FIFO Check

The_Wanderer

Member
Join Date
May 2003
Location
Waterford, Ireland
Posts
96
I have a machine being designed at the moment, and am trying to get a head start on he programming, as the lead time is (of course) very short. I have no ladder written as of the moment, but feel that a FIFO system will be the way to go. Unfortunately, I haven't used FIFO before, and am not sure of the workings. I would just like to get some opinions as to whether or not I am heading in the right direction before plowing into the actual ladder.

PLC: Mitsubishi FX1N
HMI: Mitsubishi E200

Machine: The machine is a rotary table tester. 6 stations, not all of them used. The operator loads a part, presses start, and the table indexes 1 step. The finished part eventually omes back to the operator (they wouldn't pay for an automatic unload/reject at the final station). A good part is placed in a box, but a reject part must be placed down a chute. The reason for reject must be displayed on the HMI.

The way I think this should be done is this:
At the start, place a single bit (part present) in a data register at the beginning of the FIFO stack. At each station, have the program look at the corresponding Data Register (Station 1 reads D1, does its tests, writes results back to D1; Station 2 reads D2, does its tests, writes results back to D2; etc.). When all stations are done with their tests, shift the registers in the stack up 1, index table, repeat. At unloading station, read the final code in D6 and display text according to results.

Am I on the right track? Any suggestions?
If this is the way forward, I just have to figure out the syntax, and which exact commands to use in which order (Manual has 2 commands that need to be used together-- read FIFO, write FIFO). While I'm sure the manual is helpful to those that have used FIFO, it is slightly confusing to me...

Starting work on this today, when I get a decent attempt at the ladder, I will post for (dis)approval :p
 
FIFO using Mitsubishi

Hi wanderer,

I think your question is very similiar to mine. Two months ago I got headache of solving the FIFO logic until those experts came to help me here. And now my machine is running very successfully, thanks to those guys who help me through.

So, i suggest that you read through my thread and Im sure it would help you too. good luck! :D

http://www.plctalk.net/qanda/showthread.php?threadid=4527&highlight=sutton
 

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