SFC-2501 manipulator is a unit of DDZ-S series instrument. It is usually completed with S-series instrument, KMM，KMS single circuit regulator and DTZB-2310A digital regulator. It can switch between automatic and manual. At the same time, it is used to indicate the valve position signal which send from on-site actuator and convert the signal to voltage signal then send to regulator. If the digital contact signal can be connected suitable with regulator, it will realize no disturbance when switch from manual to automatic. There are two completely same circuits.