Communications Instructions; Network Read And Network Write Instructions - Siemens Simatic S7-200 System Manual

S7-200 Programmable Controller System Manual

Communications Instructions

Network Read and Network Write Instructions

The Network Read instruction (NETR) initiates a communications
operation to gather data from a remote device through the specified
port (PORT), as defined by the table (TBL). The Network Write
instruction (NETW) initiates a communications operation to write
data to a remote device through the specified port (PORT), as
defined by the table (TBL).
Error conditions that set ENO = 0:
H 0006 (indirect address)
H If the function returns an error and sets the E bit of table status byte (see
Figure 6-4)
The Network Read instruction can read up to 16 bytes of information
from a remote station, and the Network Write instruction can write up
6
to 16 bytes of information to a remote station.
You can have any number of Network Read and Network Write
instructions in the program, but only a maximum of eight Network
Read and Network Write instructions can be activated at any one
time. For example, you can have 4 Network Read and 4 Network
Write instructions, or 2 Network Read and 6 Network Write
instructions, active at the same time in a given S7-200.
You can use the Network Read/Network Write Instruction Wizard to configure the counter. To start the
Network Read/Network Write Instruction Wizard, select the Tools > Instruction Wizard menu command
and then select Network Read/Network Write from the Instruction Wizard window.
Instruction
Wizard
Table 6-9
Inputs/Outputs
TBL
PORT
74
Valid Operands for the Network Read and Network Write Instructions
Data Type Operands
BYTE VB, MB, *VD, *LD, *AC
BYTE Constant for CPU 221, CPU 222, CPU 224:
for CPU 226 and CPU 226XM:
0
0 or 1