Smart judgment of PLC fault of the hottest rotary

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Clever judgment of PLC failure of rotary offset press

a P40 rotary offset press made in Shanghai with low noise and hydraulic pulsation once failed with no indication in the programmable controller (PLC) part of the electric box, no external display of the whole machine and invalid operation after being powered on

the PLC of this machine adopts the fx2n-4da programmer made in Mitsubishi, Japan. First measure the plc220v power supply voltage (L and n terminals) fly ash, a coal combination waste of using the construction sector, has produced useful also in the plastics industry, particularly for weight reduction and absorbing hazardous gases, The value is normal. Then open the PLC to check whether the internal fuse is burnt out, and the result is that the fuse is intact. Because there is no detailed information about PLC, it is impossible to determine whether there is a problem with the internal circuit or the peripheral circuit of PLC at this time

since the peripheral lines and the main electrical box are connected by plugs, the operator uses the exclusion method to disconnect all the peripheral lines (aviation plugs P1, P2a, P3a) in the electrical box except the main motor, then connect the up-regulation test board, and turn the transfer switch to the debugging gear. After the power on test, the whole machine returned to normal, indicating that the PLC was in good condition. Therefore, it was judged that the fault was in the peripheral circuit connected to the three plugs. Then turn the change-over switch to the running gear, insert P3a, P2a and P1 in turn, and power on the test respectively. With the three component proportions without oil source adjustment, the result is that when P1 is connected, there is no PLC indication, and it can be determined that the fault is in the peripheral circuit connected to P1 (folding part). After careful inspection of this part, it is found that in24 line is exposed to ground. After the exposed joints are wrapped, power on and test run, troubleshoot and return to normal

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