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jpmaher

Allen Bradley 1794-ADN

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I have a 1794-ADN module that no longer wants to play the game. I tried to download a new configuration to it while it was still in the scanners scan table and ever since that as soon as I power up the ADN on the network it causes a "bus off" condition. Does anyone know of a way to reset this module to factory to try and get it to go again? Thanks. Joe Maher.

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From Rockwells Technotes HERE Edited by TechJunki

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Hi thanks for the info. But the only problem is I cant see it on the network as it causes the network to fail as soon as it is turned on. Is there a way of clearing the flash memory to factory via the hardware some how? Thanks.

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Have you singled out the module.. (removed all other modules on the rail)?? You may also want to try reseating the modules and checking the pins to the backplane (bend or bad pins). These module are notorious for having bad pin connections. --in my past experiences anyway-- Edited by TechJunki

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Hi. At this point I have disconnected all Flex IO from teh adaptor and then connect it into a working network (via a drop cable that is already on the network) which then causes the network to fail. I assume that the ADN maybe spitting out Bad data. Though I'm sure it is only doing it because something got scrambled during the last config change which it was working perfectly before hand. Thanks.

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jp, have you tried to connect to the device with your laptop while seperated from the rest of the network? Could it be that when you last downloaded a configuration to it that it's node address changed and is now conflicting with the other devices on the network? I use a 1771-KFD RS232 module to download to a device while on the bench. Then hook it the the rest of the network. This may not work in your case. But won't hurt to try. Check that the baud rate & node address are correct before downloading the configuration. Good Luck BD

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Hi Biker. I also have a 1770-KFD which I have tried hooking it upto with no luck. It causes the old Network status light to start flashing red. The hardware address for the ADN's are set via thumbwheels on the front. Thanks.

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About the only thing that can cause bus-off when the hardware is sound is a mismatch between hard-set baud rates. Try initializing the KFD driver at all three (125, 250, 500 kb/s) data rates. It does sound like the module has somehow gotten into a mode where the CAN transciever isn't working right. I've never heard of that happening from a firmware problem.

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Don't forget to restart, or unplug and plug back in your KFD module after changing baud rates. I seemed to remember you should cycle power on your device for baud rates to take effect...

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I had this exact same thing happen to me about a week ago. I removed the ADN from the scan list. Then I disconnected the DeviceNet plug, recycled module supply power, reset the node address, and reconnected the DeviceNet plug....in that order. Then I added it back to the scan list and was up and running with no problems. Also, I was using 125kb or autobaud on everything on my network. $ Edited by Money4Nothing

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Hi Money4nothing Unfortunately I have tried this one a few times already with no luck. At the moment on the network I'm currently trying it on I have 3 ADN's and one 1770-KFD connected.RSnetworx can see the other ADN's (Nodes 2 & 3) no problems but the ADN at node 4 can not be seen.I manually entered the Node 4 ADN into the table on RSnetworx so I could try and get the Class instance editor up for it but each time I try the class instance editor comes up with the following error. ("Error opening connection to this device. Error code = 0x80070057. Online operations will not be possible for this device. Please make sure that the device is connected to the network and try again.") One thing I noticed was that the only light up on the offending ADN is the power light all other lights are off. This is the same if connected to the network or not. Though when you first power up the device all lights seem to go through a normal start-up sequence. I can also confirm that the network cabling is fine as other devices work off the same cable that is plugged in to the offending ADN. The module seems to have had its config scrambled and is no longer allowing comms to or from it. Is there a hardware way of resetting it or is it a back to factory to get it restored? Is there any way possible that I can could possibly do it? Thanks everyone. Edited by jpmaher

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If your I/O status and Mod/Net status LEDs are not on, then you have a problem with your connection to the network. Check the voltage of the device net power at the module. Make sure the polarity and level are right. Make sure your CAN lines are not crossed. You may have a problem in your tap or drop. Check the connections very carefully. If all that checks out, you probably have a faulty module, and you'll need to replace it or get tech support form Allen Bradley. Try to swap that module with another one in your network, and see if you can connect. $ Edited by Money4Nothing

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