Controller Dropping off Fiber Network

[Nick Anderson]

I'm running multiple controllers on a network that also utilizes fiber to travel long distances.  I ran into the problem today, where I have CAN King running, and watching the updates of all my controllers.  I then see that 2 of them drop off the network.  When I go to the controllers, I see that there is no BUS OFF (blinking red LED) error.  I try to cycle power on the fiber optic converter (copper to fiber), but that doesn't bring the controller back on to the network.  The only solution is cycling power on the controllers.

Has anybody else ran into an issue where a controller drops off the network but not because of CAN BUS related issue?

[Richard]

Hi Nick,

I have, the reason they went off line in my case was because the program stopped looping.  A power down and up would sort it usually but just for hours or several weeks at the most but eventually the controllers needed to be replaced.  It was discovered that by mistake I had been writing one particualr paramter to Eeprom a few times a second and it was burning it out prematurely.

Does the service tool still see the controller even though it's not sending and giving the red LED error?  In my case there was no red LED, just the geen power LED.  There service tool could see it and I could see that the loop time was odd (in different cases it was 65,000 or 0) and the loop count was not increasing.

However if yours are dropping out simultaneously in pairs it's not likely to be caused by eeproms.

Richard

[Nick Anderson]

Richard,

That sounds somewhat likewhat we're seeing.  When they go offline, we can still see them in the Service Tool.  The only difference I can think of is that I can still do something on a different controller (i.e. pressing a pushbutton), and I see it on the malfunctioning controller (via CAN message).  I can also see the program working, because it still performs the proper operations within the program (checked via checkpoints).  It just doesn't send any information out via CAN messaging.