Fieldbus Direct, Indirect and Indirect square root Functions

Ranging in Fieldbus transmitters is a somewhat confusing topic due to the unfortunate names given to the different L_Type parameter options.

Here is a list of the L_Type parameter options in FF devices along with their meanings:

Direct = the AI block will publish the signal output by the XD block, regardless of the specified OUT_Scale range

Indirect = the AI block will mathematically scale the signal from the XD block into a range specified by OUT Scale parameters using a linear equation (e.g. y = mx + b)

Indirect square root = same as above, except that a square-root function is applied to the percentage of range (useful when characterizing flow transmitters based on differential pressure measurement)

More info @