An input module for a programmable logic controller able to be connected to a plurality of elements of an automated chain, the input module comprising: - inputs (32A, 32B), each input (32A, 32B) being able to receive the signal from at least one element (14A, 14B) of the plurality of elements (12, 14A, 14B, 16, 18, 20A, 20B, 20C, 20D), - interfaces (40A, 40B), each interface (40A, 40B) being associated with a single input and comprising at least one output (40A6, 40B6) able to operate in three different states: ∘ a forcing state corresponding to the maximum voltage that the output (40A6, 40B6) of the interface (40A, 40B) is able to deliver, ∘ a low state corresponding to the minimum voltage that the output (40A6, 40B6) of the interface (40A, 40B) is able to deliver, and ∘ a read state in which the output (40A6, 40B6) of the interface (40A, 40B) is able to deliver an image of the signal received by the input (32A, 32B) associated with the considered interface (40A, 40B), - a test block connected to each of the interfaces (40A, 40B) and able to impose the state of the output (40A6, 40B6) of each interface (40A, 40B), and - a processing sub-module able to compare the state of the output (40A6, 40B6) of each interface (40A, 40B) with the state imposed by the test block and to deduce an operating anomaly of the input module (32, 34) therefrom when the state of the output (40A6, 40B6) of at least one interface (40A, 40B) differs from the state imposed by the test block. - inputs (32A, 32B), each input (32A, 32B) being able to receive the signal from at least one element (14A, 14B) of the plurality of elements (12, 14A, 14B, 16, 18, 20A, 20B, 20C, 20D), - interfaces (40A, 40B), each interface (40A, 40B) being associated with a single input and comprising at least one output (40A6, 40B6) able to operate in three different states: ∘ a forcing state corresponding to the maximum voltage that the output (40A6, 40B6) of the interface (40A, 40B) is able to deliver, ∘ a low state corresponding to the minimum voltage that the output (40A6, 40B6) of the interface (40A, 40B) is able to deliver, and ∘ a read state in which the output (40A6, 40B6) of the interface (40A, 40B) is able to deliver an image of the signal received by the input (32A, 32B) associated with the considered interface (40A, 40B), ∘ a forcing state corresponding to the maximum voltage that the output (40A6, 40B6) of the interface (40A, 40B) is able to deliver, ∘ a low state corresponding to the minimum voltage that the output (40A6, 40B6) of the interface (40A, 40B) is able to deliver, and ∘ a read state in which the output (40A6, 40B6) of the interface (40A, 40B) is able to deliver an image of the signal received by the input (32A, 32B) associated with the considered interface (40A, 40B), - a test block connected to each of the interfaces (40A, 40B) and able to impose the state of the output (40A6, 40B6) of each interface (40A, 40B), and - a processing sub-module able to compare the state of the output (40A6, 40B6) of each interface (40A, 40B) with the state imposed by the test block and to deduce an operating anomaly of the input module (32, 34) therefrom when the state of the output (40A6, 40B6) of at least one interface (40A, 40B) differs from the state imposed by the test block.