Breakdown is diagnosed oneself is a system but the important facet that maintainability designs, it is the serious question that raises systematic dependability to must consider. Diagnose oneself basically use software method to judge breakdown part and reason.
Different control system differs from diagnostic content. PLC has diagnose ability very by force oneself, appear from die barrier or peripheral equipment breakdown when PLC, what the glow diode of some diagnostic directive functions provides on usable PC is bright, destroy will search.
One, power source breakdown is diagnosed
Power source light is not bright, need to undertake diagnostic to power supply system. If power source light is not bright, check above all whether to have report, if have report, criterion next with respect to voltage of check power source appropriate, improper adjust voltage, if power source voltage is appropriate, it is whether silk of check frit burns out next, if burn out,change power source of of frit silk check, if did not burn out, it is whether check wiring has next by accident, if wiring is not had by accident, should change power source component.
2, operational failure is diagnosed
Power supply is normal, moving indicator light is not bright, demonstrative system already was planted because of some unusual and it is normal to was stopped move.
Diagnosing an input / when outputting breakdown, optimal method is the problem that distinguishing is module oneself after all, still be the problem on spot join. If have power source indicator and logistic indicator, module breakdown discovers easily. Normally, it is to change first module, or measure an input or output terminal board measured value of two upright voltage is true, module is not answered, should change module. Be like after changing, still disable, may be spot join gives an issue. Output equipment ends, the voltage between output end achieves some to book a value, show the spot has even the line by accident. If output implement get drive, and LED indicator does not shine to should replace module. If cannot from Ⅰ / problem of of the in ○ module, should check module to receive plug-in unit to whether be contacted undesirable or did not aim. Finally, check receives plug-in unit terminal to have do not have a line, there is the solder that do not have empty to nod ED position indicator to be able to provide a lot of information about spot equipment, join and I/O module on module terminal. Major input / output module has an indicator at least. Input indicator of module standing power source, output module criterion standing a logistic indicator.
3, input breakdown is diagnosed
4, output breakdown is diagnosed
5, systematic breakdown and hardware breakdown are diagnosed
Usually, breakdown of PLC occurrence system, its indicate the lantern show to be shown somewhat reflect;
1, examine ERROR lamp to whether shine
2, examine SF to whether the lamp shines or shine
3, examine PROG to whether the lamp shines or shine
4, examine ALARM to whether the lamp shines or shine
5, machine stage is started, the input output indicator light that watchs module to go up has invariant
6, the examination of external environment
The environmental factor that affects PLC work basically has temperature, humidity, noise and dust, and corrosive soda acid.
