MICRO850 FIFO(FFL & FFU)

Hello Everyone,

I have to develop a FIFO program in Allen Bradley micro850 PLC.

The description is as below:

Three(3) sensors, where any of the sensor can be turned on first

One(1) push button, where when the button is pressed, need to reset the first sensor that detected previously.

For an example, there are sensor1, sensor2 and sensor3. Then Sensor 3 detected first, sensor1 detected second and sensor 1 detected third.

When push button is pressed, first detected sensor need to be reset, followed by second and third detected sensor.

Can anyone help me or clarify me on this matter.

Thanks in advance