66 • Fieldbus Controller 750-841

Data Exchange

3.1.5.2 Addressing

3.1.5.2.1 Addressing the I/O Modules

The arrangement of the I/O modules in a node is flexible and up to the user. Although, the user must verify that the power jumper contacts from one I/O module to the next are compatible and at the same voltage level.

When the controller addresses I/O modules, data of complex modules (modules occupying 1 or more bytes) are mapped first. They are mapped in the order of their physical position after the controller. As such, they occupy the addresses beginning with word 0. Following this, the digital modules are grouped in the form of words (16 bits per word). They are also arranged by their physical order. When the number of digital I/O’s exceeds 16 bits, the controller automatically starts another word.

Note

For detailed information on the number of input and output bits/bytes of a specific module, please refer to the modules manual.

Note

Changing the physical layout of a node will result in a new structure of the process image. Also, the addresses of the process data will change. When adding or removing modules, the process data must be verified.

Table 3.1: I/O Module Data Width

3.1.5.2.2 Address Range

Partition of Address ranges for the word-wise addressing acc. to IEC 61131-3 :

WAGO-I/O-SYSTEM 750 ETHERNET TCP/IP

68 • Fieldbus Controller 750-841

Data Exchange

Overview of the IEC 61131-3 address ranges:

Table 3.7: Overview IEC 61131-3 Address ranges

3.1.5.2.3 Absolute Addresses

Accessing individual memory cells (absolute addresses) in accordance with IEC 61131-3 is made using special character defined in the table below:

e. g. word wise: %QW27 (28. Word), bit wise: %IX1.9 (10. Bit in Word 2)

* The character ‘X’ for bits can be deleted

Table 3.8: Absolute Addresses

Note

Enter the absolute address character strings without blanks (white spaces)!

WAGO-I/O-SYSTEM 750 ETHERNET TCP/IP