Process Image - WAGO 750-651 Manual

2.1.1.8 Process Image

Using the module 750-651, a 6 byte input and output process image can be
transferred to the fieldbus coupler / controller via one logical channel. The
transfer of the data to be transmitted and the received data is made via 5
output and 5 input bytes (D0 ... D4). 1 Control byte (C) and 1 Status byte (S)
are used to control the floating data..
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 5 characters which have been received via interface can be stored in the
input bytes. The output bytes will contain the characters to be sent.
S
D0
D1
D2
D3
D4
TR
RA
IR
OL 0,
OL 1,
OL 2
0
WAGO-I/O-SYSTEM 750
Busklemmen
750-651 (/xxx-xxx) [TTY-Interface 20mA Current Loop] • 17
Input data
Status byte
Input byte 0
Input byte 1
Input byte 2
Input byte 3 *), **)
Input byte 4 **)
*) with variations with 4 Data bytes, **) with variations with 5 Data bytes
Bit 7 Bit 6 Bit 5
0 OL 2 OL 1
Transmit request
Receive acknowledge
Initialization request
Output length (number of characters to be sent, which have been stored in the
output bytes)
Constant value must always be 0.
Output data
C Control byte
D0 Output byte 0
D1 Output byte 1
D2 Output byte 2
D3 Output byte 3 *), **)
D4 Output byte 4 **)
Control byte
Bit 4 Bit 3 Bit 2
OL 0 0
Process Image
Bit 1 Bit 0
IR RA TR