Using change value and data view

[at6c]

I setting up a PLC to control a lathe spindle motor.  I tried using debug but I couldn't change any of the values.  I resorted to using physical I/O's to test the program which works fine.  Now I would like to know why I can't get debug to change the I/Os.  If I select change value in run mode the input is read (off).  I select write button to change value to on the value doesn't change.  Same in data view, read/writes are enabled so is override.  Why doesn't the input value change?  What have I missed.  Thanks.
George

[PLCGuy]

It has been awhile since I did what you are asking, but I think you need to goto Options, then click on Override Bits. You are talking about X or Y bits? To change the Y bit status make sure nowhere in the program you are resetting or holding them to a certain state. The option idea is for forcing the X bits.

[b_carlton]

The override function is only available from a dataview. The 'change value' button won't let you do an override.

Are you clear why an override is needed and what it does?

[at6c]

Guys thanks for the replies.  I got it to work, but I am not sure why it didn't respond before.  Your responses got me to go through the setup again and maybe I missed something the first ten or eleven times.  Slow mind and fast fingers are a bad combination.  Thanks again.
George