| 摘要 |
PURPOSE:To execute self-diagnosis of an output device, by detecting whether an output pulse corresponding to a data set from a computer is supplied exactly to an output side or not, by taking coincidence of a feedback pulse obtained through a photocoupler, and an input counting pulse. CONSTITUTION:When a data 1 is inputted to a presettable counter 4 together with a setting signal 2 from a computer, a clock pulse from an oscillator 17 is inputted to the counter 4 through a gate 7 which becomes on by an output of FFs 6, 6 set by the setting signal, and down-counting is executed. At the same time, the clock pulse drives a transistor 16 and becomes an output pulse 19 to a process side. On-and-off operations of this output pulse 19 are detected by a photocoupler 15, it is inputted to an EOR circuit 9 together with the clock pulse, and when dissidence of both of them is detected, it is inputted to a D-type FF12 and is set, and by its Q output, a light emitting diode 14 for an alarm is made to emit light, and also an abnormality signal 3 is outputted to the computer. |
