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Old January 13th, 2022, 03:48 PM   #1
MikeVT
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Ethernet Messaging to and from Control Logix and Micro Logix 1400

I am trying to exchange data (N registers) to and from a Control Logix PLC. I am programming the messages in the Control Logix program, to retrieve, a send data. I seem to have the path correct, in the Control Logix PLC, but I cannot see the data (heartbeat) from the Micro Logix PLC. The Control Logix PLC is running firmware 20.19, if that's important.



I am looking to retrive data from N7:18, to the Control Logix PLC.


I am looking to send data from the Control Logix PLC to N7:17, in the Micro Logix PLC


Any hints or pointers, or gotcha's to look out for?
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Old January 13th, 2022, 04:08 PM   #2
IanM8040
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Quote:
Originally Posted by MikeVT View Post
I am trying to exchange data (N registers) to and from a Control Logix PLC. I am programming the messages in the Control Logix program, to retrieve, a send data. I seem to have the path correct, in the Control Logix PLC, but I cannot see the data (heartbeat) from the Micro Logix PLC. The Control Logix PLC is running firmware 20.19, if that's important.



I am looking to retrive data from N7:18, to the Control Logix PLC.


I am looking to send data from the Control Logix PLC to N7:17, in the Micro Logix PLC


Any hints or pointers, or gotcha's to look out for?
What does your message instruction look like? It won't be a simple IP only, such as the path would look like - 1,en2t_slot_number,2,MicroIP -

Are you sure both devices are on the network? Can you ping them, and there's no conflicts?

Last edited by IanM8040; January 13th, 2022 at 04:10 PM. Reason: Bad Grammar
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Old January 13th, 2022, 04:19 PM   #3
MikeVT
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I am sure both devices are on the network, and reachable.


The message path is; 1.7,1,192.168.202.120 That is the IP address of the ML1400.




That path should have read: 1,7,1,192.168.202.120
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Old January 13th, 2022, 04:25 PM   #4
Ken Roach
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This should be fairly straightforward.

The ControlLogix supports SLC/MicroLogix style Data Table Typed Read and Data Table Typed Write instructions, and as you have seen while configuring the MSG instruction you can address the MicroLogix data table elements directly. There's no need for the "PLC/SLC Mapping" feature in the ControlLogix.

Examine the logic for the MSG instructions to be sure that the preceding rung conditions are going from false to true every time you want to execute the MSG. I like to use a repeating timer whose /DN bit triggers the MSG in order to manage the frequency of the reads and writes, and also use an XIO with the /EN bit to be sure that I don't fill the comms buffers up during a timeout in the event the target is disconnected or powered down.

To be 100% sure you have the CIP Path and Data Table Address correct, simplify your logic to a test BOOL tag and an XIC, and manually toggle that tag to execute the MSG instruction just once, so you can examine the /DN bit and any .ER or .EXERR values that result.
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Old January 13th, 2022, 04:27 PM   #5
Ken Roach
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If your Ethernet module is in Slot 7 of the ControlLogix chassis, then you need to follow that CIP "hop" with the Ethernet network port number, which is "2". In CIP syntax, Port 1 is always the ControlLogix backplane.

1,7,2,192.168.202.120
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Old January 13th, 2022, 04:31 PM   #6
MikeVT
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Found it! Feel really foolish. E-net card was is=n slot 6. We were trying to address slot 7.


DUH!!!!
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Old January 13th, 2022, 04:40 PM   #7
Ken Roach
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Raise your hand if you've never mis-counted a Logix slot number.

(looks around)

Thanks for the update and followup. Happy messaging !
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Old January 13th, 2022, 07:08 PM   #8
TheWaterboy
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Zero based addressing . . .
Now lets talk modbus addressing !
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