Example One: Machine Model: CYNCP — 320 CNC lathe, the system MNC862 Failure phenomenon: machine emergency stop alarm. The observation and measurement, machine trip caused no damage to the phenomenon of the line. PC, then find all the indicator light does not shine. This is a clear failure, you must first rule out the possibility. PC (programmable controller) All light does not shine, this situation rarely encountered in practice. Under normal circumstances some of the indicator does not light (it should be bright), imes New Roman ; mso-hansi-font-family: Times New Roman "> From this we can determine the light does not represent failure phenomena. all the light does not shine, it is natural to suspect that PC machines have been damaged. Power AC and DC fuses were not blown inspection. another look, and also found no abnormalities of the lines and components. For PC, internal inspection, some of the general can only do so in the absence of the internal circuit diagram and working principle described in circumstances, to more in-depth examination is difficult to judge. However, PC machines is a special order control for industrial micro-computer, it has strong protection, even under normal circumstances be damaged easily. Thus, further examination and PC machine-related input and output circuits, a problem not found. and then ask experienced technical personnel, suspected of causing the PC overloading ont-family: Arial; mso-ascii-font-family: Times New Roman ; mso-hansi-font-family: Times New Roman "> machine works and the internal self-protection function of the input and output lines disconnected . Thus, to disconnect the load 24V DC power supply, the boot, PC some indicator light shows that may not damage the PC machine. But when re-connected load, PC machine has all the lights went out. This shows that the PC aircraft DC power load may be a problem. remove the PLC machine DC power load line measurement, the resistance is only 500 Ω, obviously the value is low. The load control circuit for the tool change operation, shown in Figure 1. map SQ11 ~ SQ14 for the Hall switch. they suspect that the circuit Hall switch installation disc with pollution (ily: Times New Roman ; mso-hansi-font-family: Times New Roman "> This has happened many times). After washing, the boot test, PLC machine light is off normal, and no longer all light does not shine. Machine emergency stop alarm has been lifted. But the tool change action is still not normal. Further to determine whether the failure by ATC control the normal observation of similar actions that ATC machine: normal, each for a knife-bit, PC0000 No. input light is blinking about, shown in Figure 1. It should be noted that, when the change to the desired tool position, the cutter on the fixed to be in that position. At this time, Hall switch is in the (actually a bit of deviation) above the magnet, The Hall switch is connected to the state has been, PLC machine input indicator No. 0000 has been lit. Observed when the lights flicker on in this state as the base state from the next flash, every flash once, indicating a knife who changed his position. Hall switch action can be judged this normal? And then specify a Hall switch is damaged? Been finalized, one of the Hall switch is damaged, put a new post, ATC movements normal. Failure eventually ruled out. Analysis; machine emergency stop switch Hall effect is due to the circuit plate installed after pollution caused. This is because the PLC machine DC power overload, the current of about 480mA (24V projections o-hansi-font-family: Times New Roman "> ÷ 500, not measured). check this model (
Omron) DC24V maximum load current of 200 mA. Thus, over the load capacities, make self-protection circuit. but the value does not exceed the fuse of the fuse, so the output fuse is not blown. After cleaning, test the load resistance of 5 k Ω, so that the leakage current is reduced to 48 mA, less than its load capacity, and therefore its internal self-protection circuit does not operate, so that PC, indicator light, but still not normal ATC. only when the damage has been replaced Hall switch to normal ATC. At this time, family: Times New Roman "> test (to remove a load line) at both ends of the resistance of the load line: positive (black sheet document then the positive terminal connection lines DC24V) for ∝ value, the reverse is more than 20K. When the PC machine does not work (that is, when self-protection work), its output control all the circuits are not working properly. PC OUT 0507 no output, relay KA2 work, so the trip computer input 301 NC no input, resulting in machine tools emergency stop alarm. The fault, in fact, the two fault Times New Roman ">, the pollution caused by the machine emergency stop circuit alarm and damage caused by the ATC Hall switch is not normal. Example Two: Machine Model: CYNCP — 400 CNC lathe, system MNC862 failure phenomenon: spindle can not be started, or the tool change can not be. Computer self-test procedure to determine the input and output as normal. Further X, Z axis operation, are operating normally. Observation screen: When the implementation of the spindle start (that is, Reversible) program 895 G00 S1 M3 Roman ; mso-hansi-font-family: Times New Roman "> or ATC procedures (that knife both positive and negative), 90Z G00 T17 program, the computer program to stop running. At first inspection procedures and the computer from starting but not the results, only computers and programs from outside the circuit to start. observe the PC, the input and output points, found abnormal. normal, the output point 0507 and input 0014 LED should have been lit. This found that the output point of 0507 illuminated and the input 0014 is off. KA2 suspected faulty relay controlled, as noted in 2 patients (2 machines or less the same circuit) and Figure 4 family: Times New Roman ; mso-hansi-font-family: Times New Roman "> below. This will lead to 0014 lights not working. Observation KA2 working. So PC-suspected faulty. but the observation of PC machine power indicator POWER, RUN lights indicate normal operation, and its failure indicator ALARM, ERROM not lit, it shows the work PC, it is normal. PC-DC24V power supply test and found nothing to do with the normal work of the conclusions contradictory. A closer inspection found that the majority of PC-input plug-in has been set aside ( Times New Roman "> the row terminals have DC24V output), be installed after the test, working properly. Troubleshooting. Seen in this light, after the input terminal is not allocated to the state of light from the PC, reflect this. This failure showed the computer can not properly run the program, easy to make people think that program or computer malfunction, and in this great effort, resulting in detours repair the situation. But a closer one would like, the computer can not run the program properly because no more than two: 11 internal, that is, computer hardware and software itself; 21 external, that is computer-controlled appliances. generally start or from external components. the computer is a highly intelligent device, its foreign Control is very good. When the implementation of an action, the </ Span> need to know the implementation of the external device. The performance given by the PC, a response signal, when the computer receives the response signal, and then decide whether to down enforcement procedures. Code signal is a signal from the computer, on the spindle rotating, High-speed control. Electrical implementation of the completion of this instruction from the PC, back to the computer for more than 160 ms FIN signal that the response signal, the computer receiving the signal, the turn-off SF signal, and procedures for the implementation of the next sentence. Figure in SF signal S T code output function. InS function code output, the delay 160 ms output signal SF, machine code and execute the corresponding T to take action. Spindle motor, Turret motor action is issued by the PC based computer command control signal, and through its DC24V power supply to achieve. DC24V power supply due to the failure terminal is pulled out, but not execute computer instructions, PLC machine, will not return a response signal, the computer program can not continue down the implementation of course.