Can't do a "Write Changes" with Proficy Machine Edition

I'm new to Proficy Machine Edition and I'm trying to "Write Changes" to an edited rung without doing a complete download. The help files say the function is on the Controller menu. I can't find a controller menu and the help for the menus don't show a Controller menu. There doesn't seem to be a shortcut either. There is a shortcut listed for PC but not PLC. Any help appreciated.

Not all processors support that, which CPU do you have?

A 374 I believe

The only 374 I know of is the IC693CPU374 as it is part of the old style 90-30 family and not the more modern PAC family or PC Control it does not support Run Mode Rung updates. You will need to do a Run Mode Store which downloads only any changed Block.
This is stated in PME's online help but one needs to read all the fine print.

Thanks Russ. That is the cpu and it doesn't support the write function. Rats!

You'll just need to be a little more careful about any changes you write to the PLC while it is running. If the change doesn't work out as you expect you'll have to rewrite the original logic instead of simply being able to cancel your edits.

In my opinion that's not a totally bad thing. Just as anti-lock brakes on your car can lead you to drive faster than should on less than optimum road conditions, having the ability to quickly undo your changes may make you less careful about thinking through the ramifications of those changes.