FIFO control with FX3U

[plcdp 11]

Hello, I am trying to automate a merging conveyor line where 3 lines feed on to one conveyor. There is a photoeye for each incoming line and gates to control product flow. I would like this to operate with a FIFO type of control. Is the SFWR or SFRD commands the right way to do this? If so, could someone explain how these commands work because the manual is a bit confusing to me. Thanks in advance for any help. plcdp

[Inntele 60]

Hi, I didn't understand why are you need FIFO control for this task... But yes, SFWR and SFRD commands are FIFO organization commands if you want to write and to read a single value. If you want only to write value or array of values you can use WSFL or WSFR instructions. The work of both type of commands is described in detail in the document: FX3U/FX3UC/FX3G ProgrammingManual (Basic & Applied Instructions Edition) JY997D16601 Version F. Edited 4 Feb 2010 by Inntele

[plcdp 11]

Inntele, What I meant was I wanted the task to operate with a FIFO principal, and don't know the best way to do it. If you were to be doing this task how would you go about it? Thanks for the help, plcdp

[Inntele 60]

It's without problem, plcdp. If you need serious help with certain result, I need to know conditions of the task, the volume of my work and the amount

[plcdp 11]

Basically, I have a 3 bottle lines I want to merge into one single line. I have gates set at the merging point of all three lines. and I have a photoeye to see the bottle coming on each line, and one to see the bottle pass on the single conveyor to tell the plc it can let the next bottle in. I need them to be let through on a first come first out basis, but not to allow any 2 bottles to be let through at the same time. Thanks again for the help, plcdp

[Inntele 60]

It is very simple task. But you are right, here is need to use FIFO with SFWR and SFRD instructions. In the document about which I wrote you could find all necessary information how to work with these instructions.