Hoist communication device in rail car of automated material handling system

A hoist communication device in a rail car of an automated material handling system, in which a master communication device connected to a rail car controller and a slave communication device connected to a gripper-unit are connected through a belt to operate the gripper-unit in accordance with a control signal of the rail car controller, thereby performing a hoist work, the hoist communication device comprising:

• the master communication device that allocates different carrier frequencies for each gripper device identification information to be modulated, when a control signal including the gripper device identification information corresponding to a destination is received from the rail car controller, superimposes at least one modulated control signal on a power supply line, and transmits the modulated control signal to the slave communication unit through the power supply line formed in the belt;
• and
• a slave communication device that supplies the power provided from the master communication unit to the gripper-unit having a plurality of gripper devices for performing the hoisting work, demodulates the modulated control signal using the corresponding carrier frequency, transmit the demodulated control signal to each gripper device corresponding to the corresponding identification information, modulates sensor signals applied from each gripper device by allocating different carrier frequencies, and transmits the sensor signals to the master communication unit through the power supply line formed in the belt.