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.

---------->>>>>Get FREE PLC Programming Tips

New Here? Please read this important info!!!


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

PLC training tools sale

Reply
Thread Tools Display Modes
Unread November 7th, 2019, 04:38 PM   #1
RonJohn
Lifetime Supporting Member
United States

RonJohn is offline
 
RonJohn's Avatar
 
Join Date: Jul 2013
Location: NE Ohio
Posts: 489
1756 Digital I/O modules v2.x

I was going through our spare parts to put together a 1756 rack of I/O to replace an old 1771 rack. About 5-6 of my spare digital cards are firmware V2.x. I understand from TechConnect ID494609 that because of ASIC differences, V2.x firmware cannot be flashed up to v3.x and vice versa.

That said, is there any issue with reusing these v2.x cards in my rack? My main concern is having to change the module definition if one of these cards ever breaks because it's a bear to take this system offline to download the program.

Thanks in advance.
  Reply With Quote
Unread November 7th, 2019, 04:44 PM   #2
rupej
Member
United States

rupej is offline
 
Join Date: Sep 2014
Location: NC
Posts: 647
If you disable keying, or perhaps even set keying to "compatible module", it won't matter what revision you put in, right?
  Reply With Quote
Unread November 7th, 2019, 05:22 PM   #3
RonJohn
Lifetime Supporting Member
United States

RonJohn is offline
 
RonJohn's Avatar
 
Join Date: Jul 2013
Location: NE Ohio
Posts: 489
Quote:
Originally Posted by rupej View Post
If you disable keying, or perhaps even set keying to "compatible module", it won't matter what revision you put in, right?
I'm pretty certain "Compatible Module" only allows for minor revision differences, not major rev., so that's out.

We could disable keying but that leaves us susceptible to Bubba. Haven't gone down that road before.

Also wasn't sure if there were quality issues with v2.x cards...
  Reply With Quote
Unread November 7th, 2019, 07:51 PM   #4
rupej
Member
United States

rupej is offline
 
Join Date: Sep 2014
Location: NC
Posts: 647
I could be wrong, but I always thought "disable keying" is still a keying of some sort. You can't plug an output card into a slot where there was an input and cause any more mayhem than just leaving it unplugged. The tree will still flag a compatibility issue.
  Reply With Quote
Unread November 7th, 2019, 08:15 PM   #5
Maxkling
Member
United States

Maxkling is offline
 
Join Date: Mar 2011
Location: Atlanta
Posts: 268
I think with disable keying the data size and type still must match, if not it will still reject the module.

Also compatible keying should allow higher revisions to be accepted.
  Reply With Quote
Unread November 8th, 2019, 09:54 AM   #6
Operaghost
Member
United States

Operaghost is offline
 
Operaghost's Avatar
 
Join Date: Apr 2002
Location: Dallas, TX USA
Posts: 2,657
Compatible Module keying allows for any revision that is the same as, or newer, as defined in the General tab. That includes major revisions.

Using compatible keying and then defining a module as Rev 2.x will allow a replacement module to be Rev 3.xx or newer. The thinking being that you are likely to have an older module being replaced by a newer module and you want to be able to do that without any fuss.

Be aware though, that this setting forces the newer module to operate as if it were the older revision. What that means is that if there were any new features in Rev 3, those features would not be available.

If the module was defined as Rev 3.xx but the actual module was Rev 2.xx then the only option would be to disable keying. And yes, the "type" of module must match or else it will reject the module. An output for an input will fail.

Years ago I was working on a system that had been developed using some DC inputs and outputs. I was using the same system but using AC I/O and devices instead. The program I was given was for the DC system. I went in and disabled the keying since I was using the AC equivalent modules (IA16 versus IB16). The ControlLogix system was just fine with this. No errors whatsoever. But oddly, some of the AC input tags were flickering on and off on their own. I chalked it up to possibly a difference in the tag structure, possibly of the Configuration data. Once I had nailed down the reason for the problem, I just redefined the modules rather than investigate further.

OG

Last edited by Operaghost; November 8th, 2019 at 10:04 AM.
  Reply With Quote
Unread November 8th, 2019, 10:49 AM   #7
RonJohn
Lifetime Supporting Member
United States

RonJohn is offline
 
RonJohn's Avatar
 
Join Date: Jul 2013
Location: NE Ohio
Posts: 489
Folks, thanks so much for the feedback. I learned something new (to me) so that is always a good thing!

I came across the 1756-rn632_-en-p Digital I/O Release Notes which confirms what all of you said above. Looks like I'm good to go with compatible keying.

Onward & upward!
  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
How to remove node module and its I/O modules out from Logix5000 properly? wendaiyu LIVE PLC Questions And Answers 1 March 22nd, 2016 05:52 PM
Beckhoff adding I/O modules bennyk@37.com LIVE PLC Questions And Answers 11 November 15th, 2013 09:00 AM
Using program on chassis with inhibited modules in I/O list alfman96 LIVE PLC Questions And Answers 4 October 9th, 2013 01:50 AM
S7-200 digital expansion modules nightex LIVE PLC Questions And Answers 1 February 15th, 2011 01:52 PM
ASI I/O modules ProDave LIVE PLC Questions And Answers 0 August 9th, 2002 09:30 AM


All times are GMT -5. The time now is 06:09 PM.


.