A system comprising a robot and a multiplex device , wherein the robot is configured to perform work based on operation of a movable section and transmit data related to the work using the multiplex device, the multiplex device comprising: a multiplex connecting section connected to a movable side multiplex device , the multiplex connecting section being configured to transmit a position signal (LSD1) outputted from a position signal output section connected to the movable side multiplex device by multiplexing communication with the movable side multiplex device ; an amplifier connecting section connected to a position signal output section amplifier , the amplifier connecting section being configured to transmit the position signal (LSD1) to the position signal output section amplifier , characterized by a measuring device connecting section connected to a position signal measuring device , and a switching section configured to switch from a connection between the multiplex connecting section and the position signal output section amplifier , and a connection between the multiplex connecting section and the position signal measuring device in accordance with detection of a connection between the measuring device connecting section and the position signal measuring device . wherein the robot is configured to perform work based on operation of a movable section and transmit data related to the work using the multiplex device, the multiplex device comprising: a multiplex connecting section connected to a movable side multiplex device , the multiplex connecting section being configured to transmit a position signal (LSD1) outputted from a position signal output section connected to the movable side multiplex device by multiplexing communication with the movable side multiplex device ; an amplifier connecting section connected to a position signal output section amplifier , the amplifier connecting section being configured to transmit the position signal (LSD1) to the position signal output section amplifier , characterized by a measuring device connecting section connected to a position signal measuring device , and a switching section configured to switch from a connection between the multiplex connecting section and the position signal output section amplifier , and a connection between the multiplex connecting section and the position signal measuring device in accordance with detection of a connection between the measuring device connecting section and the position signal measuring device . a multiplex connecting section connected to a movable side multiplex device , the multiplex connecting section being configured to transmit a position signal (LSD1) outputted from a position signal output section connected to the movable side multiplex device by multiplexing communication with the movable side multiplex device ; an amplifier connecting section connected to a position signal output section amplifier , the amplifier connecting section being configured to transmit the position signal (LSD1) to the position signal output section amplifier , characterized by a measuring device connecting section connected to a position signal measuring device , and a switching section configured to switch from a connection between the multiplex connecting section and the position signal output section amplifier , and a connection between the multiplex connecting section and the position signal measuring device in accordance with detection of a connection between the measuring device connecting section and the position signal measuring device . <EOS>