Communications Instructions; Network Read And Network Write Instructions - Siemens SIMATIC S7-200 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 6-5)
The Network Read instruction can read up to 16 bytes of
information from a remote station, and the Network Write
instruction can write up 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 6-10 Valid Operands for the Network Read and Network Write Instructions
Inputs/Outputs
TBL
PORT
Data Type Operands
BYTE VB, MB, *VD, *LD, *AC
BYTE Constant
S7-200 Instruction Set
for CPU 221, CPU 222, CPU 224:
for CPU 224XP, CPU 226:
Chapter 6
0
0 or 1
81