# Fieldbus Configuration Parameters

An item is placed into the Fieldbus Map by defining the position of the least significant bit. This position is identified by a byte number and a bit number.

Item position
Information | Description
--- | ---
Starting byte | The byte number in which the least significant byte of the item is located. A numeric number in the range from zero to size minus one. The numbering starts from zero (0). The least significant byte or bit is number 0.
Starting bit | The bit number in which the least significant bit of the item is located. Starting from the previous selected starting byte. A numeric number in the range from zero to seven. The numbering starts from zero (0). The least significant byte or bit is number 0.
Length | A numeric value representing the number of bits in the item.
Range | Information only. Provides information of minimum length, the maximum length and the default length of the selected item.
Converter | A drop-down list of available signal converters. This is used if the SoftPLC has any requirements on how items are represented in a digital format.

The item converters are used to convert items between different data types.

Item converters
Information | Description
--- | ---
Boolean inversion | Inverts the digital signal from active high (1) to active low (0).
Fixed-point |