Fieldbus Input (AI) and Output (AO) function blocks must have a valid XD-SCALE. When you configure fieldbus AI and AO function blocks, you must set valid XD-SCALE units or the block will remain in OOS. Only the AI function block XD-SCALE units can change the units in the transducer. XD_SCALE EU100 and EU0 do not have to match because only XD_SCALE units are transferred to the transducer block. Check proper scale and unit information using the transducer block properties for the specific transmitter. To find units for a device, refer to the information on valid units and channel values.