Abstract: An electrical power supply system for a programmable logic controller, including: a first electrical power supply module configured to operate in a master mode to deliver at least one electrical supply voltage to the programmable logic controller; a second electrical power supply module configured to operate in a slave mode to deliver the electrical supply voltage to the programmable logic controller in event of failure of the first electrical power supply module; a control module configured to temporarily control switching of the first electrical power supply module to the slave mode and switching of the second electrical power supply module to the master mode; and a test module configured to test the second electrical power supply module when the second electrical power supply module is switched to the master mode.

Abstract: A method for determining a mean time to failure of an electrical device, and a method for adjusting a predetermined mean time to failure of an electrical power supply and for evaluating the adjusted mean time to failure. The method determines the mean time to failure by taking into account both operating conditions and operational load.

Abstract: A relay circuit and a method for performing a self-test. The relay circuit has four relays, each relay having a first forcibly guided contact and a second forcibly guided contact. The four relays are arranged in a first and a second pair of two in series connected first forcibly guided contacts. The first and second relay pair are arranged in parallel between a power supply connection and a load connection for switching a power supply to a load through the first forcibly guided contacts. Such a relay circuit enables supplying power via one of the relay pairs, while cutting power via the other relay pair, which facilitates testing of the relay pair which has cut power without interrupting the process supervised by the Safety Instrumented System which the relay circuit forms part of.

Abstract: A method for determining a mean time to failure of an electrical device, and a method for adjusting a predetermined mean time to failure of an electrical power supply and for evaluating the adjusted mean time to failure. The method determines the mean time to failure by taking into account both operating conditions and operational load.

Abstract: An electrical power supply system for a programmable logic controller, including: a first electrical power supply module configured to operate in a master mode to deliver at least one electrical supply voltage to the programmable logic controller; a second electrical power supply module configured to operate in a slave mode to deliver the electrical supply voltage to the programmable logic controller in event of failure of the first electrical power supply module; a control module configured to temporarily control switching of the first electrical power supply module to the slave mode and switching of the second electrical power supply module to the master mode; and a test module configured to test the second electrical power supply module when the second electrical power supply module is switched to the master mode.

Abstract: A relay circuit and a method for performing a self-test. The relay circuit has four relays, each relay having a first forcibly guided contact and a second forcibly guided contact. The four relays are arranged in a first and a second pair of two in series connected first forcibly guided contacts. The first and second relay pair are arranged in parallel between a power supply connection and a load connection for switching a power supply to a load through the first forcibly guided contacts. Such a relay circuit enables supplying power via one of the relay pairs, while cutting power via the other relay pair, which facilitates testing of the relay pair which has cut power without interrupting the process supervised by the Safety Instrumented System which the relay circuit forms part of.

Abstract: A module with isolated analog inputs for a programmable controller, the module including plural input pathways that are each isolated with aid of at least one optical isolation static relay controlled selectively with the aid of a controller. The module further includes a multiplexer including plural channels each controlled to open or to close, a channel of the multiplexer being placed in series with an isolated input pathway of the module.

Abstract: An electric control and protection system for an output channel of automation equipment, the output channel being capable of controlling an electrical load as a function of a control signal from the automation equipment, the control and protection system including: a device that switches the electrical load including an MOS switching transistor, a source of the MOS switching transistor being connected to a positive voltage terminal via a resistor and a drain of the MOS switching transistor being connected to the electrical load, the MOS switching transistor being switchable between an on-state in which the electrical load is connected to the resistor and an off-state.

Abstract: The present invention relates to a module with isolated analogue inputs for programmable controller, the said module comprising several input pathways that are each isolated with the aid of at least one optical isolation static relay (1a-4b) controlled selectively with the aid of control means (6), the said module being characterized in that it comprises a multiplexer (5) furnished with several channels (5a-5h) each controlled to open or to close, a channel of the multiplexer (5) being placed in series with an isolated input pathway (1-4) of the module.

Abstract: The invention relates to an electronic control and protection system for an output channel of automation equipment. It comprises: i) a device for switching (10) an electrical load (C) comprising an MOS switching transistor (T5), the source of which is connected to a positive voltage terminal (P) via a resistor (R5) and the drain of which is connected to the load (C), the transistor (T5) being switchable between an on-state in which the load (C) is connected to said resistor (R5) and an off-state; ii) a limiting device (20) limiting the voltage at the terminals of said resistor (R5) to a predetermined maximum value (VR5max); iii) an output channel cut-off device (30) able to switch the transistor (T5) to the off-state when the current flowing through said resistor (R5) passes a predetermined threshold for a predetermined duration.