Methods and apparatuses for monitoring the functionality of redundantly interconnected contacts
For providing a very simple and reliable monitoring of the functionality of contacts together with a high flexibility of selection of the contacts a method for monitoring the functionality of redundantly interconnected contacts is provided, preferably within a load current circuit, wherein said n contacts, n=2, provide an electrical connection between a power supply and a load, wherein said n contacts are switchable by a controller and wherein each of said n contacts is designed for providing the electrical connection between the power supply and the load all alone. The method is characterized in that the controller switches on said n contacts during n subsequent activations according to a defined schedule according to which at the first of said n subsequent activations one of said n contacts is switched on first and the remaining n−1 contacts are switched on afterwards, so that a verification regarding the functionality of said one of said n contacts is possible, and according to which at each of the n−1 remaining subsequent activations a further one of said n contacts is switched on first with switching on of the remaining n−1 contacts afterwards, so that after said n subsequent activations each of said n contacts has once been switched on first and a verification regarding the functionality of each of said n contacts is possible. Further, a corresponding method for subsequent deactivations and corresponding apparatuses are provided.
1. Method for monitoring the functionality of n contacts, wherein said n contacts comprise at least three redundantly interconnected contacts that each provide an electrical connection between a power supply and a load, wherein said n contacts are switchable by a controller and wherein each of said n contacts is designed for providing the electrical connection between the power supply and the load all alone, wherein the method comprises the steps of:
switching on, via the controller, said n contacts during n subsequent activations according to a defined schedule according to which at the first of said n subsequent activations only one of said n contacts is switched on first and the remaining n−1 contacts are collectively switched on afterwards, so that a verification regarding the functionality of said one of said n contacts is possible, and
at each of the n−1 remaining subsequent activations, switching on first, via the controller, only a further one of said n contacts with collective switching on of all the remaining n−1 contacts afterwards, so that after said n subsequent activations each of said n contacts has once been switched on alone and first for an independent verification regarding the functionality of each of said n contacts.
2. Method for monitoring the functionality of n contacts, wherein said n contacts comprise at least three redundantly interconnected contacts that each provide an electrical connection between a power supply and a load, wherein said n contacts are switchable by a controller and wherein each of said n contacts is designed for providing the electrical connection between the power supply and the load all alone, wherein the controller switches off said n contacts during n subsequent deactivations according to a defined schedule according to which at the first of said n subsequent deactivations n−1 of said n contacts are collectively switched off first and the only remaining contact is switched off afterwards, so that a verification regarding the functionality of said only remaining contact is possible, and according to which at each of the n−1 remaining subsequent deactivations a further one of said n contacts is switched off afterwards with collective switching off of the remaining n−1 contacts before, so that after said n subsequent deactivations each of said n contacts has once been switched off alone and after the remaining n−1 contacts for an independent verification regarding the functionality of each of said n contacts.
3. Method according to claim 1 , wherein the verification comprises checking whether the contact provides a reliable switching on process regarding the electrical connection.
4. Method according to claim 1 , wherein the verification comprises checking whether the electrical connection is already activated after switching on the one of said n contacts or not until after switching on the remaining n−1 contacts.
5. Method according to claim 1 , wherein the verification comprises checking whether the contact provides a reliable switching off process regarding the electrical connection.
6. Method according to claim 1 , wherein the verification comprises checking whether the electrical connection is already deactivated after switching off the n−1 contacts of said n contacts or not until after switching off the remaining contact.
7. Method according to claim 1 , wherein depending on the result of the verification a control signal, an indication or an activity is provided.
8. Method according to claim 7 , wherein the control signal, the indication or the activity is provided immediately after a detection of a malfunction or failure of a contact.
9. Method according to claim 7 , wherein the control signal, the indication or the activity is provided after said n subsequent activations or deactivations, if a malfunction or failure of a contact is detected by the verification.
10. Method according to claim 7 , wherein the control signal is an optical, acoustical or electronic control signal.
11. Method according to claim 1 , wherein the contacts are relay contacts.
12. Method according to claim 1 , wherein the controller is a programmable logic controller.
13. Method according to claim 1 , wherein the power supply and load are electrically or galvanically isolated from the controller.
14. Apparatus comprising a controller configured for performing the method according to claim 1 .
15. Apparatus comprising a controller configured for performing the method according to claim 2 .
16. Method according to claim 1 , wherein the method is conducted within a load current circuit.
17. Method according to claim 2 , wherein the method is conducted within a load current circuit.