Micro820 Noisy Environment Fault

James2724

Member
Join Date
Nov 2017
Location
Ohio
Posts
3
I have recently started using Allen-Bradley’s Micro820 PLC for simple machines that only have a couple dozen I/O and uncomplicated programming routines. On my very first system which used 5% of the user memory and very little ladder I would occasionally get fatal errors that I had to log on to clear. It was a fault code 0xF000 which is described as “The controller was reset due to a noisy environment or an internal hardware failure”. The odd thing was that this controller was set-up on my workbench with no possible interference in the area. The fault could be two days between occurrences. I replaced the controller, and the fault went away for good. That is until I sold three more units, now I am getting the same fault code on a different unit with no logical explanation. My only question is, is anyone else having “noisy environment” faults code 0xF000 with the Micro820 controller?
 
I have several of the Micro820's out in the field and they preform flawlessly, now with that being said, I too have encountered the same fault on more than 1 occasion and everytime - I have found that in one of my Timer routines I had a variable that could not be met.

Once I figured out that this was my problem I adjusted my ladder and never again would the plc fault.

I did just like you, replace controller and thought I had solved the problem but then it occurred again, that proved to me it had to be in the program.

So I set down, took my time and took a close look at my program, and in every sense it was an RTO function that I had setup and I was using this function in a NON productive manner.
 
The PT has to be reset before ET becomes larger. Other wise a Noise Error will occur.

I use this function to display RunTimes of different device I am controlling. Things that need some type of maintenance every so many hours. Works very well.
 
David,

Thanks for your previous responses. I looked at the programming and verified that I am only using TON timers. Is there anyway that you know of that the set-up of these timers can eventually cause a "Noisy Environment Error"? It seems odd that the configuration of a timer can compile, yet later (maybe a week) cause this fatal error completely shutting down the PLC control.

Thanks, Jim
 
I wish I could offer more, but I have only seen the RTO function block cause a "Noisy Environment Error".

I'm sure you will find the solution, just keep looking and asking!

This forum can be of great help.
 
I have recently started using Allen-Bradley’s Micro820 PLC for simple machines that only have a couple dozen I/O and uncomplicated programming routines. On my very first system which used 5% of the user memory and very little ladder I would occasionally get fatal errors that I had to log on to clear. It was a fault code 0xF000 which is described as “The controller was reset due to a noisy environment or an internal hardware failure”. The odd thing was that this controller was set-up on my workbench with no possible interference in the area. The fault could be two days between occurrences. I replaced the controller, and the fault went away for good. That is until I sold three more units, now I am getting the same fault code on a different unit with no logical explanation. My only question is, is anyone else having “noisy environment” faults code 0xF000 with the Micro820 controller?

I use RTO instructions, and I am getting controller faults (fault light on constantly), but when I log into the controller, there is no fault code. Thus, I cannot be sure if it is a noise error or not. Also, I use the RTO instruction quite a bit in the code to pulse a machine run minutes counter, so if this was the issue, I should be getting the error a whole lot more? Unless using the RTO makes the controller more susceptible to noise? Any thoughts guys?
 
I have also encountered the 0xF000 faults in the past but was not using RTO functions.

AB tech support was concerned that there was enough physical clearance around the PLC. (I think the manual specifies 2" all sides). I did increase the clearance as I had a DC power supply and ethernet switch within that spacing, but that made no improvement.
Also I had 2 identical panels beside each other, built the same time and only the one Micro820 encountered the fault.

Tech support also thought maybe the firmware became 'corrupted' so I ended up flashing to a newer firmware and the problem went away.

I did loose some confidence in the product line through all this.
 
After re-reading this post again, I want to add some more information that seems to be part of the problem.

I always try to make sure that all of my equipment(plc's) are on the latest firmware. Which I think is 10.01.

I also have from time to time had problems I can't solve - at this point I re-flash firmware and more than once that has fixed problem.
 
I re-flashed the firmware (rev 10.01 to 10.01) and then downloaded the program. The ever malfunctioning Micro820 has been running without a fault for about 48 hours now which is very encouraging since it would get the "Noisy environment" fault daily before the firmware re-flash. I will update my post if anything changes with this.
 
I re-flashed the firmware (rev 10.01 to 10.01) and then downloaded the program. The ever malfunctioning Micro820 has been running without a fault for about 48 hours now which is very encouraging since it would get the "Noisy environment" fault daily before the firmware re-flash. I will update my post if anything changes with this.

YES - Please be sure to keep us updated as to the out-come of this problem!

Thanks
 

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