Control system for conveying and metering of granules

Abstract

The invention relates to a control system for conveying and metering of granules. The control system comprises a PLC controller, a metering bin connected with the PLC controller and a cylinder solenoid valve, wherein the cylinder solenoid valve drives and controls the motion of a blanking baffle plate, the PLC controller is embedded with PLC programming software, a rectangular pulse generator which controls the blanking baffle plate directly through the cylinder solenoid valve is in a series connection with a blanking baffle plate control output point of the PLC programming software and comprises the pulse timer T0 and the pulse timer T1, which are in a parallel connection, the pulse timer T0 and the pulse timer T1 are respectively in a series connection with normally-closed contacts of T1' and T0' so as to realize reciprocal interlocking, a T0 output point is constructed as a control output point of the blanking baffle plate, and an input value of timing pulse width of the rectangular pulse generator is set to be in a range of 0 to 27 s in the PLC programming software. The control system provided in the invention has stable and reliable performance, can prevent occurrence of unexpected events, totally avoids the phenomenon of cutting-off of a raw material, eradicates potential safety hazards of cutting-off and stopping of a production line and is convenient and reliable.

Description

Technical field [0001] The invention relates to a control system, which is especially suitable for the control system for the discharge and measurement of granular materials that interfere with signals and have harsh environments. Background technique [0002] The pellet conveying and metering line supporting the polyester film production line, the feeding platform of the metering bin is installed on the platform of the extruder, and the raw material is usually provided by the raw material bin through the feeding baffle. Its working principle is: when the weighing of the metering bin is lower than the lower limit, the PLC output point M0.0 sends an instruction to open the blanking baffle, and the raw material from the raw material bin is discharged to the metering bin; when the weighing of the metering bin reaches the upper limit, the PLC output point M0.0 sends the closing command of the blanking baffle to stop the blanking, thus realizing the automatic feeding process. Th...

AI Technical Summary

Problems solved by technology

But this control device actually has some defects: one is that the blanking baffle sometimes does not move, when the metering bin is low, the PLC sends a 24V high level, but the blanking baffle is sometimes stuck due to fine materials, once The action is not turned on, resulting in failure to unload material, causing the production line to stop due to material outage

The second is that the 24V output by the PLC is sent through the solid-state relay SSR. Although the SSR has high reliability, it occasionally has a large on-state voltage drop and unreliable solenoid valve pull-in during hundreds of thousands of operations per year. Phenomenon, resulting in the blanking baffle can not be opened

At this time, the PLC has been sending a high-level signal. Due to the unreliability of the periphery, the PLC cannot reset itself, causing the final shutdown due to material failure.

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