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That's somewhat a loaded question.  Practically that depends on the project.  I agree that giving preference to such modules in your design is a good best practice; however, deciding which modules to put where depends on what you need for your situation.  We don't do a lot of motion control so I cant speak to that.  We do have a variety of communication modules, but that is highly dependent on the project.  I would make sure my comms modules get priority for being located in the main chassis.  I also would allow for expansion and growth of such modules in the future.  Then practicality kicks in. For example, often our main PLC is located close or in the MCC room.  That makes it highly efficient to locate the I/O modules associated with motor control in that chassis.  Often of our other I/O is spread about the process and remote cabinets are used for that.  I'm sure Rockwell doesn't really like my preference for Flex modules over point I/O, but the stupid way they arranged the wiring on those makes them an electricians nightmare (and thus mine also).  I guess to sum it up:  best practices as you mention are great, but each project must be evaluated within its own criteria to make sure the best practices are "best" for it. 

My first thought was that deleting the Main routine and inserting a new one may have messed something up.  I tried it on a new program (deleted the main routine and inserted another) and it still set the new routine as the main routine.  I still think this is your best bet.  You should be able to just look at it and tell.  If it does not have a little 1 marking it then it is not set properly.  I'd bet my last post that this is the problem.  See how confident I am?

Bravo again Michael!  We all get those blinders - especially with the client over your shoulder or at 3am. Here are some items to look at: 1.  Have you defined a main routine in your task properties? 2.  If you are using more than one routine, is their a JSR to the other routines from the main routine?

Michael!  LOL I would also be a rich man! Online and calling the routine (JSR in Allen Bradley)  have both been mentioned and the fact that you can toggle your output and dont have to force it on/off indicates that your logic is not being scanned.  Also - you didnt use the same address on two outputs did you?  Big no-no!  Last one wins...

Flashing fault LED indicates major fault.  Odd to see that for the first time with a older program.  If it is faulted then the program is not running and the outputs will be (most likely) off.  Serial programming with a USB cable can be fun.  Some just don't work.  I would suspect that since that cable is made for the PLC then it should work, but... maybe not.  I would try going into your window devices and see what comm port that device has grabbed.  That is really the only thing you have to setup manually with the auto config.  I will automatically and reliably go through all of your baud, error checking, etc settings.  The comm port does need to be correct.  You will need RSLogix500 to see the program and reset the error, but with a 1000 you should be able to get the micro lite version and do what you need to do.  There is a link to it on this site. 

I must be missing something.  Is the processor you are trying to connect to not connected via DF1 and Ethernet I/P?  named MonoFloBoxSnap... IP address 192.168.2.10

Excellent point Joe!  You did mention downloading over the existing application anyway but if this is a working system, it is always best to upload and have the latest revision saved.  You may think you have the latest revision, but good practice is to make sure.  If this is a new PLC and you just want to dump your program into it and dont care about the existing program then a firmware change is ok.  Your local rep or a local integrator can help you upload the existing program if you cant get it on your PC.  Also they might be helpful for your first firmware upgrade. 

I dont see an "X" where it matters.  You have your cursor on the DF1 path that I was referring to and you should be able to connect through that path.  The "X" that you refer to is via the Ethernet I/P path and is not a valid path for you to connect to that processor via DF1 (RS232).  You will need to do an firmware upgrade to the processor before you can download a rev 19 version of the project. 

Looks like a lot of different issues you are having.  First it looks like the processor is version 17.  Second it looks like RSLinx is connected via ethernet I/P to the processor (RSLinx lite is fine) but you are trying to connect RS232 by taking a path through the Ethernet I/P link.  I think if you went two items up to the "00 Compactlogix processor" item you would be able to connect via Ethernet I/P, but you would still have a versioning problem if 17 is not loaded.  If you want to connect via RS232, then you would need to follow the AB_DF1 pathing to your processor. 

Interesting.  Other than being harder to read, I had not heard that extended branches and branches as you show would cause additional scan time.  I guess if you were to look at it in mnemonic view you would see additional commands that the processor has to scan so it does make sense.  I cant imagine that you would be talking about anything significant.  Maybe microseconds added to the scan?  I would be more concerned about all of the unlatch instructions I see.  With that many unlatches it would indicate that the program has latches and unlatches throughout.  That gets ugly for troubleshooting and modifications.

Well the done bit shows that its off in the picture, but you know you cant always rely on the colorful things that the software has for you.  Thats why I would check it with a new rung right above it to make sure the dn bit is as you assume it is - off. 

It could be that your DN bit is actually set by the time it gets to that location in the logic.  Try putting a rung with a latch statement above that rung to see if the done bit is set and inhibiting your ADD from working.  Good call on the missing JSR Michael!  (Hmmm no pun intended)  We have all done that one I'm sure. 

both your tasks are 20ms rates and the event is called from those tasks so I dont see where you could be having the issue I described.  Is it possible that you changed the communication configuration when you downloaded?  Should have been pretty easy to autosync the serial though.  Did you try setting the serial configuration in RSLinx up again when you lost comms or did you just use the configuration that you already had?

Haven't looked at your program yet, but check your task scan rates.  I brought the scan rate of a periodic task way down when I was playing around with a bench processor and it didnt allow time for communications.  It was easily solved by putting the processor in program mode.  

Probably one of two things.  Could be a faulty EEprom module, but since it loads up when you take it out I doubt that.  Check incoming power to the power supply, and if OK then replace power supply and see if problem goes away.  Obviously if it goes away then the PS is to blame.

Yeah it was what we recommended our students use.  So maybe Rockwell is feeling sorry for Siemens not having a bigger market share in the US?  Seems counter productive to me.

Keeping up with Rockwell on this is like following a moving target.  Sometimes I think the word free is painful to them.  This software has been great for people wanting to learn PLC's and it gets them started on their software.  Seems like a win win to me.

You probably have two separate issues here.  First as has been mentioned check your solenoid for current draw and backlash protection (ie, diode for DC, MOV for AC).  Second...  Water in the panel?  Not only will that kill the PLC, but you may have fun corrosion problems down the road with other components.  Next time you may want to tell them to open panel and make sure the PLC gets good and clean!  Sarcasm can be fun in an industrial environment.

If you are still evaluating whether or not to use the Micro820, then I would suggest searching this forum for past experiences.  I did that recently and decided to stay with the 1100 and 1400 for my project requiring a cheaper PLC.  To summarize my findings, the increased time required to program the Micro8xx was enough to justify a higher priced PLC.   If you bill your time, then PLC cost + time will be more expensive with the Micro*xx.    

Interesting.  My understanding is the only time you have to worry about the COP statement is when you are copying information that might change during the execution of the statement.  That should be limited to I/O, produced consumed data and data that might change due to a periodic task interrupt.  Those would all be instances where data might change during the instruction execution, but should not be affected by placement of the statement in the program.

What you have looks good to me.  My understanding is that the Logix scans left to right, top to bottom.  Only the I/O updates are asynchronous.  Somebody let me know if I'm wrong on that one!  You could alternatively put all three instructions you have in series.  I still cant get past too many years putting them in branches like you have. 

Even though it was my suggestion, Im not big on VB on the plant floor.  I think it over complicates things.  I would suggest seeing if there is a SCADA package that will meet your needs.  I know that Ignition by Inductive Automation would handle what you want, but it may be overkill.  You could talk with them about their smaller limited client versions and see what the cost would be.  Others on here may have other SCADA suggestions.

Not to mention that Rockwell aggressively pursues pirated software.  You may want to plan on a discussion with their lawyers.  They do not play around where their software is concerned!

I dont think you will be able to directly interface powerpoint with an OPC server.  You might be able to create a VisualBasic application that will interface with the PLC and also be able to display the powerpoint and cycle through the pics.  If not, you should be able to display images with VB. 

This looks interesting, but it would be better if you posted the full link.  I never like clicking on a link blind!  This isn't twitter where you have a character post limit.