Fieldbus coupler/controller |
• 45 |
Fieldbus controller 750-819 |
|
|
|
3.2.6.2 Addressing
The data of I/O modules, PFC-variables and CPs are absolute adressed for processing internally in the controller through an IEC 61131-3 program. This application program for the PLC functionality (CPU) of the PFC is created with WAGO-I/O-PRO 32 in accordance with IEC 61131-3.
The direct display of individual memory cells (absolute addresses) in accordance with IEC 61131-3 is made using special character strings in accordance with the following table:
Position |
Character |
Nomination |
Comment |
1 |
% |
Apply an absolute address |
|
2 |
I |
Input |
|
|
Q |
Output |
|
|
M |
Flag |
|
3 |
X* |
Single bit |
Data width |
|
B |
Byte (8 Bits) |
|
|
W |
Word (16 Bits) |
|
|
D |
Double word (32 Bits) |
|
4 |
|
Address |
|
|
|
|
|
* The character 'X' for single bits can be deleted.
Tab. 3-2: Absolute addresses
Attention
Enter the absolute address character strings without blanks!
Fig. 3-6: Examples for absolute addresses |
g912203e |
Modular I/O System
LONWORKS®
46 • Fieldbus coupler/controller Fieldbus controller 750-819
Note
For the number of input and output bits or bytes of the individual I/O modules please refer to the corresponding I/O module description.
The data width of the PFC variables depends on the according data type.
3.2.6.2.1 Addressing the I/O modules
Upon switching on the supply voltage, the data of the I/O modules are mapped into the process image.
The PFC functions simular to that of a PLC’s CPU enable the bus modules data and PFC variables to be processed within the IEC 61131-3 environment as internal applications, such as linking DIs with DOs. With absolute addresses, the CPU directly accesses the bus module data in the respective memory range (word 0 to 255).
Following this, the linking results can be directly written in the output data via absolute addressing.
Inputs |
Outputs |
I/O modules |
750-4xx....6xx |
%IW0 |
%QW0 |
PII |
PIO |
%IW255 |
%QW255 |
Inputs |
Outputs |
PLC functionality (CPU)
PII = Process Input
Image
PIO = Process Output
Image
Programmable Fieldbus Controller
Fig. 3-7: Data exchange between PLC functionality (CPU) of the PFC and I/O modulesg012943d
Note
A process image restructuring may result if a node is changed or extended. In this case the process data addresses also change in comparison with earlier ones. In the event of adding a module, take the process data of all previous modules into account.
Modular I/O System
LONWORKS®