RMCTools "Unexpected failure while downloading"

Hi all,

I've run into an error I haven't seen before while attempting to download the “Programming” tab of RMCTools to an RMC200 Lite I just got in. This occurs anytime I perform the “Download Programs to Controller” action, even if there are no changes made at the time. Below is a list of things I have attempted:

- Updated RMCTools to the latest version
- Restarted the controller
- Reset the controller to defaults
- Created a new project

All of these attempts did not solve the issue. Attached is the message I am given:



I've just sent an email off to Delta but I'm curious if anyone else has run into this issue in the past. I'm not even 100% sure if this is a RMCTools or RMC200 issue, due to the vague wording of the error.

I have never seen that. Are you connected over Ethernet or USB?

Just found the issue and came back to see your message. I was connected with my PLC over ethernet to the RMC. Guess I've never attempted to update user programs while I was!

It's interesting to me that it's only the "Programming" tab that causes this issue. Everything else updates fine while connected. Hopefully this helps anyone else that makes the same mistake as I.

Edit: Just to answer your question, I was connected over ethernet to the RMC. I suspect there was some issue with the PLC trying to send the command which causes the RMC to fail the download.

I will let the software and tech support department know about this. Be ready to provide a copy of what didn't download to our tech support so we can duplicate this problem.


This is strange. Usually the problem has been with changing USB chips and drivers.

I'd be interested in what Delta has to say. In every startup we download programs while the PLC is attached. RMC75/150/200 without issue.

You don't perchance have the PLC and your PC set to the same IP address?

He has made contact with Delta's technical support. I too am interested. I haven't been told of any resolution yet.

Just sent everything off to Delta. I'll keep you posted on what they find.

I believe I found the reason this is occurring. In the code that my company uses (since before I showed up) the PLC watches for the Controller.Status.Run bit to become 0. When it does it immediately sends command 98 to put the RMC back into run mode.

When a download is performed for user programs in the RMC, it temporarily puts it into program mode, and switches back to run mode after finishing the download. It appears the PLC was racing it once it saw the program mode, causing the error to appear, and erasing any user programs that were already in the RMC!

Adding a delay to the command attempt solves this issue. I'm still a little confused by this as the code my company has used has seemingly worked perfectly fine on RMC150/151s, so this seems to be an issue that has only popped up on our switch to 200.

We found that the RMC75/150 guarded against this properly, but in the process of porting that code to the RMC200 when it was being developed, that guarding was lost. We have made a fix which will be included in our next firmware release, likely within a couple weeks.

-Jacob Paso

Perfect, thanks Jacob! Good to know I wasn't just going crazy.

I misspoke: this fix is an RMCTools software fix, not firmware.