DeviceNet communications

Hello,

a while back ago i posted a question about device net communications between an allen bradley PLC5 and a micro motion flow meter. I never went back to that post because i was severely under informed with device net and would have just wasted peoples time.

after diving into the subject more i now have a good grasp of whats going on but still have a question. I have a device net network where i have a flow meter on node 63 that sending data to the 1771-sdn modules input table. the PLC5 reads/writes the data with BTR/BTW instructions.

when i look at the scanner card properties, i see that its using a block transfer 62 to pull the data in from the flow meter. the data is 21 bytes long so the input setup tab shows a total of 168 bits being pulled in. what i dont see here is where the data is coming from.

i started to look at the micromotion flow meter in rsnetworxs and pulled out the EDS file and saw where the data is coming from. there is a group of data called input 6 that is 21 bytes long so i understand where 168 comes from.

now here is the issue, there is more data that i want to bring in that does not reside in input 6, there is another group input 7 that is also 21 bytes long that has the additional data.

how can i bring in two sets of input data into the scanner card so its accessible to my plc? i am writting this post away from my work computer so im trying to recall as much from memory after a long day so i can clarify any questions that arise.

thanks
Ricardo L.

Can you post a link to a user manual for the MicroMotion, or its EDS file ?

Unfortunately you have probably identified a situation where you can select a particular "assembly" of data to be part of the I/O connection, and in general you can't connect to more than one Assembly at a time.

The other technique for reading data that's packed into an Assembly is to send an "explicit message" to the device. That's a non-trivial task with the old 1771-SDN, but it's possible.

Hello Ken,

thanks for your reply. I have attached the EDS file and also a screenshot of the parameters for the flow meter and scanner on rsnetworx. Looking at the parameters, i see that parameter #7 is the one that is setting the group of variables to make available for the scanner.

In the meter's parameter tab, there exists poll info and cyclic info where it appears i can select a set of input data for each one. i also see the same terms in the scanners scanlist tab when selecting the edit I/O parameters of the flow meter and currently only the polled option is selected. In RSnetworx, If i were to set the cyclic info parameter for the meter to reflect the second set of data that i need, could i select the cyclic box in that scanner parameter tab and map both sets of data?