ControlLogix Message Instruction to CompacLogix on different address

ebolbol

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Join Date
Apr 2011
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I'm trying to do a message instruction from ControlLogix you see on the left to the CompactLogix to the right. I'm losing this battle. I've tried a ton of different ways to type the path and still no go. Can one of you smart dudes look at the path I'm typing to see what I'm doing wrong? What complicates this is the two networks are on different addresses as shown in blue and red.

LOCAL_AREA_NETWORK, 2, 128.1.49.210, 1, 128.1.50.250 ,2 ,128.1.50.240 ,1 ,0

illustration.jpg
 
Almost there: the intermediate 1756 chassis' second module is being approached only via the backplane, so it gets a Slot number instead of an IP address.

LOCAL_AREA_NETWORK, 2, 128.1.49.210, 1, 6 ,2 ,128.1.50.240 ,1 ,0
 
You're welcome !

I worked for the Networks support group at RA a couple of years ago, so I've had a lot of practice with CIP paths.
 
Further explanation for anyone reading this thread...

CIP paths are always made up from pairs of specification values, viz...

Port, Destination, [Port, Destination], [Port Destination], and so on.

So a proper CIP path should consist of an even number of specifications, separated by commas - but read on....

To demonstrate, I will split up the OP's corrected path (courtesy Ken Roach) into its constituent parts.

LOCAL_AREA_NETWORK, 2, 128.1.49.210, 1, 6 ,2 ,128.1.50.240 ,1 ,0

LOCAL_AREA_NETWORK
This is already "defined" as 1,1 in the I/O config - Port = 1, the Backplane port : Destination = Slot 1, the local Ethernet module in the L55 chassis.
2, 128.1.49.210
Port = 2, the "Front" port (the RJ45 Ethernet port) : Destination = IP Address 128.1.49.210, the first Ethernet module in the L73 chassis.
1, 6
Port = 1, the Backplane port : Destination = Slot 6, the second Ethernet module in the L73 chassis.
2 ,128.1.50.240
Port = 2, the "Front" port (the RJ45 Ethernet port) : Destination = IP Address 128.1.50.240, the Ethernet address of the CompactLogix.
1 ,0
Port = 1, the Backplane port : Destination = Slot 0, the CompactLogix processor (always slot 0 for a CompactLogix).

You can see we have 9 parts to this path-spec, which is not an even number !

The start of the path could have been entered explicitly as ...

1,1, 2,128.1.49.210, 1, 6 ,2 ,128.1.50.240 ,1 ,0

But the system will automatically replace anything it "knows about" (from the I/O configuration), with the assigned name. In this case 1,1 is known in the I/O Config as LOCAL_AREA_NETWORK. This sort of hides the "pairing" specification from the unwary. A single "name" (an odd number) will replace an even number of path specification values.

I always teach students to construct CIP paths explicitly, and then they see the names appear as if by magic. Then when they have the idea firmly in their grasp, they can then use assigned I/O configuration names instead of a pair of CIP path specification values.
 
daba,

what an excellent... excellent thorough explanation! I copied this to have in my online notes. I experienced the But the system will automatically replace anything it "knows about" (from the I/O configuration), with the assigned name. first hand when I typed my path only to find out it had changed after exiting and going back.... but still worked so I left it alone. Initially I though maybe I mis-typed. At any rate, thank you for all the valuable info.
 
daba,

what an excellent... excellent thorough explanation! I copied this to have in my online notes. I experienced the But the system will automatically replace anything it "knows about" (from the I/O configuration), with the assigned name. first hand when I typed my path only to find out it had changed after exiting and going back.... but still worked so I left it alone. Initially I though maybe I mis-typed. At any rate, thank you for all the valuable info.

It gets better, as you enter the path in the Communications tab of the message configuration, the software will display if it is valid under the path entry box. View the attached pictures in sequence to see what I mean...

Path1.jpg Path2.jpg Path3.jpg
 
wait a minute... I don't remember seeing that... what version is that?:unsure: I know I have 19 but the controllers may be older versions.
 

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