A method for transmitting a program and parameter to a programmable logic controller, PLC which method is for use in an adapter , the method comprising the steps of: the adapter establishing a connection with the PLC and a connection with a mobile terminal ; the adapter reading a state of the PLC from the PLC ; the adapter converting data on the state of the PLC into data that a dedicated application program on the mobile terminal is capable of recognizing and transmitting the data that the dedicated application program is capable of recognizing to the mobile terminal ; the adapter receiving a program and/or parameter that the mobile terminal has downloaded from a cloud server and that corresponds to the state of the PLC ; and the adapter converting the program and/or parameter into data that conforms to a communications protocol exclusive to the PLC and transmitting to the PLC the data that conforms to the communications protocol exclusive to the PLC , the establishing of the connection with the PLC by the adapter including: detecting whether a port and protocol have been set; in a case where the port and protocol have been set, establishing a wired connection with the PLC on a basis of the port and protocol set; and in a case where the port and protocol have not been set, selecting a protocol from a protocol list stored in advance, selecting a port from a port list stored in advance, selecting a port setting from a port setting list stored in advance, and establishing a wired connection with the PLC with use of the protocol selected, the port selected, and the port setting selected. the adapter establishing a connection with the PLC and a connection with a mobile terminal ; the adapter reading a state of the PLC from the PLC ; the adapter converting data on the state of the PLC into data that a dedicated application program on the mobile terminal is capable of recognizing and transmitting the data that the dedicated application program is capable of recognizing to the mobile terminal ; the adapter receiving a program and/or parameter that the mobile terminal has downloaded from a cloud server and that corresponds to the state of the PLC ; and the adapter converting the program and/or parameter into data that conforms to a communications protocol exclusive to the PLC and transmitting to the PLC the data that conforms to the communications protocol exclusive to the PLC , the establishing of the connection with the PLC by the adapter including: detecting whether a port and protocol have been set; in a case where the port and protocol have been set, establishing a wired connection with the PLC on a basis of the port and protocol set; and in a case where the port and protocol have not been set, selecting a protocol from a protocol list stored in advance, selecting a port from a port list stored in advance, selecting a port setting from a port setting list stored in advance, and establishing a wired connection with the PLC with use of the protocol selected, the port selected, and the port setting selected. detecting whether a port and protocol have been set; in a case where the port and protocol have been set, establishing a wired connection with the PLC on a basis of the port and protocol set; and in a case where the port and protocol have not been set, selecting a protocol from a protocol list stored in advance, selecting a port from a port list stored in advance, selecting a port setting from a port setting list stored in advance, and establishing a wired connection with the PLC with use of the protocol selected, the port selected, and the port setting selected. <EOS>