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Andrew Grimm

EIP Class 1 Connection Data Structure

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I am needing some guidance on an application I'm working on. I'm trying to obtain data from a profinet slave device to an Allen Bradley compactlogix PLC. I am using a Prosoft PLX82-EIP-PNC profinet-/ethernet-ip gateway as a median to allow me to access the profinet data. In RSlogix5000, I have created an EIP Class 1 connection for the profinet controller and AB PLC (248 words of input data, 248 words of output data). The same structure is created in the profinet controller (248 words of input data, 248 words of output data). The profinet gateway and PLC are communicating properly.

From my profinet slave device, I have a specification that the data is structured within a 23 byte format. Connecting to my profinet gateway, I can see this data. I have attached an image that shows the specification of the profinet data and the data values displayed inside the profinet controller.

From the PLC side, I'm needing to be able to see this data and put it in meaningful values. I am using the profinet slave device's internal temperature as an example to work towards.

I'm not sure the best way to be able to handle this data and structure it to a meaningful value inside the PLC. (I am using the device's internal temperature as an example to try and get into the PLC).

 

Thanks,

CIP Connection.JPG

profinet_gateway_data.JPG

Slave_data_structure.JPG

rslogix tags.JPG

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Not sure if this helps and not knowing the bridge device you are using, but Siemens and Allen-Bradley have the opposite ordering of bytes (Big Endian vs. Little Endian).  You might need to write a couple of rungs in the CompactLogix to swap bytes to get a realistic value.  Then again, maybe the gateway was expected to do that already.

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Which ordering of bytes is Allen Bradley using? My gateway is configured as no byte swap so it should pass the data onto AB the same as its received. The specification from the Profinet slave device is Big Endian/Motorola)

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I found a solution. The gateway I am using is supposed to have the capability to swap bytes. I tried to set this directly in the gateway and it wasn't working.

 

I ended up using a few BTD instructions to re structure the values and now its working correctly.

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