Example implementations include a method of pre-bootup fault monitor of a LASER diode driver output, by applying a first power to a pre-bootup fault monitor device, setting a fault condition at the pre-bootup fault monitor device to a no-fault state, initiating the pre-bootup fault monitor device, determining whether a first impedance of driver output satisfies an impedance threshold, and in response to a determination that the first impedance satisfies the impedance threshold, applying a second power to the output device. Example implementations also include a system with a LASER output device, and a pre-bootup fault monitor device operatively coupled to the LASER output device, and operable to activate in response to receiving a first power, set a fault condition to a no-fault state, determine whether a first impedance of the output driver satisfies an impedance threshold, and, in response to a determination that the first impedance satisfies the impedance threshold, apply a second power to the LASER output device, and a power-on reset controller operatively coupled to the pre-bootup fault monitor and operable to, in response to the determination that the first impedance satisfies the impedance threshold, deactivate the pre-bootup fault monitor.

Example implementations include a method of pre-bootup fault monitor of a LASER diode driver output, by applying a first power to a pre-bootup fault monitor device, setting a fault condition at the pre-bootup fault monitor device to a no-fault state, initiating the pre-bootup fault monitor device, determining whether a first impedance of driver output satisfies an impedance threshold, and in response to a determination that the first impedance satisfies the impedance threshold, applying a second power to the output device. Example implementations also include a system with a LASER output device, and a pre-bootup fault monitor device operatively coupled to the LASER output device, and operable to activate in response to receiving a first power, set a fault condition to a no-fault state, determine whether a first impedance of the output driver satisfies an impedance threshold, and, in response to a determination that the first impedance satisfies the impedance threshold, apply a second power to the LASER output device, and a power-on reset controller operatively coupled to the pre-bootup fault monitor and operable to, in response to the determination that the first impedance satisfies the impedance threshold, deactivate the pre-bootup fault monitor.

A programmable logic controller configured to include a control unit and a power supply unit equipped with a limited-life component. The power supply unit includes a remaining life storage unit to store remaining life information indicating the remaining life of the power supply unit. The control unit includes a load current calculation unit to calculate the load current flowing in the programmable logic controller; an estimated temperature calculation unit to calculate, on the basis of the ambient temperature information obtained from the user and the load current, an estimated value of temperature of the limited-life component when the programmable logic controller is in operation; and a remaining life calculation unit to update the remaining life information on the basis of the operating time of the programmable logic controller and the estimated value.