the table that is referenced by the TABLE
parameter in the NETR and NETW instructions.
D Done (function has been completed):
A Active (function has been queued):
E Error (function returned an error):
0
E 0 Error code
Remote station address: the address of the PLC whose data is
to be accessed.
Pointer to the data area in the remote station: an indirect
pointer to the data that is to be accessed.
area in the
Data length: the number of bytes of data that is to be accessed
remote station in the remote station (1 to 16 bytes).
(I, Q, M, S, or V) Receive or transmit data area: 1 to 16 bytes reserved for the
data, as described below:
Data length
For NETR, this data area is where the values that are read
Data byte 0
from the remote station are stored after execution of the
Data byte 1
NETR.
For NETW, this data area is where the values to be sent to
the remote station are stored before execution of the NETW.
Data byte 15
No error
Time-out error; remote station not responding
Receive error; parity, framing or checksum error in the response
Offline error; collisions caused by duplicate station addresses or failed hardware
Queue overflow error; more than eight NETR/NETW boxes have been activated
Protocol violation; attempt execute NETR/NETW without enabling PPI+ in SMB30
Illegal parameter; the NETR/NETW table contains an illegal or invalid value
No resource; remote station is busy (upload or download sequence in process)
Layer 7 error; application protocol violation
Message error; wrong data address or incorrect data length
Not used; (reserved for future use)
Definition of TABLE for NETR and NETW
Table: VB, MB, *VD, *AC
Port: 0 to 1
0 = not done
0 = not active
0 = no error
Definition
Instruction Set
1 = done
1 = active
1 = error
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