Comm loss to processor

Good evening all. I have never had this happen before and I'm not sure what to make of it. I'm online with my 5/03 processor, fat, dumb and happy. Switch to remote program mode, still good. When I switch to run mode however I lose communications with my processor. Why is this?

What happens when you leave the key switch in the center position, and do the run/test etc in the software?

we need more information ... details please ...

you were "online" - through WHAT TYPE of connection? ... RS232? ... DH485? ...

is this the same SLC-5/03 system that you mentioned in an earlier thread? ... the one you were going to use for ASCII communications to a new "display" unit - over RS232? ...

DISCLAIMER: the following is sheer GUESSWORK ...

I'll assume (gosh I hate that word) that you were communicating online through the RS232 port - in the Program mode ...

I'll assume (I still hate that word) that you had just programmed in a new ASCII instruction - hoping to "transmit" out through the RS232 port ...

IF (big IF) those assumptions are correct, then when you went into the Run mode, MAYBE the new ASCII instruction suddenly started transmitting data out through the RS232 port ... if so, then that data transmission would certainly have interfered with your normal communications with RSLinx through the same RS232 port – knocking you offline ...

if all of that guesswork is correct, please let me know ... I'd like to run right out and buy a lottery ticket ...

on the other hand, if this is NOT your problem, then I'm afraid we'll need more information ...

I need to start waking up earlier. Ron beat me to it.
I have a idea that Ron is on the right track.
I did that same thing on a test unit last week. I hooked up to a 1100 with Ethernet and serial. Serial to capture string data and Ethernet to control the program over. I got in a hurry and pucked the wrong driver in linx. Downloaded the program not paying any attention to the warnings and lost comms.

we need more information ... details please ...

you were "online" - through WHAT TYPE of connection? ... RS232? ... DH485? ... RS232

is this the same SLC-5/03 system that you mentioned in an earlier thread? ... the one you were going to use for ASCII communications to a new "display" unit - over RS232? ... Yes

DISCLAIMER: the following is sheer GUESSWORK ...

I'll assume (gosh I hate that word) that you were communicating online through the RS232 port - in the Program mode ... Yes

I'll assume (I still hate that word) that you had just programmed in a new ASCII instruction - hoping to "transmit" out through the RS232 port ... Yes, and it was successful. I became so frustrated last night that I removed the processor and wiped-out the memory by unplugging the battery and shorting Vdd to Com as described by the Rockwell Software Technote.

IF (big IF) those assumptions are correct, then when you went into the Run mode, MAYBE the new ASCII instruction suddenly started transmitting data out through the RS232 port ... if so, then that data transmission would certainly have interfered with your normal communications with RSLinx through the same RS232 port – knocking you offline ... Ohhhh, I know how to check that. I'll just reconnect my null modem cable from the processor and reconnect it to the PC and use hyperterminal. Nothing should be there though, I have the blinking "FLT" LED telling me I have no program loaded. What happens after I tried to download a new project is, I went to RSLinx and did an auto-config. It sets my baud rate at 1200 (now this is after I have downloaded a new project) and it will stay online as long as I'm in program or remote program mode's. Switch it to Run and the RS-232 LED remains lit (does not blink), and I get a dialog box telling me that I've lost communication to the processor. I switch it back to the program mode or remote program mode and it begins to communicate.

if all of that guesswork is correct, please let me know ... I'd like to run right out and buy a lottery ticket ...

on the other hand, if this is NOT your problem, then I'm afraid we'll need more information ...

JeffKiper said:

I got in a hurry and pucked the wrong driver in linx. Downloaded the program not paying any attention to the warnings and lost comms.

Click to expand...

That was me last night. I was so excited I got the plc sending data to my laptop (using hyperlink) that when I saved my program it gave me that nasty tan colored screen that asks if I want to change my communication settings because they didn't match the other, and normally I have enough sense to select don't update but last night I selected to update it. It warned me that I would lose communications if I did it but it all happened so fast (that happens when I get excited learing new things). How does one recover from that?

ceilingwalker said:

That was me last night. I was so excited I got the plc sending data to my laptop (using hyperlink) that when I saved my program it gave me that nasty tan colored screen that asks if I want to change my communication settings because they didn't match the other, and normally I have enough sense to select don't update but last night I selected to update it. It warned me that I would lose communications if I did it but it all happened so fast (that happens when I get excited learing new things). How does one recover from that?

Click to expand...

First thing I would do is Correct the Comms in my Offline Program. If you go to one of your auto created backup programs you should be able to get back to the correct settings. Next wipe the program from the PLC's memory and load your corrected offline program. Does this PLC by any chance have another port on it?

Clay B. said:

First thing I would do is Correct the Comms in my Offline Program. If you go to one of your auto created backup programs you should be able to get back to the correct settings. Next wipe the program from the PLC's memory and load your corrected offline program. Does this PLC by any chance have another port on it?

Click to expand...

The challenge I have is that when I re-install my driver in Linx and then select auto-config, it automatically puts my baud rate at 1200, then says "auto-configuration Successful".

Well you do not have to use Auto Config. Just make note of the other settings and config it yourself. Not real sure why Auto Config would use such a low baud rate unless your cabling really sucked. Basically all Auto Config is doing is sending out a data burst and looking for what it gets back.

The only time I have ever had Auto Config "go stupid" was when I was using a cheapy brand serial to usb converter.

Ok, this is to help out someone else, should it happen to them. The mistake I made was selecting "apply" when it warned me of comm setting differences between what my project had versus what the processor had (correct me if I'm wrong). What I had to do was load my original project, make sure settings were the way I wanted them, in this case it was the 19.2k baud rate that was the issue. Then I downloaded the project making sure com1 baud was set to 19.2k. The nasty tan dialog box came up again and asked me if I wanted to apply changes. I told it yes to apply the changes. I then shut down my RSLogix 500 and opened the RSLinx. This time when I did the auto-config, it read the proper baud rate. Next I opened my project back up, went online, RS-232 LED was blinking at the proper rate and I could put it back in run mode and not lose communications. I'm back to being fat, dumb, and happy. Thanks all for your help.

When ever you have to connect to anything on an A/B serial port other than DF1, set a mental flag, to remind you there are extra "clicks in the middle at the end" because we all can get in a hurry and get ahead of windoze with our clicks and keystrokes. I have done it too. Two things that help:

1)Edit the first rung comment on LAD 2 rung zero and put the communication instructions there. Even if its got no other symbols or descriptions, and then Save the file, and upload all data tables. If there exists a rung comment tied to LAD 2:0, then just add the comms information at an approporiate spot. Include the IP address in this comment if applicable, even if the device is behind a Digi or NET-ENI, and commnet on both channels when applicable.

2) Set up a driver for different machines on multi-node capable networks, especially those that might have conflicting settings. It adds a step to switch drivers (because you have to stop some of them on DH485 or DH+) but it will serve as a method of saving all the comms settings you'll ever need, and this RSLinx set-up can be saved and ported to other programming devices easily.

ceilingwalker said:

The challenge I have is that when I re-install my driver in Linx and then select auto-config, it automatically puts my baud rate at 1200, then says "auto-configuration Successful".

Click to expand...

That 1200 baud default is a sign of really old firmware. Last one I recall doing that to me was before the turn of the century.

Paul

Now that I read the rest of the thread, I suggest you add an external means to programmatically switch modes on that channel. You can switch between System (DF1) and User (ASCII) with a system bit.

So you could send an ascii command and add a little logic to latch that bit (I would use a OTL for this if you want the mode change to survive subsequent power cycles), and have that bit as an interlock to your CH0 command logic.

If you can't send a command, you can wire a switch to a spare input to trigger the CH0 mode change logic. I am at home right now, so I can't look up the S2 bits.

Turn of the century that was when we used a string and a can between to devices.

JeffKiper said:

Turn of the century that was when we used a string and a can between to devices.

Click to expand...

The most robust, bulletproof communications setup I've seen so far!!
Easy to troubleshoot too.