Abstract: A ladder program unauthorized-use prevention system includes an engineering tool to decode a ladder program encrypted using a vendor private key, using a vendor public key paired with the vendor private key, and to encrypt the decoded ladder program using a controller public key such that the ladder program is operable on a specific programmable controller but is inoperable on other programmable controllers, and a programmable controller to decode the ladder program encrypted using the controller public key, using a controller private key paired with the controller public key, and to execute the ladder program decoded using the controller private key.

Abstract: A photovoltaic inverter that can respond to changes in temperature and the amount of sunlight and that can automatically start up is provided, which has a simple configuration and is inexpensive. The photovoltaic inverter has a first voltage detection means for detecting an output voltage of a photovoltaic panel; a current detection means, a control means and a driving means. It further has a model voltage storage means for storing a model voltage table of inverter start-up kick voltages produced based on variation values of an amount of sunlight, a model voltage read-out means, a second voltage detection means for detecting an inverter start-up kick voltage, and an inverter start-up control means.

Abstract: A control apparatus performs transmission and reception of data among a plurality of units mounted on a backplane. The control apparatus includes a communication unit that is mounted on the backplane and connected to the units via one-to-one communication lines and relays data among the units by using the communication lines.

Abstract: A method for artificially generating the output characteristic of a solar photovoltaic power generation module, and a solar photovoltaic power generation simulator power-supply apparatus having that output characteristic with the internal power loss reduced. The solar photovoltaic power generation simulator power-supply apparatus includes an IV storing means for storing, as IV curves, the voltage/current characteristics of solar photovoltaic power generations; an IV reading means; and means for generating an IV characteristic as an output target value of automatic control. The solar photovoltaic power generation simulator power-supply apparatus reads a designated particular IV curve from among the stored IV curves to generate a control signal for holding V associated with I on this curve, and supplies this control signal to a semiconductor switching element, which controls the power, thereby artificially generating a solar photovoltaic power generation output characteristic.