Furnace control system of vacuum sintering furnace

The control system of this equipment includes all control instruments and actuators. This device has a high degree of automated operation, which is also one of the important differences with the ordinary vacuum sintering furnace. In order to ensure the reliability of automatic operation, the selected control instruments of this machine [including temperature control instruments, pressure control instruments, vacuum pressure sensors, programmable logic controllers (PLC), etc.] and actuators (including pneumatic main valves in vacuum systems) , Pneumatic isolation valves and pneumatic adjustable throttle valves, gas solenoid valves, etc., as well as pneumatic components) are selected by the world's brand-name manufacturers.

(1) The control center of the equipment is an intelligent temperature control instrument (advanced import instrument). The instrument takes time as the main coordinate and can compile more than 10 temperature control curves (can be a group of programs whose total segment number does not exceed 99). There are two sets of PID parameters that can be selected in the program to suit different temperatures. The meter will directly control the output power of the heating power source according to the thermocouple input signal and the set temperature value and the heating rate, thereby ensuring a smooth temperature rising curve and good temperature following characteristics. In the temperature program of the instrument, 8 different control event signals can be set in the program segment as required. When the program is executed, a corresponding control event signal will be issued in time to perform other necessary control operations synchronously. These control operations are required for integrated vacuum sintering furnaces.

(2) Programmable logic controller (PLC) is the control center of the equipment working state, using OMRON products. The operation command output by the controller is completed according to the control event signal and operating characteristic program transmitted by the temperature controller. In the device, a single event operation programming method is used for programming. The correspondence between the event signal and the completed operation function is as follows: As the PLC controller has extremely high control reliability, so long as the logic program is compiled correctly, the state of the equipment will be accurately and timely controlled, and the required equipment is completed. Functional operation and safety interlock. The logic control program of the PLC has been solidified in the PLC controller at the time of shipment from the factory, and the user cannot change it in principle.

(3) Furnace pressure control system. Some pressure control of some temporary and non-rigid requirements in the furnace, using vacuum pressure switch to complete. For example, the starting vacuum level of the Roots pump, the starting vacuum degree of the wax receiving system, the rapid inflation pressure, and the hydrogen starting pressure for removing the PEG at normal pressure all use the corresponding set point vacuum pressure switch. The switch signal will be sent to the PLC to complete the operation of the chain function. For furnace pressures that require stricter control and need to be continuously controlled, for example, pressures in the interior of the low-pressure carrier gas during dewaxing, carbon atmosphere control, and furnace pressure in the final-fired partial pressure sintering, etc., are directly related to the operating conditions and are directly controlled by the PLC. According to the event signal control dedicated pressure control system to complete.