(1) Machine tool operation panel control.
Send the control signal on the operation panel directly to the interface signal area of the numerical control system to control the operation of the numerical control system, including M, S, T functions.
1) S function processing.
The spindle speed can be directly specified by S two-digit code or four-digit code. In the PLC, it is easy to directly specify the speed with a four-digit code. For example, the highest and lowest speeds of a CNC machine tool spindle are 3150r/min and 20r/min respectively. CNC sends a four-digit code of S to PLC, converts the decimal number to binary number and sends it to the limiter. When S is greater than 3150, The limit S is 3150; when the S code is less than 20, the limit S is 20. This value is sent to a digital/analog (D/A) converter and converted into a corresponding output voltage of 20~3150r/min as a speed command to control the speed of the machine tool spindle.
2) function processing.
CNC machine tools can manage the tool magazine through PIC for automatic tool exchange. The content of the processed information includes the tool selection method of the tool magazine, the cumulative use times of the tool, the remaining life of the tool and the number of tool sharpening, etc.
3) M function processing.
The M function is an auxiliary function. According to different M codes, it can control the forward, reverse and stop of the spindle, the gear shift of the spindle gear box, the gear shift of the spindle gear box, the exact stop of the spindle, and the opening and closing of the cutting fluid. The clamping and releasing of the chuck and the taking and returning of the tool by the tool change manipulator.
(2) The control of the external switch signal of the machine tool. Send the control switch signal of the machine tool to the PLC, and output it to the control object after logical operation. These control switches include buttons, travel switches, proximity switches, pressure switches and temperature control switches.
(3) Output signal control. The signal output by PIC is controlled by relays, contactors or hydraulic and pneumatic solenoid valves to control the tool magazine, manipulator and rotary table, in addition to the control of cooling, lubrication and oil pump motors.
(4) Servo control. Control the enable signal of the machine tool spindle, servo feed and tool magazine drive to meet the conditions of the servo drive.
(5) Alarm processing control. When a fault occurs, the PLC collects the fault signals of the strong current cabinet, the machine tool side and the servo drive device, sets the corresponding alarm flag in the alarm flag area, and the CNC system displays the alarm number and alarm text to facilitate the diagnosis of the fault.