The automatic feeding system controls the discharge flow of the feeding mechanism through frequency conversion speed regulation, and measures the reduction of the weight of the material per unit time in the bucket Δd/Δt corresponding to the feed flow of the dosing, the dosing controller compares the dv/dt with the preset feed flow, and automatically corrects the feed flow by adjusting the speed of the feeder, which can maintain the accurate feed flow. When the weight of the material in the metering bucket is lower than the preset value, the control module will lock the feeder speed, keep the feeding mechanism to feed in volume mode, and open the feeding valve for rapid feeding. When the weight of the material in the measuring hopper reaches the high preset value, the charging valve automatically closes. At the same time, the proportioning controller automatically switches the feeding mechanism to the weighing mode.
020-34563445Automatic Batching system is a complete set of automatic equipment which realizes dynamic weighing and batching control through electrical control management and visual man-machine software configuration. The electrical control part of the system adopts Siemens PLC, which is programmed according to the production requirements. The software adopts the human configuration, according to the process requirements, through the monitoring system and PLC program to load the material to the weighing hopper weight, flow control, so as to achieve accurate measurement and batching. The system has strong stability and high cost performance, and can provide accurate measurement data and control means for production control and management of various industrial sites.
Feeding system according to the process requirements, according to the predetermined formula, a variety of materials according to the formula requirements automatic batching, batching into the automatic discharge, discharge to start stirring, stirring to complete the automatic discharge, and so on. It has automatic control function and weighing data management function. In the production process, it can be according to the process requirements, according to the predetermined formula, the material is added to the weighing hopper according to the fixed proportion weight value of a variety of materials, when the weighing is displayed to the amount (that is, the weighing and measuring of each material is completed), and then the material is discharged into the mixing machine inlet once or step by step according to the unloading procedure.
Batching through the cable to achieve a variety of on-site temperature, pressure, flow and liquid level parameters real-time detection and on-site motor feedback signal detection. According to the process requirements, the upper and lower limit alarm is set at the analog measurement point, the fault signal of the switch measurement point is warned, and the alarm is made by the sound screen of the operation station to remind the operator of necessary processing in real time.
In order to make the production stable and protect the equipment, many interlocking controls are widely used in the batching line. In this batching, this function is achieved through the LD section of the graphic programming software of the custom control scheme, which makes the pump and valve in the field start/stop and alarm under specific conditions. In order to make better use of the interlock function, the start/stop interlock button is also set, so that the device can be unlocked in abnormal circumstances to achieve industrial control. This interlock is used to trigger A21 to stop thickening EG to the tank when the tank pressure is too high (PAHH-04310A). A21_INTER and ALM_A21 are custom one-byte variables used to start/stop interlocking and alarm, respectively.
In the production process, it is also necessary to know the output, cumulative amount and the addition of some major parameters. For this purpose, it is defined in the FBD section of the graphics programming software for custom control schemes. The final polycondensation level of the device is adjusted by controlling the speed of the prepolymer pump SC-05240 through the controller LIC-05312 to adjust the feed amount, among which LI-05312 is calculated by the feed level of the reactor before and after the reactor (LT-05310 and LT-05311) through the calculation formula shown.
In the production, the sizing ingredients are programmed. Firstly, a quantitative EG (EG measured by mass flowmeter) is added to one of the slurry preparation reaction tanks, the slurry preparation reaction tank agitator is started, the corresponding refined terephthalic acid (PTA) is added according to the set molar ratio, and the prepared catalyst solution (CPC) is added in proportion, stirring for a certain time and waiting for use. This function can be achieved through the SFC section of the graphics programming software.
The single loop PID control is widely used in the batching, and the control parameters include: proportionality P, integral time I, differential time D, and control period Ts. In addition, a cascade loop is also used. That is, when the output of one controller is needed to change the given value of the other controller, the two controllers connected in this way are said to be cascaded. Both controllers have their own measurement inputs, but only the primary controller has its own independent given value, and the output signal of the secondary controller is sent to the controlled process. The main cascade circuits in this batching system include ester - liquid level control through mass flowmeter to feed pump speed, reaction kettle internal temperature regulation and viscosity and vacuum cascade control. Some of these loops have great hysteresis, so on the basis of conventional cascade loops, some languages are used to make them realize cascade control.
