Abstract: In a method for testing functionality of a field device or a field device for sending a control signal to a final controlling device of an industrial processing plant, the final controlling device is operated by a secondary power. With the method, a current/secondary power converter is provided for generating a predetermined secondary power safety control signal to bring the final controlling device into a predetermined safe position. An electronic safety circuit is provided connected to the current/secondary power converter which, depending on an electrical control signal received by the field device, is switched from a passive state into an active state in which the electronic safety circuit causes the current/secondary power converter to output the secondary output power safety control signal. The safety circuit automatically adopts the active state if the electrical control signal falls below or exceeds at least one of a current and a voltage threshold value specific to the safety circuit.

Abstract: In a method for testing functionality of a field device or a field device for sending a control signal to a final controlling device of an industrial processing plant, the final controlling device is operated by a secondary power. With the method, a current/secondary power converter is provided for generating a predetermined secondary power safety control signal to bring the final controlling device into a predetermined safe position. An electronic safety circuit is provided connected to the current/secondary power converter which, depending on an electrical control signal received by the field device, is switched from a passive state into an active state in which the electronic safety circuit causes the current/secondary power converter to output the secondary output power safety control signal. The safety circuit automatically adopts the active state if the electrical control signal falls below or exceeds at least one of a current and a voltage threshold value specific to the safety circuit.