| 摘要 |
<p>PURPOSE:To warn an external output part of the occurrence of abnormality by outputting an output abnormality detection signal after deciding the occurrence of abnormality of an external output part when the discordance is detected between the OFF command value supplied to a load and the current conversion value obtained in an output state of the load side. CONSTITUTION:An OFF relay number arithmetic part 14 operates the number of relays kept OFF based on the input current value and supplies this operated result to a comparison/decision part 16. At the same time, an ON/OFF command value arithmetic part 13 always operates the ON/OFF command values outputted from the ON/OFF command output parts 11 and 12 and supplies these operated results to the part 16. The part 16 compares the bit value of an OFF command with the operated number of OFF relays. If no coincidence is obtained from the comparison, it is decided that the abnormality occurred at the final output stage of an external output part 5 (6). Then an output abnormality detection signal is outputted to a warning output part 7 via an output abnormality detection signal output part 17. Thus it is possible to quickly detect such an abnormal state where the output cannot be turned off owing to the trouble of the external output part.</p> |
