You are not registered yet. Please click here to register!


 
 
plc storereviewsdownloads
This board is for PLC Related Q&A ONLY. Please DON'T use it for advertising, etc.
 
Try our online PLC Simulator- FREE.  Click here now to try it.

New Here? Please read this important info!!!


Go Back   PLCS.net - Interactive Q & A > PLCS.net - Interactive Q & A > LIVE PLC Questions And Answers

Reply
 
Thread Tools Display Modes
Old January 13th, 2022, 01:12 PM   #1
TheWaterboy
Lifetime Supporting Member + Moderator
United States

TheWaterboy is offline
 
TheWaterboy's Avatar
 
Join Date: May 2006
Location: State of Denial
Posts: 1,275
Logix v33 - Stuck MSG .EN bit

Anyone seen a logix v32 or v33 get a stuck EN bit on a MSG? (also an L61 v20 oddly enough)

I can put an AFI in front of it and still can't get the .EN to clear.
I got into the MGS tag itself and I can clear the .EN but not the .ST, it sets right back to true.
I replace the MSG in logic with a new one with et same UDT and that one does the same thing.
The original MSG that is now unused but still has the ST bit set and will still not allow me to clear it in the tag editor.

The MSG uses a UDT (BOOL[64] BOOL[64]DINT[64]) that has been working fine for many months, yet now seems to be the reason this occurs.

This started when I stored the recipient PLC's program to EEProm which I have done several dozen times before yesterday. This obviously would have caused the MSG to fail but also has created this condition.

RA Support found a note that said this happens when the remote comms are interrupted which is likely to be what happened but said it was fixed in v33.
I updated to v33 and the problem remains. As a test I created a similar MSG in an L61 and that does the same thing! Again these have been working fine for months on V32

Additionally I can't edit the existing MSG since the ST bit is set and the PLC thinks its in a active state, so I have to create a new MSG to try new things leaving dead MSG tags in the DB with bits I can't clear.

I created one to read DINTs from the same endpoint and that works fine. But I have 3 MSG's tags in the tag list that have the ST bit set.

To make this worse... Since the PLC considers the MSG active, I can't change the PLC state from Run to Program... at all. I have to cycle power to regain control.

And how is YOUR day going?

.
  Reply With Quote
Old January 13th, 2022, 01:38 PM   #2
drbitboy
Lifetime Supporting Member
United States

drbitboy is offline
 
drbitboy's Avatar
 
Join Date: Dec 2019
Location: Rochester, NY
Posts: 4,174
Quote:
Originally Posted by TheWaterboy View Post
[tale of woe ...] And how is YOUR day going?
Hahaha. Better than that.

Look at it this way: this is how people become experts on topics - like MSGs.
__________________
i) Take care of the bits, and the bytes will take care of themselves.
ii) There is no software problem that cannot be solved with another layer of indirection.
iii) I solemnly swear that I am up to no good
  Reply With Quote
Old January 13th, 2022, 01:43 PM   #3
drbitboy
Lifetime Supporting Member
United States

drbitboy is offline
 
drbitboy's Avatar
 
Join Date: Dec 2019
Location: Rochester, NY
Posts: 4,174
Quote:
Originally Posted by TheWaterboy View Post
Since the PLC considers the MSG active, I can't change the PLC state from Run to Program... at all. I have to cycle power to regain control.

And how is YOUR day going?

. <===!

It's the "at all" and the final full-stop that make it art .
__________________
i) Take care of the bits, and the bytes will take care of themselves.
ii) There is no software problem that cannot be solved with another layer of indirection.
iii) I solemnly swear that I am up to no good
  Reply With Quote
Old January 13th, 2022, 01:47 PM   #4
TheWaterboy
Lifetime Supporting Member + Moderator
United States

TheWaterboy is offline
 
TheWaterboy's Avatar
 
Join Date: May 2006
Location: State of Denial
Posts: 1,275
Yea, the full stop is just because the forum formats the last line right at the bottom and I wanted to create some space

... much like those around me right now as I am swearing at my screen. :P
.
  Reply With Quote
Old January 13th, 2022, 01:53 PM   #5
drbitboy
Lifetime Supporting Member
United States

drbitboy is offline
 
drbitboy's Avatar
 
Join Date: Dec 2019
Location: Rochester, NY
Posts: 4,174
What is the state of the .EW bit?
.
__________________
i) Take care of the bits, and the bytes will take care of themselves.
ii) There is no software problem that cannot be solved with another layer of indirection.
iii) I solemnly swear that I am up to no good
  Reply With Quote
Old January 13th, 2022, 01:58 PM   #6
TheWaterboy
Lifetime Supporting Member + Moderator
United States

TheWaterboy is offline
 
TheWaterboy's Avatar
 
Join Date: May 2006
Location: State of Denial
Posts: 1,275
EW is not set ever. Only one or maybe 2 MSG at a time ever occur as I wait till one finished before the next starts so the Queue is never full .

normally I set the . TO bit after 5 seconds since that's all that is needed but that now has no effect either. The thing doesn't let go even after the default 30 seconds, or even 1 hour.
  Reply With Quote
Old January 13th, 2022, 01:59 PM   #7
plvlce
Lifetime Supporting Member
United States

plvlce is offline
 
Join Date: May 2017
Location: Michigan
Posts: 395
Quote:
Originally Posted by TheWaterboy View Post
The original MSG that is now unused but still has the ST bit set and will still not allow me to clear it in the tag editor.
FWIW some years ago I had a bit in a motion instruction that I needed to clear but tag editor would not let me; iirc I directly addressed it with an unconditional OTU to do so.

EDIT: The instruction help for MSG says "Do not change the ST bit. The controller ignores the change and uses the internally-stored value of the bit."

Last edited by plvlce; January 13th, 2022 at 02:03 PM.
  Reply With Quote
Old January 13th, 2022, 02:07 PM   #8
TheWaterboy
Lifetime Supporting Member + Moderator
United States

TheWaterboy is offline
 
TheWaterboy's Avatar
 
Join Date: May 2006
Location: State of Denial
Posts: 1,275
I know I should not touch that bit and I normally wouldn't, it's just a symptom of the larger problem.

That bit being being set prevents the PLC from changing state or the MSG from being edited even when the MSG is not in logic and only exists as a tag.
  Reply With Quote
Old January 13th, 2022, 05:00 PM   #9
Jim3846
Member
United States

Jim3846 is offline
 
Join Date: Dec 2019
Location: Cincinnati OH
Posts: 273
I had problems like that when trying to edit the MSG block. I always used an AFI to disable rung and this always let me edit the MSG block.

This happened during Dec 2021.
Version 32 problem with MSG
I did have an issue on MSG read where I could not get the contrologix vers 32 processor to read a SLC505. But could do a MSG write from the contrologix vers 32 processor to the SLC505. But when I looked at another processor that was at version 20 it could read and write the SLC505. I looked at memory, connections, blah, blah, etc.... Frustrating, but turned out I did not need the MSG read, so did not have to do a write MSG in the SLC505.

I feel you pain!
  Reply With Quote
Old January 13th, 2022, 05:01 PM   #10
TheWaterboy
Lifetime Supporting Member + Moderator
United States

TheWaterboy is offline
 
TheWaterboy's Avatar
 
Join Date: May 2006
Location: State of Denial
Posts: 1,275
Well... I find that I can make identical MSG transfers to anywhere except that one PLC.

OK fine, that PLC has some problem I need to find....but . . .

How is it possible for a remote PLC to hold this MSG enabled like it is?
  Reply With Quote
Old January 13th, 2022, 06:30 PM   #11
TheWaterboy
Lifetime Supporting Member + Moderator
United States

TheWaterboy is offline
 
TheWaterboy's Avatar
 
Join Date: May 2006
Location: State of Denial
Posts: 1,275
Cant save the file Error is "CIP Error: Address out of Range"

I also find that I can't directly change tag values within the UDT on the remote end. Error is "Failed to modify the tag value Address out of Range"

This Thread had a similar issue so I tried the same thing and it worked. Downloaded the program into the PLC again and this corrected it.

So a corrupted File with no evidence of corruption.
  Reply With Quote
Old January 13th, 2022, 07:05 PM   #12
TheWaterboy
Lifetime Supporting Member + Moderator
United States

TheWaterboy is offline
 
TheWaterboy's Avatar
 
Join Date: May 2006
Location: State of Denial
Posts: 1,275
It's still a big concern that the corruption of a remote site can hold the polling master hostage like this. No one at RS Support can explain it.

Looks like a good attack vector should someone be able to reproduce it at will.
  Reply With Quote
Reply
Jump to Live PLC Question and Answer Forum

Bookmarks


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Topics
Thread Thread Starter Forum Replies Last Post
compact logix l18 and control logix l63 msg instruction Rahul Kumbhar LIVE PLC Questions And Answers 6 February 28th, 2018 12:53 AM
RSLogix 5000 bit stuck. Elcan LIVE PLC Questions And Answers 37 March 20th, 2017 10:46 PM
MSG - Compact Logix to Micro1200 via ENI pembry LIVE PLC Questions And Answers 18 January 7th, 2017 12:22 PM
Fanuc 90/30 HMI programming CalG LIVE PLC Questions And Answers 128 February 27th, 2013 02:11 AM
PID in Control logix get stuck jainil2210 LIVE PLC Questions And Answers 2 March 7th, 2012 07:50 AM


All times are GMT -4. The time now is 03:12 PM.


.