Analysis and inspection of the structure of the CNC lathe

The unit adopts upper and lower two-layer structure. The upper layer is the control circuit; the lower layer is the motor driven main circuit. 1 is the principle of the motor drive main loop circuit. When the control circuit is normal, the contactor MCC and the relay RLY are connected, the main circuit is energized, and the pulse width modulation signal is input through CN3-1, 2 and CN4-9-15 to drive the servo motor to move.

TM is a 50VloA six-unit power module, which is a consumable part. When the servo unit is over-current, it should be checked first. TH is a temperature detecting element that is turned off when the temperature is higher than 70 ° C, and turned on when it is normal. TR is a discharge transistor. CN42 is the discharge trigger signal input, CN4-1 is the discharge signal output, used for discharge circuit state detection. Rl and RZ are U and V phase current sampling resistors, respectively.

The current feedback signal is generated by the CN3-12 smart signal input control circuit. R, is the main loop current sampling resistor, CN4-7-8 sends the current signal to the control circuit. CN4-33-5 sends the power supply to the control circuit, CN3-7 is the 20VDC.2 which is the control circuit power supply part. The power supply consists of two parts.

One part is a power supply for a control circuit composed of Tl, 7805, 7815, 7915, etc.; the other part is a power supply for a pulse width modulation signal amplifying circuit composed of TZ or the like. This circuit is relatively simple. I will not go into details here. Communication between the central control unit and the servo unit takes place via CNI. CNI-7 is the output signal of the servo unit ready (DROY); CNI-12 is to allow the servo unit to run the signal input. The remaining pins (20 feet for CNI) are pulse width modulated signal inputs or alarm signal outputs.

When the circuit analysis and maintenance are normal, the 5 pin of PCI is low level, the 6 pin of IC16 (75189) is high level; the servo unit has no alarm, the smart foot of ICS (74LS148) is low level; when the power supply circuit is normal When IC12 (74LS00) has 3 feet high, IC14 (74 to 20) 1 pin and IC18 (74 Q10) pin 2 are high level, IC14 pin 4 and IC18 1 when the discharge circuit is normal. The feet are all high, the central control unit inputs the allowable running signal (active low), and pin 5 of IC14 and pin 13 of IC18 are high.

The output of both NAND gates is low, the 1 pin of Iclo (74璐00) is high level, the input signal of IC17 (75452) is high level, the output is low level, RLYI pulls The main circuit MCC pulls in. CN3-8 is connected to CN3-7, that is, IC16 (75189)'s 10 pin is high level, fl pin is high level, IC14 input is high level, 8 pin is low level, CNI one 7 is low level, that is, the servo unit outputs the DROY signal, and the pulse width modulation signal is input.

L, HV alarm servo unit quickly releases excess energy through the discharge circuit during deceleration. When the voltage or current of the circuit is too high, HV or Iå…€ alarm will occur. This circuit uses a special thick film circuit. The circuit is relatively simple, and the alarm is rarely seen during actual use. Once it appears, first check the periphery of the thick film circuit. The circuit and the discharge transistor TR of the main circuit, the discharge resistor DCR, and the like.

System program module, as shown in Figure 2, the system main control module input maintenance summary print {according to its repair and deletion, retreat and retreat, the class name is changed, it is changed, chasing each assembly, difficult to test, when the number is changed, the number is the number of fingers. Each of the performances of the force index is the result of the FBD test results. The number of the flats is divided into the rate of the district. The scores of the O-volumes are all recorded in the volume of the records.

Conclusion In the process of writing, the system always insists on the simplification of equipment, the universalization of applications, the intelligent operation, and the small amount of input. In practical applications, it truly serves the majority of teachers with the development of the economy. The increase in education investment by the state and society, the update of equipment in our school and the popularity of high-end microcomputers, as well as the improvement of the computer level of teachers, will soon be replaced by new systems.

(Finish)

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