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Old February 21st, 2013, 07:03 AM   #1
RasPLC01
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Pencil Control logix Redundancy issue

Dear members

I am building a redundant Control logix system with following

Chassis contains following for both primary and secondary

SLOT 0:1756-L73
SLOT1: 1756-RM /B
SLOT 2: 1756-EN2TR /B
SLOT 3 : EMPTY
SLOT 4: 1756-CN2R /B
SLOT 5: EMPTY
SLOT 6: EN2T / C

i have 3 1794-ACNR15 adapter connected to Controlnet module for FLEX I/O

My issue is the redundancy can not be achieved , RM module on Secondary shows DISQ ( disqualified) , but primary is fine Shows PRIM

I have Done already following

1) I have All firm ware has been updated as shown in attachment (both chassis same )
2) Controlnet module address keep same ( assigned 90, 91 automatically by processor , ACNR15 Modules address is 55, 66, 88 lower than keeper as usual)
3) Ethernet IP module's ip address keep as same ( assigned next higher by controller )
4) Upload a small program in primary chassis with redundancy enabled

Then i had connected to RSlinx and access RMCT , i start to sync through the tab . i got the error as per attachment

what should i do next ? how can i go to online with secondary same time?


Any help would be highly appreciated

Please find the attachment
Attached Images
File Type: jpg Untitled.jpg (51.1 KB, 30 views)
File Type: jpg firmware.jpg (59.4 KB, 20 views)
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Old February 21st, 2013, 07:58 AM   #2
dmargineau
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Logix5000 Enhanced Redundancy is a pretty substatial endeavour...
I believe the firmware level of your 1756-RM module should match the controller's major level one; the (inverted) pic states that the 1756-RM within the Primary chassis is at level 3.3; it should be updated to 20.xy.
Generalizing, all of the enhanced redundancy system's components have to carry a minimum of firmware revision level depending of the involved CPUs one.

User Manual at : http://literature.rockwellautomation...m535_-en-p.pdf

Enhanced Redundancy Rev.20.054 Kit at:

http://compatibility.rockwellautomat...versions=50471
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Old February 21st, 2013, 10:40 AM   #3
Ken Roach
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The 1756-EN2TR module firmware might not be correct.

According to RA Knowledgebase Article ID 19232, the required firmware versions for ControlLogix Enhanced Redundancy release 20.054 are:

1756-L73 Required: 20.054 Yours: 20.54
1756-RM/B Required: 3.03 Yours: 3.03
1756-EN2TR Required: 5.08 Yours: 5.28
1756-CN2R/B Required: 20.020 Yours: 20.20
1756-EN2T Required: 5.08 Yours: 5.08

This information is also in the Release Notes (TechConnect not required):

http://literature.rockwellautomation...n694_-en-p.pdf

The 1756-RM tool should give you additional details about which module is causing the failure to synchronize.

Do you have the fiber optic cable connected securely between the two 1756-RM modules ?
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Old February 21st, 2013, 10:42 AM   #4
Ken Roach
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ControlLogix Redundancy is treated as a single CPU; you cannot "go online with the secondary" separately from the main controller.

The Event Log of the 1756-RM module is going to tell you more about how the system is trying to syncrhonize.

And let's take a step way back: do you have the "Use Redundancy" checkbox checked in RSLogix 5000 ?
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Old February 21st, 2013, 11:41 AM   #5
RasPLC01
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Thanks for the reply

Let me check the EN2TR FW updation and Event log in RMCT

Yes Ken , FO Cable is properly installed and Redundancy in RSLOGIX5000 is checked

I Think we need to download Logic to only Primary , then it will syn to Secondary also Am i rt?
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Old February 21st, 2013, 11:45 AM   #6
Ken Roach
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You're correct: the 1756-RM automatically cross-loads the user program (and edits, when you make them) from the Primary to the Secondary controller. It can take a few minutes, but in general it's an automatic function.

I'm not a Redundancy expert, but the last time I used one the thing that surprised me is that the Ethernet modules need to be able to communicate with one another over the TCP/IP network as well as over the backplane/SRM link. Some folks assume (as I did) that you could connect them to totally separate Ethernet networks.
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Old February 21st, 2013, 11:46 AM   #7
RasPLC01
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Ken,

Use Redundancy check box is you are talking about is the one we found at starting of a new program right?
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Old February 21st, 2013, 12:02 PM   #8
Ken Roach
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That's correct; it's in the Controller Properties section of RSLogix 5000, in the Redundancy Tab.
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Old February 21st, 2013, 01:15 PM   #9
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I am pretty sure you need at least one more if not two more keeper capable devices. (CN2R's). I do not think the Flex adapters count.

I am not sure that this is keeping you from synching, but I do think you have a configuration issue.

I would look it up and be sure.

RSL
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Old February 21st, 2013, 01:21 PM   #10
Ken Roach
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The function you need to keep alive during Redundancy switchover is the ControlNet "Moderator", rather than the Keeper. The 1794-ACNR's perform this function fine.

Without a Keeper, he won't be able to add another device to the ControlNet schedule or bring one back from being offline until the ControlLogix is reconnected, but since it's the sole controller in the system that doesn't matter.

I do recommend not using high ControlNet node numbers just so they are more human-readable. Use 1,2,3,4,5 instead of 44, 55, 66, 77. Having large gaps in the ControlNet node numbers just slows down the token rotation and makes browsing and other unscheduled network communications slower.l
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Old February 21st, 2013, 01:23 PM   #11
RSL
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Thanks Ken,

It's been a while, you are right Moderator. I was thinking you had to have 4 nodes and the sequence of the numbers mattered?

Is that right?
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Old February 21st, 2013, 01:34 PM   #12
Ken Roach
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Adult supervision required

A working ControlNet needs only two nodes, but a working ControlLogix Redundancy system needs four.

When the Primary and Secondary controllers switch roles, the 1756-CNBR modules switch node numbers.

But they have to momentarily (and it's really just a few milliseconds) disconnect from the network to do so; at a low level, a ControlNet device can't change its node number while actively participating in the network. If there were only one additional device on the network, it would go into "lonely" mode when it suddenly couldn't hear transmissions from any other device.

So that's why a Redundant system needs at least two nodes in addition to the 1756-CNBR/CN2R modules in the controller chassis. Those two nodes can still "hear" one another on the wire during that instant when the two Redundancy bridges are disconnecting and reconnecting to the network.

The fact that the controller-resident 1756-CNBRs need to be at higher node numbers than the I/O devices is because of the way the Moderator token passes... I'm not sure of the exact mechanism but you're correct in the fact that the controller node numbers should be higher than the I/O device node numbers.

Any ControlNet device, scheduled or unscheduled, can be a Moderator and keep a Redundancy system happy. I used to do demos with a Redundant chassis pair, one FLEX I/O adapter, and my 1784-PCC card to keep the network up during switchover.
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Old February 21st, 2013, 01:49 PM   #13
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Yes, I meant redundancy needs 4. In the dark recess of my mind I remembered that. The goes lonely piece I recall too now that you remind me.

You are a wealth of knowledge, thanks.

RSL
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Old February 22nd, 2013, 05:53 AM   #14
RasPLC01
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Ken
I check the the event log found that error is by EN2T module
i just connect the CAT cable ( it was disconnected ) then SYN done perfectly

Thanks
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Old February 22nd, 2013, 02:03 PM   #15
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That makes sense about the EN2T needing a connection. I do not think it is using this connection to synchronize. It is however monitoring all the network connections in both racks. If you lose one in the Primary you will get a failover. If you lose one in the secondary you will get disqualified secondary.

Basically the system needs to know that the secondary rack is "fully qualified" as a secondary. If it is missing a network connection then it deems that rack to be in bad health and takes action.

This makes sense to me.

RSL
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