Detection of paper breaking fault of rotary machine
a Gauss rotary printing machine (wd-a) made in Shanghai of our factory broke paper when the paper cutter did not act during use, resulting in the paper winding on the drum and crushing the blanket
another Gauss printing machine (WS-A) in our factory once had such a situation: large shipping enterprises were encouraged to enter Hainan. Because the water content of compressed air was too large and there were too many dirty things, the friction between the valve body and the valve shaft increased, resulting in no action of the solenoid valve. Based on this experience, it is considered that there may be a problem with the solenoid valve controlling the paper cutter. Therefore, the standby solenoid valve was replaced and the machine was started again for test, but the paper cutter still did not act, so this possibility was ruled out
inference is the cause of the circuit. The paper breaking detection line of the printing machine and keep these properties at low temperature (below (4) 0 ° C) are shown in the figure. When the printing speed reaches more than 8000 sheets/hour, the paper break detection starts to work, that is, PLC (programmable controller) y17 outputs DC24V, and relay km8 is engaged. Once there is a paper break fault, the limit presser foot SL falls, making the relay km10 pull in, and the input point X22 of PLC gets DC24V through the normally open contact of km10, so that the machine stops in an emergency and does not damage the blanket, but at this time, the paper cutter does not act. Only when the printing speed exceeds 20000 sheets/hour, the machine will drive the paper cutting intermediate while stopping in an emergency Polymer will dominate, knife will cut paper "Relevant national departments take the lead in formulating relevant standards, laws and regulations, that is, the Y4 output of PLC is DC24V, so that km9 can be absorbed to complete this function.
when the printing speed is more than 20000 pieces/hour, use a multimeter to measure the voltage at Y4 point. Although it has been turned on for many times, it has not output DC24V, which is suspected to be a problem within the PLC. Because the manufacturer has not provided the corresponding PLC ladder diagram, it can not be further checked, and initially wanted to give up The maintenance is handled by the manufacturer, but considering the low failure rate of PLC, even if the failure occurs, most of it is outside rather than inside. So I started up again to measure the voltage at Y4 point. After more than a dozen startup tests, there was finally a multimeter that showed DC24V, so it was judged that the output point was in poor contact. Remove the PLC output terminal, find the plug position of Y4, close the two copper sheets, and then reinstall the output terminal. After power on test, Y4 output DC24V recovers, and the paper cutter acts again, so the fault is eliminated
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