Process Image - WAGO I/O-SYSTEM 750 Manual

12 • 750-653 (/xxx-xxx) [Serial Interface RS 485]

Process Image

Attention
The data transmission takes place at 9600 baud. 1 startbit, 8 databits and 1
stopbit will be transmitted. No parity is available. The drivers are high
ohmic. The control of data is made by the user software.
Attention
The interface module can be used for bus connections as well as for point to
point connections. With bus connections, modules that are not connected to
the power supply can also be wired. They do not disturb the bus connection.
A
B
TxD
RxD
750-653
Point to point connection
Fig. 2.1.1-4: Connection of the RS 485 interface module
2.1.1.8 Process Image
Using the module 750-653, a 6 byte input and output process image can be
transferred to the fieldbus coupler / controller via one logical channel. The
data sent and received are stored in up to 5 output and input bytes (D0 ... D4).
One control byte (C) and one status byte (S) are used to control the data flow.
Attention
The representation of the process data of some I/O modules or their variations
in the process image depends on the fieldbus coupler/-controller used. Please
take this information as well as the particular design of the respective
control/status bytes from the section "Fieldbus Specific Design of the Process
Data" included in the description concerning the process image of the
corresponding coupler/controller.
Up to five characters which have been received by interface can be stored in
the input bytes. The output bytes will contain the characters to be sent.
13 14
Receiver
C
D
__
R
TxD
__
Transmitter
RxD
R
M M
S S
R = 150 W
13 14
A
C
B
Termination D
__
TxD TxD
R
__
RxD RxD
Transmitter
and receiver
M M
S S
750-653
Transmitter
and receiver
R = 150 W
Bus connection
WAGO-I/O-SYSTEM 750
I/O Modules
Termination
R
Transmitter
and receiver
g065302e