| 摘要 |
<p>PURPOSE:To diagnose the working state of a relay selected out of a program by comparing the 1st time detected by a time detecting means with the 2nd time set by a time setting means. CONSTITUTION:A detecting circuit 3 supplies the OFF-ON rise signal corresponding to the working of the external relay contact to a counter 5 of a time detecting means 4 to reset the counter 5. A clock pulse is applied to the counter 5 and the counter 5 counts the time passed after the counter 5 is reset to give this counting result to the terminal at one side of a comparison means 7 as the 1st time Ta. A time setting means 8 contains a time setting switch 9 to set the time data in accordance with the prescribed working program of the external relay. This set time data is supplied to the other terminal of the means 7 as the 2nd time Tb. These times Ta and Tb are compared with each other by the means 7. Then the normal and abnormal actions of the relay are judged with Ta<Tb and Ta>=Tb respectively.</p> |
