saving and erasing values plc rs logix 5000

[khewes]

hello all,

im working with an allen bradley 1769 series plc

on an indexing table, I take a picture with a camera and determine whether parts are good or bad. at the same time on the next index location, i remove parts from the table to their respective bins, good or bad

because the parts have to be toleranced so tightly and the fixtures do not all fall within an acceptable tolerance, i need to know what station is where, and thus i cannot sequence thru the index blindly because the table may start anywhere... if that makes sense

so i need to remember what parts are good an index later, without a sequence number to start at...but i cannot think of any way to do this without a sequence taht is specified

Im having trouble wording this so please ask questions if you do not understand my problem

 

[AutoMax]

Is the index table running on a servo?

 

[cwal61]

1. Do you need help to track parts on the table?
2. Do you need help to track part in the Bins?
3. Do you need help to track both?
4. Can you draw a diagram of your situation?

The diagram will help us understand what is needed.

 

[BlueAltezza]

You already stated what you need to do- know where the fixtures are. I'm guessing the number of fixtures is constant?

There's no way to perform a "home" type procedure upon startup? Is your PLC controlling this table? To home, you can just put an identifier and sensor on one fixture. Then as your table indexes, you keep count of the fixtures and keep the statuses with a fifo / bit shift.

If your PLC isn't controlling the table, obviously that won't be a good solution and the table's controller would have to be modified to start at the same position and tell the PLC that isn't ready.

Now if homing the table isn't an option, I think there's 2 other methods:
First, you could still use the sensor on one fixture. You just run the system normally until that fixture arrives, then you start your official shift registers. This might not be viable pending how many fixtures there are or how many times they shut down, etc.
The second method, but more expensive solution could be using another camera and just putting numbers on each fixture. This makes the programming and tracking a little more complicated but you'd always know what fixture you're inspecting.

 

[khewes]

Blue altezza,

You were on the money, we put numbers on each fixture, our current camera was able to handle it.

thank you everyone for the replies, sorry im late getting back its been a hectic week