It is said that doing so can effectively prevent the cotton opener from choking the car

There are several ways to prevent choking on the cotton opener, most of which are implemented by hardware circuits.This method has the disadvantages of not being easy to maintain and not having high control accuracy.This article introduces an anti—choking vehicle device implemented using Siemens S7-200PLC software.

The characteristic of this device is that when the cotton opener has a tendency to stop turning, the cotton feeding motor is determined to stop the cotton feeding motor according to the reduced speed of the hand shaft, and this reduced speed can be set, and its working principle is as follows：

Install a non-metallic disc on the handle shaft, and a small piece of metal is inlaid on the disc.When the disc rotates with the handle shaft, the metal block passes above the proximity switch, and the proximity switch outputs +24V, resulting in a rising edge.When the metal block leaves the proximity switch, the proximity switch outputs 0V, resulting in a falling edge.As the handle shaft rotates, the proximity switch outputs a series of pulses.From the falling edge of one pulse to the falling edge of another adjacent pulse, this period of time is the time it takes for the hand axis to rotate for a week.After measuring this period of time, the speed of the hand shaft can be obtained.

When I0.0 changes from high to low to generate a rising edge, the disconnect delay timer T32 counts from 0.When I0.0 changes from low to high to produce a rising edge, the value of T32 is sent to the variable memory VW0.At this time, T32 is still counting, that is, the condition of T32>VW0 is established, and the value of T32 is sent to the variable memory VW2.When I0.0 changes from a high level to a low level and produces a falling edge, the hand axis rotates for exactly one week. The value in VW2 is the time it takes for the hand axis to rotate for a week. The unit is Ms. At this time, disconnect the delay timer T32 and start counting again from 0. The condition of T32>VW0 is not established. The value of T32 cannot be transmitted to VW2. VW2 still maintains the value before the falling edge arrives. This value is the time it takes for the hand axis to rotate for a week.

When the phenomenon of choking the car occurs, if you want to reduce the speed of the hand shaft to 15r/s and let the cotton motor stop feeding the cotton, then use the comparison command in the program to compare the actual speed of the hand shaft VW4 with the set stop feeding speed of 15r/s.If VW4 is less than 15r/s, the inequality is established. After the delay timer T37 is turned on for a delay of 2s, the PLC digital output terminal Q0.0 outputs a high-level relay J to suck in, causing the cotton feeding motor to stop feeding the cotton, thereby avoiding the phenomenon of the cotton opener being choked to death.When the speed of the hand shaft returns to normal, the inequality does not hold, the relay J is released, and the cotton feeding motor automatically feeds the cotton.The delay of 2s causes the relay J to absorb and close, in order to prevent the frequent movement of the relay J when the speed changes near the set value.

The device is not only suitable for cotton openers, but also for equipment with speed control requirements such as carding machines, and one S7—200PLC can control multiple equipment, which is low in cost and practical, and maintenance-free.