Module for a programmable controller, - wherein the module has a plurality of analogue input channels (4a to 4d) each for an analogue input signal (Ea to Ed), - wherein the module has a control and evaluation device and for each input channel (4a to 4d) - in each case independently of the other input channels (4a to 4d) - input terminals (9a, 9d) for supplying the respective analogue input signal (Ea to Ed), characterised in that - the module has for each input channel (4a to 4d) - in each case independently of the other input channels (4a to 4d) - a first and a second analogue-to-digital converter (10, 11), a first, a second, a third and a fourth coupling element (12 to 15) and a switchover device, - the control and evaluation device has for each input channel (4a to 4d) - in each case independently of the other input channels (4a to 4d) - an evaluation circuit, a test signal generator and a switching signal generator, - an input side of the respective first analogue-to-digital converter is connected directly or indirectly with the respective input terminals (9a to 9d) and an output side of the respective first analogue-to-digital converter is connected via the respective first coupling element with the respective evaluation circuit, - the respective switchover device has a first and a second signal input (22, 23), a signal output and a control input, - the first signal input of the respective switchover device is connected directly or indirectly with the respective input terminals (9a to 9d), the second signal input of the respective switchover device is connected via the respective third coupling element with the respective test signal generator, the control input of the respective switchover device is connected via the respective fourth coupling element with the respective switching signal generator and the signal output of the respective switchover device is connected with an input side of the respective second analogue-to-digital converter, - an output side of the respective second analogue-to-digital converter is connected via the respective second coupling element with the respective evaluation circuit and - the respective first, the respective second, the respective third and the respective fourth coupling elements (12 to 15) are each embodied as a coupling element which brings about electrical isolation. - wherein the module has a plurality of analogue input channels (4a to 4d) each for an analogue input signal (Ea to Ed), - wherein the module has a control and evaluation device and for each input channel (4a to 4d) - in each case independently of the other input channels (4a to 4d) - input terminals (9a, 9d) for supplying the respective analogue input signal (Ea to Ed), - the module has for each input channel (4a to 4d) - in each case independently of the other input channels (4a to 4d) - a first and a second analogue-to-digital converter (10, 11), a first, a second, a third and a fourth coupling element (12 to 15) and a switchover device, - the control and evaluation device has for each input channel (4a to 4d) - in each case independently of the other input channels (4a to 4d) - an evaluation circuit, a test signal generator and a switching signal generator, - an input side of the respective first analogue-to-digital converter is connected directly or indirectly with the respective input terminals (9a to 9d) and an output side of the respective first analogue-to-digital converter is connected via the respective first coupling element with the respective evaluation circuit, - the respective switchover device has a first and a second signal input (22, 23), a signal output and a control input, - the first signal input of the respective switchover device is connected directly or indirectly with the respective input terminals (9a to 9d), the second signal input of the respective switchover device is connected via the respective third coupling element with the respective test signal generator, the control input of the respective switchover device is connected via the respective fourth coupling element with the respective switching signal generator and the signal output of the respective switchover device is connected with an input side of the respective second analogue-to-digital converter, - an output side of the respective second analogue-to-digital converter is connected via the respective second coupling element with the respective evaluation circuit and - the respective first, the respective second, the respective third and the respective fourth coupling elements (12 to 15) are each embodied as a coupling element which brings about electrical isolation.