QUOTE(Mickey @ Apr 28 2007, 08:39 AM) [snapback]53491[/snapback]
QUOTE(learning engineer @ Apr 28 2007, 11:31 AM) [snapback]53490[/snapback]
I am entering an integer value into N7:5. This value is not always retained, and often it chagnes by itself. what am i doing wrong?
(i am using Beijer E150 operator interace, to enter these values, but i dont think it has anything to do with this problem)
Thanks
Not going to change by itself. Possibly more then one thing writing to it( PLC program or more then one HMI?). Can you post your program and someone can take a look.
I would look for N7:0 being used as the control block for some other instruction (like a MSG for example) and therefore N7:5 is periodically being overwritten. If that's the case, writing a "foreign" value to N7:5 could also cause the MSG (or whatever it is) to operate erratically (or fail outright).
Do a search for N7:0, N7:1, N7:2, N7:3, N7:4, and of course N7:5. If any N7 address below 5 is being used for something that involves more than one word, you've likely found your problem.
Certainly could be another PLC writing data to that register, too. Or, an input module could be configured to write there. SOMETHING is overwriting your data, all you need do is find it. Been there many times, believe me!
Good luck,
Bill