Material level sensing control circuit analysis

Granular materials often maintain a certain amount of reserves in the storage bins, and timely feed after the shortage, in order to maintain the continuity of the materials used in the production process. The infrared material level detector control circuit introduced here has the characteristics of low cost, easy production, and reliable operation. The circuit is shown in Figure 23.3. SE303 is an infrared photodiode, and PH310 is an infrared photodiode, which form a pair of level detectors. 555 constitutes a comparison circuit afterwards. J is a relay, SSR is a solid state relay, both can be used to control the feeding equipment as well as the sound and light alarm circuit.
When the material is under the infrared light detector, the emitted infrared light is received and turned on. 555 2nd and 6th feet become high potential, and the 3rd and 7th feet are low level output. Then J is sucked, the SSR is cut off, and the feeding device can be controlled to feed.
When the material reaches the position of the infrared detector, the infrared light path is cut off, PH310 is in the off state, 555 second and sixth feet are at a low potential, the third pin outputs a high level to make the SSR turn on, and the seventh pin is internally cut off to make J It is released and can be used for alarms and stop feed control.
Any 12V type or 9V type relay with coil current at 150mA, such as JRX-13F, JRX-12F, HG5021, etc. can be used.
The selection range is wide, and the output control current can be used within 40A. His selection should mainly consider the voltage and current capacity of the controlled equipment. It is a safe design method to use within half of the rated voltage and current of the SSR.
The power supply voltage is not limited to 12V, and it can work in the range of 6~12 as long as J allows. No-load current consumption other than J and SSR is less than 15mA.
The SE303 and PH310 are mounted opposite each other in a glass cover. The distance between them is less than or equal to 20mm. The small particles of the material can make the SE303 and the PH310 smooth surface smaller. Attention should be paid to two points. One is to prevent the serious pollution of the transparent surface of the glass cover from affecting the transmission of infrared light, and the other is to block the infrared light path after the material is in place. In actual production, the infrared detector and 555 can be put together to make a module of 20mm × 20mm and 7mm thick, and lead three wires (power, ground, and output) to J or SSR.