| 摘要 |
PURPOSE:To shorten inspecting time by detecting abnormality in an input circuit based on the difference between the input to be obtained upon application of inspecting current and the input to be obtained upon release of the inspecting current. CONSTITUTION:Upon provision of an analog input inspection command, an output is produced from an AND gate 22 based on a first step command then the output IL from a system current/voltage input converter 20 is added to the output IT from an inspection current oscillator 23 and subjected to A/D conversion through an A/D converter 28 and a filter 25, thereafter it is stored in a memory 29. Output from the AND gate 22 is blocked based on a second step command, then only the output IL' from the input converter 20 is subjected to A/D conversion and fed to an input circuit 30. A difference comparison circuit 31 judges abnormality at the input section based on the difference between the outputs from the memory circuit 29 and the input circuit 30. |
