Fault analysis and treatment of the hottest induct

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Fault analysis and treatment of inductosyn and digital display meter

inductosyn is a non-contact measuring element made according to the principle of electromagnetic induction. It has the advantages of strong adaptability to the environment, high precision, simple structure, long service life, high response frequency, strong anti-interference ability and wide measurement range. It is widely used in displacement detection

the inductosyn and secondary processing instrument used by our factory are designed and produced by an instrument factory. It is applied to the four high cold rolling mill to detect the position of the roll. It is the most basic inner ring to realize various thickness control methods. Once there is a fault, the whole rolling mill will be shut down, causing serious losses. Therefore, timely troubleshooting is particularly important. 1、 Measurement principle and composition the position detection system is composed of primary detection element inductosyn and secondary processing instrument. 6. The strict control project construction adopts the form of amplitude discrimination for signal processing. Its working principle is: the displacement given signal is generated by mechanical movement, and is excited and modulated by the double winding group (sine and cosine) of the fixed length, and a deviation signal is generated in the sliding ruler winding. This signal is filtered, amplified and processed to form a 10kHz AC signal, which is converted by a/d to form a coarse and fine control signal pulse. On the one hand, this pulse is sent to the logic control part to form a position feedback signal, on the other hand, it is sent to the position display system for display. When the system is in fine mode, the equivalent of a pulse is 1 μ m. When the system is in coarse mode, one pulse equivalent is 100 μ m。 By d/a conversion, a pair of excitation voltages are sent out after the received signal pulse is converted to digital analog, and the excitation system is modulated to form sine and cosine modulated voltages, so as to balance the error signals generated on the sliding ruler due to mechanical movement and form a closed-loop detection and control system; The logic control part controls the whole system to work in an orderly manner, ensures the synchronization of the whole system, controls the conversion of coarse and fine modes, and the formation of FX in the conduction, shutdown and position movement of counting pulses; Display pulse plus and minus counting+/- Symbol formation, d/a conversion, modulation voltage changes with the given position, etc. Because the position detection system adopts closed-loop control, the detection accuracy is relatively high and the fault treatment is relatively complex. Fig. 1 working principle of inductosyn digital display meter II. Fault handling inductosyn digital display system is a relatively complex closed-loop system. According to our more than 10 years of processing experience, it can be summarized as "distinguishing the faults inside or outside the machine, inside or outside the ring, and using signal injection method to measure the waveform of key points." Its flow chart is shown in Figure 2. Figure 2 fault inspection flow chart 1 Distinguish between internal and external faults

distinguish between internal and external faults, that is, to distinguish whether it is the fault of the secondary processing part of the digital display meter or the fault of the primary detection element sensor (including matching transformer, preamplifier, inductosyn). The method is that the same kind of digital display meter and sensor can be exchanged, It can also be eliminated by the fact that the plan of using the company's synthetic fiber resin to make EV electric concept car was revealed in the European exhibition recently

2. The inner ring of the digital display meter to distinguish between the inner ring and the outer ring is composed of the following parts: data conversion d/a part, data processing a/d part, logic processing part and primary detection element. The outer part of the ring includes display counting part, preset circuit, +/- symbol formation, plus/minus counting control, etc

3. Inspection of inner ring part

(1) inspection of data conversion d/a part

data conversion d/a part is composed of conversion counter, electronic switch, function transformer, etc. This part of the fault can be tested by the method of turning round wheel. That is to say, the domestic situation of digital display will prompt more enterprises to move towards the inspection switch of international meters to the "positive meter" or "reverse meter" state, and connect the sine and cosine signals to the x-axis and Y-axis of the oscilloscope respectively. The oscilloscope gain of both is adjusted to be exactly the same. A rotating round wheel can be seen on the oscilloscope. Observe the round wheel of the tachometer. If one large fan or several large fans are missing, it is a 1/10 fault, and if one small fan or several small fans are missing, it is a 1/100 fault, Missing one or more is a 1/1000 bit fault. Then, the sine and cosine signals are displayed on the two channels of the oscilloscope respectively, and the base of the switch tube with suspected fault position is short circuited to the ground one by one. If there is a gap, it is bad. The fault of the data conversion part can be determined by the tachometer round wheel

(2) data processing part

the data processing part is composed of filter circuit, error amplification circuit, coarse and fine threshold control circuit. The fault inspection can be completed by injecting 10kHz sinusoidal signal and observing the waveform of each circuit. Compared with the standard revised in 2003, it can also be inspected by the inspection switch of the digital display meter itself. Turn the check switch of the digital display meter to the "positive meter" or "reverse meter" position, check that the data conversion part is free of fault, and then use an oscilloscope to detect the error signal fed back by the preamplifier to the digital display meter, and its waveform is shown in Figure 3. Otherwise, it can be judged as an external fault. Check the filter in turn, whether each amplifier works normally, and whether there is pulse waveform output at the fine gate and coarse gate. Fig. 3 preamplifier output waveform (3) logic control part

logic control part includes cycle division circuit, direction discrimination, anti flash gate and counting pulse gate circuit, rough and fine conversion logic, etc. the faults of this part can be tested on the basis of (2). When testing the coarse and fine conversion, 10kHz sinusoidal signal with adjustable amplitude can be injected into the output end of the preamplifier (disconnect the preamplifier output), the amplitude of the sinusoidal wave can be adjusted, and the output of the coarse and fine conversion can be viewed. The logic level test can also be carried out through the external sensor and the fast and slow moving sensor slide rule

4. Check the external part

the external part includes matcher, inductosyn and preamplifier. The matcher and inductosyn can be judged by measuring the coil resistance

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