Mapping of the Fieldbus Box Modules

The Fieldbus Box Modules have a memory for the image of the process data. This memory can be read from or written to by the fieldbus master. The size and the type of the process data image depends on the type of Fieldbus Box, the configuration, the fieldbus system and the fieldbus master.

  • bit oriented Fieldbus Box Modules (basically digital modules) have a fixed quantity of data.
  • Only in the case of the byte oriented Fieldbus Box Modules (e.g. analog modules und modules for special functions) some changes can be made:
    - compact and complete mapping
    - swapping the high and low bytes  (Intel / Motorola format)
    - Word-Alignment (only LightBus and Ethernet)
  • A Coupler Box has a variable mapping that depends on the type and number of extension boxes that are connected.

Bit oriented Fieldbus Box Modules

Bit oriented Fieldbus Box Modules possess a specified number of inputs and/or outputs, that cannot be changed.

 

Input Data

Output Data

Module

Number of used bits

Number of used  bits

IP10xx-Byyy
IE10xx

8

0

IP20xx-Byyy
IE20xx

0

8

IP23xx-Byyy
IE23xx

4 (although the 4 most significant bit are not used, they occupy space in the process data memory)

4 (although the 4 most significant bit are not used, they occupy space in the process data memory)

IP2400-Byyy, IP2401-Byyy
IE2400, IE2401, IE2403

8

8

"yyy" stands for the bus system and the bus connection (see chapter Naming Conventions).

Byte oriented Fieldbus Boxes

Byte oriented Fieldbus Box Modules can operate with compact or complete process image. The number of bytes for complete mapping are given in brackets.

 

Input Data

Output Data

Module

Number of used bytes

Number of used bytes

IP15xx-Byyy
IE15xx

6 (6)

6 (6)

IP25xx-Byyy
IE25xx

6 (6)

6 (6)

IE2808

2 (3)

2 (3)

IP3xxx-Byyy
IE3xxx

8 (12)

0 (12)

IP41xx-Byyy
IE41xx

0 (12)

8 (12)

IP5009-Byyy
IE5009

4 (6)

4 (6)

IP5109-Byyy
IE5109

6 (8)

6 (8)

IE5209

10 (10)

10 (10)

IP6xxx-Byyy
IE6xxx

6 (6)

6 (6)

With activated Word-Alignment, the number of occupied bytes can increase because not used bytes may be added. Details can be taken from the module specific mapping descriptions.

Further Information