Fatal error PLS SLC 5/03

If a want read some data files, for example N7:0.. not problem. But if i want write in a data files who's doesn't exist (by error on keyboard, double touch...etc) the plc goes in fault.. I must go online and clear the fault. How write in data files whose doesn't exist... i know that it's not possible, but i just want to prevent the fatal error of PLC...

How do that??

With RSLogix500, you cannot accept a rung with that type of error, so you would be hard pressed to cause a CPU fault by adding code that contained illegal addresses, unless it was an indirect address.

So that brings up my main question:

What are you using to do the reading and writing?

yes, i using a indirect adress to make that.

Well, with indirect addressing, you just need to be more careful.

If you want a possible alternative to that here are a couple of methods:

1. Accept the rung, but do not Test it until you have right clicked on the indirect address in question and verified its existence by clicking "Go To Data Table". The file monitor window should pop up with the indirect address highlighted by the cursor. If it does not exist, I believe it will put the cursor on the first element in the file (which it will also do if the element in the brackets happens to contain a "0"). So, in addition to that little check, go ahead and manually look at the address in the brackets [...] and make sure it is there. Then, test the rung.

2. Put a LIM test in series with your indirect address logic so that it will not be scanned unless the address is within the file limits. I use this method in one particular program of mine and it works very well. A LIMit test, is a range check, like a GEQ and LEQ in series, but in one instruction, in case you aren't familiar with it.

presently i using a LIM in series with my MOV like your said in your reply. It,s only the solution that a find to prevent the fatal error, but i must manualy check if the data files realy exist.

thanks you