JPS62249812A - Conveyer traveling distance control method - Google Patents

Abstract

PURPOSE:To improve reliability, by determining a traveling distance per pulse based on a number of pulses during the time in which a conveyer reference point passes between the front edge and the rear edge of a conveyer and controlling the travel of the conveyer by the measurement of a number of pulses for converting a set distance to a number of pulses based on the distance determined. CONSTITUTION:A number of pulses generaterd by a pulse generator 5 are counted and stored in a register 7, the pulses being generated during the time in which the reference point 2 of a conveyer 1 passes through a front edge sensor 4 after it has passed through a rear edge sensor 3. A traveling distance per pulse is calculated by a calculation circuit 8 to be stored in a register 9. In the next transportation a transportation distance which was stored in registers 10 is read out and the traveling distance is converted (11) into a num ber of pulses based on a number of pulses per unit to be stored. In transporta tion, a number of pulses 5 after the reference point 2 has passed through the rear edge sensor 3 are compared (14) with a number of pulses 12 for controlling the travel of the conveyer 1. With this arrangement, an accurate traveling distance can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for controlling the distance that a reference point of a conveyor moves from a fixed position in a conveyor that conveys objects in one direction.

(Prior Art) As shown in Japanese Patent Publication No. 52-2552, when a belt conveyor is used to convey objects, pulse control is performed for the purpose of detecting the position of conveyed objects. A constant is used for the moving distance per unit pulse because there is no need to control the movement of the object, and the accuracy of the position of the conveyed object is also not necessary. Furthermore, when it is necessary to accurately detect the position of a fixed part of the chain on a chain conveyor, a detector is placed at the detection position and the position is detected by the detector.

(Problem to be Solved by the Invention) When detecting the position of a fixed part of a conveyor belt or chain, the control method using a constant for the moving distance per unit pulse described above If elongation, deformation, or wear of pulleys or gears occurs, the distance traveled per unit pulse will change, impairing the accuracy of position detection, so limit switches should be placed where position detection is required. , a detector such as a photoelectric switch was installed, and the only way to detect the position was by using the detector. However, in the method using a detector, if the detection position is changed or increased, the detector itself must be relocated or expanded, which requires a great deal of cost, effort, and time. Furthermore, in places with poor environmental conditions such as temperature, humidity, and dust, the detector is likely to fail and lack reliability.

(Structure) The present invention is a control method for solving the above problems, and includes a conveyor reference point, at least two detectors at the conveyor front end and the conveyor rear end that detect passage of the reference point, and a conveyor pulley axis. A pulse oscillator to detect the rotation speed in pulses, a register to store the number of pulses, an arithmetic circuit to calculate the travel distance per unit pulse, a circuit to convert the distance setting to the number of pulses using the calculation result, a set value and Consists of a circuit that compares current values.

(Function) The present invention will be explained below with reference to the drawings. During a certain conveyance, the constant flow from the time when the rear end reference point detector 3 detects the passing of the reference point 2 of the conveyor l until the front end reference point detector 4 detects the passing of the reference point 2 of the conveyor l. The distance is determined by measuring the number of pulses generated by the pulse generator 5 while the reference point 2 moves and storing it in the register 7. Next, from the number of pulses and the distance between the reference point detector 3.4, the unit pulse is calculated. The moving distance of each hit is calculated by the calculation circuit 8 and stored in the register 9.

At the next time of transportation, multiple distance setting values 11.12...fLn
The data is read from the register group lO in which is stored, and the distance setting value is converted into the number of pulses by the conversion circuit 11 using the distance per unit pulse obtained during the previous transport and stored in the register 9. Register the number of pulses stored in the register group 12 after the 0th conveyance starts and the conveyor reference point 2 passes the reference point detector 3 at the rear end of the conveyor! By comparing the distance setting value stored in 3 and converted into a pulse number by the comparison calculation circuit 14 with the contents of the register 13, the distance that the conveyor reference point 2 has moved from the installation position of the rear end reference point detector 3 can be determined. can be detected accurately.

(Effect) By measuring the number of pulses generated while moving a certain distance and constantly monitoring the distance traveled per unit pulse, the distance traveled by a specific part of the conveyor due to pulses can be calculated by measuring the elongation of the belt or chain or deformation of the pulley. Accurate detection is possible without being affected by As a result, the number of detectors is only two, the front end reference point detector and the rear end reference point detector, eliminating the need for a detector for position detection, and reducing the occurrence of production failures due to detector failure. In addition, what used to be necessary to relocate or add a detector to change the detection position or increase the number of detection positions can now be done simply by changing or adding register settings, reducing the time spent on the same purpose. cost,
Labor and adjustment time can be significantly reduced.

[Brief explanation of drawings]

FIG. 1 is a control block diagram for implementing the method of the present invention. 1... Conveyor, 2... Conveyor reference point, 3...
Rear end reference point detector, 4... Tip reference point detector, 5
...Pulse transmitter, 6...Electric motor, 7,9.13.
...Register, 8...Arithmetic circuit, 10.12...Register group,! ! . . . conversion circuit, 14 . . . comparison calculation circuit.

Claims (1)

[Claims] For conveyors that transport objects in one direction and need to control the movement of a fixed location on the conveyor, a pulse transmitter is installed on the non-driving pulley shaft of the conveyor, and the passage of a reference point provided on the conveyor is detected. Reference point detectors are installed at the front end of the conveyor and at the rear end of the conveyor, and the number of pulses generated while the reference point of the conveyor moves a certain distance between the reference point detectors during a certain conveyance is measured, and the unit pulse is calculated. Calculate the travel distance per hit, store it, and convert the set distance into the number of pulses from the set distance and the stored travel distance per unit pulse for the next conveyance, so that the reference point is the reference point at the rear end of the conveyor the next time it is conveyed. A conveyor movement distance control method characterized by controlling the movement distance of a conveyor reference point by comparing it with the number of pulses after passing through a point detector.