Example methods and apparatus to bind properties in a process control system are disclosed. Pre-positioning the clamp piston can include leaving a positioning gap between portions of a mold before releasably locking a tie bar to one of the moving or stationary platens, and then advancing the moving platen to substantially close the positioning gap after the releasable locking has been completed. While a radio signal is transmitted from the transmitter of the currently used wireless communication apparatus, a reception limit signal is transmitted from the output portion of the currently used apparatus to the respective input portion of each of the nearby standby apparatuses so that the reception ability of the receiver of the standby apparatus is effectively limited.