Micrologix 1100

[learning engineer 0]

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

[Mickey 71]

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.

[Bill Linne 0]

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

[TimWilborne 108]

Also check to see if the Beijer is setup to write a default value at startup

[learning engineer 0]

PULLER1.RSS So far, i have not been able to resolve it; here is the program.

[Mickey 71]

I don't see anything in the PLC program. I would take a hard look at your HMI. ( I have never used a Beiger so can't help there)

[rpraveenkum 5]

May be some Indirect addresing causing this or Overwriting of memory module on power up

[TConnolly 13]

I concur, provided that is the complete program. To prove whether it is the HMI or not change the HMI to write to an unused register, such as N7:20. Then wait and watch.