Yokogawa Foundation Fieldbus Communication Module ALF111-S50/F9S00 Model ALF111 Foundation fieldbus Communication Module (for N-IO/FIO) is to establish communication between field control stations (FCS) and fieldbus devices compliant to the Foundation fieldbus (H1) such as transmitters and valve positioners. This Foundation fieldbus communication module can be mounted on the field control units (AFV30S/AFV30D, AFV40S/AFV40D, A2FV50S/A2FV50D, and A2FV70S/A2FV70D), ESB bus node unit (ANB10S/ANB10D) and optical ESB bus node unit (ANB11S/ANB11D).