Fieldbus Controller 750-841 • 51
Process Image
3.1.4.3 Fieldbus specific Process Data Architecture for MODBUS/TCP
With some I/O modules, the structure of the process data is fieldbus specific.
In the case of an Ethernet TCP/IP controller, the process image uses a word structure (with word alignment). The internal mapping method for data greater than one byte conforms to the Intel format.
The following section describes the process image for various WAGO750 I/O modules when using an Ethernet TCP/IP controller.
Note
Depending on the specific position of an I/O module in the fieldbus node, the process data of all previous byte or bit-oriented modules must be taken into account to determine its location in the process data map.
3.1.4.3.1 Digital Input Modules
Digital input modules supply one bit of data per channel to specify the signal state for the corresponding channel. These bits are mapped into the Input Process Image.
When analog input modules are also present in the node, the digital data is always appended after the analog data in the Input Process Image, grouped into bytes.
Some digital modules have an additional diagnostic bit per channel in the Input Process Image. The diagnostic bit is used for detecting faults that occur (e.g., wire breaks and/or short circuits).
1 Channel Digital Input Module with Diagnostics
750-435
Bit 7 |
Bit 6 |
Bit 5 |
Bit 4 |
Bit 3 |
Bit 2 |
Bit 1 |
Bit 0 |
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Diagnostic |
Data bit |
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bit |
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DI 1 |
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S 1 |
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2 Channel Digital Input Modules
750-400, -401, -405, -406, -410, -411, -412, -427
Bit 7 |
Bit 6 |
Bit 5 |
Bit 4 |
Bit 3 |
Bit 2 |
Bit 1 |
Bit 0 |
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Data bit |
Data bit |
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DI 2 |
DI 1 |
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Channel |
Channel |
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2 |
1 |
WAGO-I/O-SYSTEM 750 ETHERNET TCP/IP
52 • Fieldbus Controller 750-841
Process Image
2 Channel Digital Input Modules with Diagnostics
750-419, -424, -425
Bit 7 |
Bit 6 |
Bit 5 |
Bit 4 |
Bit 3 |
Bit 2 |
Bit 1 |
Bit 0 |
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Diagnostic |
Diagnostic |
Data bit |
Data bit |
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bit S 2 |
bit S 1 |
DI 2 |
DI 1 |
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Channel 2 |
Channel 1 |
Channel |
Channel |
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2 |
1 |
2 Channel Digital Input Module with Diagnostics and Output Process Data
750-418
The 750-418 digital input module supplies a diagnostic and acknowledge bit for each input channel. If a fault condition occurs, the diagnostic bit is set. After the fault condition is cleared, an acknowledge bit must be set to reactivate the input. The diagnostic data and input data bit is mapped in the Input Process Image, while the acknowledge bit is in the Output Process Image.
Input Process Image
Bit 7 |
Bit 6 |
Bit 5 |
Bit 4 |
Bit 3 |
Bit 2 |
Bit 1 |
Bit 0 |
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Diagnostic |
Diagnostic |
Data bit |
Data bit |
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bit S 2 |
bit S 1 |
DI 2 |
DI 1 |
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Channel 2 |
Channel 1 |
Channel |
Channel |
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2 |
1 |
Output |
Process |
Image |
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Bit 7 |
Bit 6 |
Bit 5 |
Bit 4 |
Bit 3 |
Bit 2 |
Bit 1 |
Bit 0 |
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Acknowled |
Acknowled |
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gement bit |
gement bit |
0 |
0 |
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Q 2 |
Q 1 |
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Channel 2 |
Channel 1 |
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4 Channel Digital Input Modules
750-402, -403, -408, -409, -414, -415, -422, -423, -428
Bit 7 |
Bit 6 |
Bit 5 |
Bit 4 |
Bit 3 |
Bit 2 |
Bit 1 |
Bit 0 |
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Data bit |
Data bit |
Data bit |
Data bit |
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DI 4 |
DI 3 |
DI 2 |
DI 1 |
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Channel |
Channel |
Channel |
Channel |
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4 |
3 |
2 |
1 |
8 Channel Digital Input Modules
750-430, -431
Bit 7 |
Bit 6 |
Bit 5 |
Bit 4 |
Bit 3 |
Bit 2 |
Bit 1 |
Bit 0 |
Data bit |
Data bit |
Data bit |
Data bit |
Data bit |
Data bit |
Data bit |
Data bit |
DI 8 |
DI 7 |
DI 6 |
DI 5 |
DI 4 |
DI 3 |
DI 2 |
DI 1 |
Channel |
Channel |
Channel |
Channel |
Channel |
Channel |
Channel |
Channel |
8 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
WAGO-I/O-SYSTEM 750 ETHERNET TCP/IP
Fieldbus Controller 750-841 • 53
Process Image
3.1.4.3.2 Digital Output Modules
Digital output modules use one bit of data per channel to control the output of the corresponding channel. These bits are mapped into the Output Process Image.
When analog output modules are also present in the node, the digital image data is always appended after the analog data in the Output Process Image, grouped into bytes.
1 Channel Digital Output Module with Input Process Data
750-523
Input Process Image
Bit 7 |
Bit 6 |
Bit 5 |
Bit 4 |
Bit 3 |
Bit 2 |
Bit 1 |
Bit 0 |
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Status bit |
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not used |
„Manual |
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Operatio |
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n“ |
Output |
Process |
Image |
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Bit 7 |
Bit 6 |
Bit 5 |
Bit 4 |
Bit 3 |
Bit 2 |
Bit 1 |
Bit 0 |
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controls |
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not used |
DO 1 |
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Channel |
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1 |
2 Channel Digital Output Modules
750-501, -502, -509, -512, -513, -514, -517, -535
Bit 7 |
Bit 6 |
Bit 5 |
Bit 4 |
Bit 3 |
Bit 2 |
Bit 1 |
Bit 0 |
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controls |
controls |
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DO 2 |
DO 1 |
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Channel |
Channel |
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2 |
1 |
2 Channel Digital Input Modules with Diagnostics and Input Process Data
750-507, -522
The 750-507 and 750-522 digital output modules have a diagnostic bit for each output channel. When an output fault condition occurs (i.e., overload, short circuit, or broken wire), a diagnostic bit is set. The diagnostic data is mapped into the Input Process Image, while the output control bits are in the Output Process Image.
Input Process Image
Bit 7 |
Bit 6 |
Bit 5 |
Bit 4 |
Bit 3 |
Bit 2 |
Bit 1 |
Bit 0 |
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Diagnosti |
Diagnosstic |
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c bit S 2 |
bit S 1 |
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Channel 2 |
Channel 1 |
WAGO-I/O-SYSTEM 750 ETHERNET TCP/IP
54 • Fieldbus Controller 750-841
Process Image
Output Process Image
Bit 7 |
Bit 6 |
Bit 5 |
Bit 4 |
Bit 3 |
Bit 2 |
Bit 1 |
Bit 0 |
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controls |
controls |
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DO 2 |
DO 1 |
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Channel |
Channel |
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2 |
1 |
750-506
The 750-506 digital output module has 2-bits of diagnostic information for each output channel. The 2-bit diagnostic information can then be decoded to determine the exact fault condition of the module (i.e., overload, a short circuit, or a broken wire). The 4-bits of diagnostic data are mapped into the Input Process Image, while the output control bits are in the Output Process Image.
Input Process Image
Bit 7 |
Bit 6 |
Bit 5 |
Bit 4 |
Bit 3 |
Bit 2 |
Bit 1 |
Bit 0 |
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Diagnosti |
Diagnosti |
Diagnosti |
Diagnosti |
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c bit S 3 |
c bit S 2 |
c bit S 1 |
c bit S 0 |
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Channel 2 |
Channel 2 |
Channel 1 |
Channel 1 |
Output Process Image |
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Bit 7 |
Bit 6 |
Bit 5 |
Bit 4 |
Bit 3 |
Bit 2 |
Bit 1 |
Bit 0 |
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controls |
controls |
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not used |
not used |
DO 2 |
DO 1 |
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Channel |
Channel |
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2 |
1 |
4 Channel Digital Output Modules
750-504, -516
Bit 7 |
Bit 6 |
Bit 5 |
Bit 4 |
Bit 3 |
Bit 2 |
Bit 1 |
Bit 0 |
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controls |
controls |
controls |
controls |
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DO 4 |
DO 3 |
DO 2 |
DO 1 |
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Channel |
Channel |
Channel |
Channel |
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4 |
3 |
2 |
1 |
8 Channel Digital Output Module
750-530
Bit 7 |
Bit 6 |
Bit 5 |
Bit 4 |
Bit 3 |
Bit 2 |
Bit 1 |
Bit 0 |
controls |
controls |
controls |
controls |
controls |
controls |
controls |
controls |
DO 8 |
DO 7 |
DO 6 |
DO 5 |
DO 4 |
DO 3 |
DO 2 |
DO 1 |
Channel |
Channel |
Channel |
Channel |
Channel |
Channel |
Channel |
Channel |
8 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
WAGO-I/O-SYSTEM 750 ETHERNET TCP/IP