Abstract
When tomato flow is disturbed at tomato packing center, it causes damages on tomatoes and machine troubles. Also, it makes troubles on the management at the center when tomato counter does not work normally.
Therefore, in order to dissolve these troubles, a trouble detector at tomato counter, using integrated circuit (IC) or micro-computer, was designed and examined.
As the sensor, two micro-switches A, B with distance H were installed as shown at Fig. 1, and four pulses (A, B, frequency divided pulse C and delay pulse D) were selected to detect the abnormal pulse combination (Fig. 4).
Truth table of the four pulses is shown at Table 2, and normal logical equation was shown as N=BC(A+AD)+ACD
Logical equation of tomato flow stagnation was simplified as Z=CD.
Judging of any trouble in detail is possible, but it is reasonable from the point of cost performance to display the information of the three states that are normal (N), tomato flow abnormal (Z) and other abnormal (S).
Logical circuit of tomato flow abnormal signal Z using IC was designed as shown in Fig. 5, and was examined to be successful.
Next, the trouble detector using microcomputer (SDK-80) was tested. Program lists for stagnation detector and for switch trouble detector are shown in Table 3 and 4.
The memory of these programs for about one hundred detecting cases will need approximately 1100bytes.
The cost performance of this detector is better than a detector using IC since as the scale of plant becomes larger.
