A power conversion device includes a function of improving safety of a system by making a dynamical setting for a safety function operation at a time of detecting an abnormality in a system operation or a diagnosis error in accordance with a condition of the system at a time of the abnormality. A power conversion system includes a power conversion device main body configured to drive a motor and a safety function unit configured to execute a safety function. The safety function unit outputs a safety function operation instruction signal when receiving a safety request signal, and the power conversion device main body controls the motor by the safety function operation instruction signal. The safety function unit monitors a state of the motor, and, in a case where the state of the motor exceeds a predetermined range, executes a threshold-value-excess post-process by a safety function operation selected in advance.

The purpose of the present invention is to provide, in a power conversion device which is ready for functional safety, a function of improving safety of a system by making a dynamical setting for a safety function operation at a time of detecting an abnormality in a system operation or a diagnosis error in accordance with a condition of the system at a time of the abnormality. To achieve the purpose described above, a power conversion system includes a power conversion device main body configured to drive a motor and a safety function unit configured to execute a safety function. The safety function unit outputs a safety function operation instruction signal when receiving a safety request signal, and the power conversion device main body controls the motor by the safety function operation instruction signal. The safety function unit monitors a state of the motor, and, in a case where the state of the motor exceeds a predetermined range, executes a threshold-value-excess post-process by a safety function operation selected in advance.

A robot control system includes an operation command output unit which outputs an operation command of a motor, a position detection unit which is provided on the motor to detect the position of a control shaft, a stop signal output unit which outputs a stop signal to stop the robot when the speed of the control shaft acquired from the position detection unit exceeds a speed threshold value, and an operation command interruption unit which interrupts the operation command outputted from the operation command output unit when the stop signal is outputted.

The operation state of a servo motor is monitored and output to a user before automatic termination of power to the motor. A servo system includes a servo motor and a safety unit. The safety unit cuts off electric power to the servo motor when at least one of a speed, a position, acceleration, an amount of movement, a movement direction, and torque of the servo motor is outside a first operation range. Furthermore, the safety unit outputs a warning when at least one of the speed, the position, the acceleration, the amount of movement, the movement direction, the torque is within the first operation range, but is outside a second operation range that is narrower than the first operation range. User controls allow reduced operation when outside the second operation range.