Evaluation system, safety controller, computer readable storage medium, and evaluation method

A safety controller that evaluates functional safety for a safety program in order to cause an output device to operate such that safety is maintained if a predetermined condition is satisfied, the safety controller comprising:

• a processing execution means for deciding a value of an output signal to be output to one or more corresponding output devices by executing computation in accordance with the safety program, on the basis of an input signal from any of one or more input devices;
• a setting means for receiving an evaluation condition that includes an input signal of an evaluation target and an expected output value as a value of an output signal to be output to an output device corresponding to a change in a value of the input signal;
• a first determination means for determining whether or not a first output value of an output signal decided by the processing execution means coincides with the expected output value on the basis of reception of a change in the value of the input signal of the evaluation target from a first input value as an initial value to a second input value from an input device of the evaluation target;
• a second determination means for determining whether or not a second output value of an output signal decided by the processing execution means coincides with the first output value on the basis of reception of returning of the value of the input signal of the evaluation target from the second input value to the first input value from the input device of the evaluation target;
• and
• an output means for outputting determination results of the first determination means and the second determination means in association with the input signal of the evaluation target.

A non-transitory computer readable storage medium that evaluates functional safety for a safety program in order to cause an output device to operate such that safety is maintained if a predetermined condition is satisfied, the non-transitory computer readable storage medium storing a plurality of program instructions, wherein the program instructions are loaded into a computer to execute steps of:

• deciding a value of an output signal to be output to one or more corresponding output devices by executing computation in accordance with the safety program, on the basis of an input signal from any of one or more input devices;
• receiving an evaluation condition that includes an input signal of an evaluation target and an expected output value as a value of an output signal to be output to an output device corresponding to a change in a value of the input signal;
• determining whether or not a first output value of an output signal decided by computation in accordance with the safety program coincides with the expected output value on the basis of reception of a change in the value of the input signal of the evaluation target from a first input value as an initial value to a second input value from an input device of the evaluation target;
• determining whether or not a second output value of an output signal decided by the computation in accordance with the safety program coincides with the first output value on the basis of reception of returning of the value of the input signal of the evaluation target from the second input value to the first input value from the input device of the evaluation target;
• and
• outputting determination results in the determining step in association with the input signal of the evaluation target.

An evaluation method that evaluates functional safety for a safety program in order to cause an output device to operate such that safety is maintained if a predetermined condition is satisfied, the evaluation method comprising steps of:

• deciding a value of an output signal to be output to one or more corresponding output devices by executing computation in accordance with the safety program, on the basis of an input signal from any of one or more input devices;
• receiving an evaluation condition that includes an input signal of an evaluation target and an expected output value as a value of an output signal to be output to an output device corresponding to a change in a value of the input signal;
• determining whether or not a first output value of an output signal decided by computation in accordance with the safety program coincides with the expected output value on the basis of reception of a change in the value of the input signal of the evaluation target from a first input value as an initial value to a second input value from an input device of the evaluation target;
• determining whether or not a second output value of an output signal decided by the computation in accordance with the safety program coincides with the first output value on the basis of reception of returning of the value of the input signal of the evaluation target from the second input value to the first input value from the input device of the evaluation target;
• and
• outputting determination results in the determining step in association with the input signal of the evaluation target.