Safety circuit and method for testing a safety circuit in an automation system
AssigneeWAGO Verwaltungsgesellschaft mit beschraenkter Haftung
InventorsAlexander Buelow, Christian Voss, Torsten Meyer
Life of this patent
Estimating the term…
Abstract
A safety circuit for the multi-channel processing of an input signal. The safety circuit includes an analog-to-digital conversion device having a first analog input and a second analog input and at least one digital output for processing the input signal. Furthermore, the safety circuit has a test device which is set up to apply a test signal at the first and/or second input of the A/D conversion device in such a way that the test signal superposes the input signal such that the test signal dominates the input signal.
Claims17
A safety circuit, comprising:
- an input circuit adapted to input a first input signal and a second input signal and provide the first input signal and the second input signal at an output;
- an A/D converter having a first analog input and a second analog input and a digital output;
- a first signal line connected to the output of the input circuit and to the first analog input of the A/D converter to relay the first input signal, from the input circuit, in analog form, wherein the A/D converter device is configured to convert the first input signal in analog form at the first analog input to a first input signal in digital form and to output the first input signal in digital form at the digital output;
- a second signal line connected to the output of the input circuit and to the second analog input of the A/D converter to relay the second input signal, from the input circuit, in analog form, wherein the A/D converter is arranged to convert the second input signal in analog form at the second analog input to a second input signal in digital form and to output the second input signal in digital form at the digital output;
- a control and evaluation device for evaluating the first input signal in digital form and the second input signal in digital form, wherein the digital output of the A/D converter is connected to at least one input of the control and evaluation device;
- and
- a test device to output an analog test signal, wherein the test device has a control input which is connected to a control output of the control and evaluation device and wherein the control and evaluation device is further configured to control the test device,
- wherein the test device has a first analog test output to output the analog test signal, the first analog test output being connected to the first signal line and the test device has a second analog test output to output the analog test signal, the second analog test output being connected to the second signal line.
A method for testing a safety circuit, the method comprising:
- providing a signal source for generating an analog test signal;
- and
- outputting the analog test signal, from a test device to a first and/or a second signal line,
- connecting, during a test period, the analog test signal applied to a test input of the test device via a switching device,
- replacing the analog test signal with a first input signal in analog form at the first analog input of an A/D converter and/or replacing the analog test signal with a second input signal in analog form at the second analog input of the A/D converter.
Dependencies are inferred from the claim text.