Controllogix Redundancy Switchover

Two questions really:-
1. How do you force a redundancy switch-over from within the PLC code? I am struggling to find any information on this but believe it is possible.
2. This is related to the first question. For some reason when my secondary Ethernet module (talks to scada) is removed from the primary processor chassis switchover doesn't occur. This module is not currently connected to the scada and not sending or recieveing commands. Not sure if this makes a difference.

Setup. Each processor chassis consists of:-
1756-L71 processor (running on V24.52)
1756-RM2
1756-EN2TR (DLR)
1756-EN2TR (SCADA)

Any help would be much appropriated once again.

matt.smith said:

1. How do you force a redundancy switch-over from within the PLC code? I am struggling to find any information on this but believe it is possible.

Click to expand...

Read the manual ControlLogix Redundancy, page 147. You'll find how to configure a MSG instruction to do that.

matt.smith said:

Two questions really:-
2. This is related to the first question. For some reason when my secondary Ethernet module (talks to scada) is removed from the primary processor chassis switchover doesn't occur. This module is not currently connected to the scada and not sending or recieveing commands. Not sure if this makes a difference.

Setup. Each processor chassis consists of:-
1756-L71 processor (running on V24.52)
1756-RM2
1756-EN2TR (DLR)
1756-EN2TR (SCADA)

Click to expand...

Is the module declared on the project's I/O tree? I never tried a test like that.

nhatsen said:

Read the manual ControlLogix Redundancy, page 147. You'll find how to configure a MSG instruction to do that.

Click to expand...

When you come to set up the message and it asks for the redundancy module path you can't just set the path to '1' and as you can't see any of the redundancy chassis (apart from in linx) you can't add the redundancy module path. I can't see how this would work??

nhatsen said:

Is the module declared on the project's I/O tree? I never tried a test like that.

Click to expand...

yes it is (see attachment)
[3] 1756-EN2TR Ethernet_2_SCADA

There is a typo on page 147, Path should say: 1,<RM slot Number>

Example for RM in slot 3: 1,3

I don't think it is a typo error?

Contr_Conn said:

...Path should say: 1,<RM slot Number>...

Click to expand...

I think it does say that?...

1756-UM535_-EN-P said:

1 - the slot number of the 1756-RM, 1756-RM2,
1756-RMXT, or 1756-RM2XT module.

Click to expand...

It tells you to enter "1" for the backplane and then the slot number for the 1756-RMx module you are using.

So you end up with your example:

Example for RM in slot 3: 1,3

What they should have done in that table, in my opinion, is place a "," (comma) after the "1" instead of a "-" (hyphen) so as to more accurately reflect the correct syntax for a valid path...

1, the slot number of the 1756-RM, 1756-RM2,
1756-RMXT, or 1756-RM2XT module.

A small thing, but I don't think it's enough to cause confusion here?

matt.smith said:

...When you come to set up the message and it asks for the redundancy module path you can't just set the path to '1' and as you can't see any of the redundancy chassis...you can't add the redundancy module path. I can't see how this would work??...

Click to expand...

The path is to the 1756-RMx module that is local to the processor executing the MSG instruction. This could be the Primary or the Secondary 1756-RMx, depending in which way the switchover is being targeted. When executed, the switchover message is routed from the local 1756-RMx to the remote 1756-RM and they will behave as described on Page 148.

Regards,
George

1,2 worked
Thanks for your help

A small thing, but I don't think it's enough to cause confusion here?

Click to expand...

I have reported this and they will fix this in the next revision of the manual

"-" needs to be replaced with a comma

Good on you my friend. It is the smallest of details that count.

Among the minutiae I lurk.

Regards,
George

matt.smith said:

1,2 worked
Thanks for your help

Click to expand...

I know this thread is old. But asking out to know more about AB as my hardware is still in transit.

Created the MSG as per the manual and we control the switchover using the Source Element INT tag with a value of 1??

Can you guide on this part?
The MSG is always enabled and we control the switchover by changing the tag value to 1?

Cant find any examples for this.