OPC/Variable Frequency Drives

einstein_g · Sep 4, 2018

I need to collect data (yet to be specified, but voltage etc) from a bunch of VFDs (Powerflex 753) connected to Allen Bradley (ControlLogix) PLCs.

I'm using Kepware to communicate with the PLCs. I have no idea how VFDs are typically networked with PLCs.

Anyone with a clue on what the recommended way of getting this data would be? I mean, should I access the VFDs directly from Kepware, or does Kepware talk to the PLC, which in turn talks to the VFD?

RonJohn · Sep 4, 2018

I'm not up to date on using Kepware so take this for what it's worth...

I'd think you'd want to grab the data from the PLC, if possible. I wouldn't want anything talking to my IO devices except for my processor.

There are numerous ways the Logix could be communicating with the PowerFlex - digital/analog wired I/O, Remote I/O, Ethernet I/P, ControlNet, etc. Find out what protocol is being used, first off.

Secondly, once you find out what parameters you need to monitor for data collection, set up DataLinks in the drive so that this drive data can be read directly into the Logix. Up to 16 DataLinks can be read from a PF753 to a Logix processor.

If your communication protocol doesn't support DataLinks, then things may have just gotten a bit more complicated.

mdim · Sep 4, 2018

Scattered message is also an option, if it is not affecting the control comms over datalinks. There are some topics even here in the forum for 700 and 755.
Also you can check in 20COMM-UM010G-EN-P, pg. 6-12. Otherwise, I never checked if it is possible to retrieve data via OPC directly from the drive, but I think it wouldn't be a good practice if it is possible.

Lynx777 · Sep 5, 2018

I agree with RonJohn, stay away from trying to collect data directly from your vfd's. That would just through the door wide open for potential comm's and security issues.

All of our 753 & 755 vfd's are connected via ethernet, so we get most of the data we want right from the tags for each drive. We also send extra data that we want via datalinks (DCBusVolts, OutputPower, LastFaultCode, etc.). When there is a special circumstance where we want even more data from a drive, we use messaging to collect it. Then the data is collected by the historian system, again via ethernet.

As far as ethernet goes, we divide things up onto subnets. Each production line is on it's own subnet, then all of the I/O is on a subnet, data collection on another, etc.

For example, Line 3's main network would be xxx.xxx.30.xxx, the I/O would then be on xxx.xxx.31.xxx, HMI's xxx.xxx.32.xxx and so on.

einstein_g · Sep 5, 2018

I've actually never connected a VFD to a PLC. I'm assuming one can have a network within which there are multiple VFDs and one PLC.

If I want to collect data from a specific VFD, via a PLC, how do I address that specific VFD i.e do I pass an IP address to the PLC, or would the PLC have tags associated with each VFD?

jraef · Sep 5, 2018

With all Rockwell components, it’s going to be baked in, no need for the Kepware. Find the drives on the network, add them to the project tree in Logix or Studio 5000, then all tags are immediately available to you for whatever you want to do.

einstein_g · Sep 5, 2018

jraef said:
With all Rockwell components, it’s going to be baked in, no need for the Kepware. Find the drives on the network, add them to the project tree in Logix or Studio 5000, then all tags are immediately available to you for whatever you want to do.

@jraef I've been asked to use Kepware for future extensibility to other PLC brands/models.

Dravik · Sep 5, 2018

With the powerflex 753 as an example, If the drive is networked to the PLC, than there will be tags in the PLC for each drive you can reference. As mentioned above, you may need to create datalinks for the information you want.

Kepware will point to the PLC and pull the information from there.
That would be your model normally going forward, get VFD(whatever VFD) to PLC(whatever PLC), Point Kepware at PLC.

This assumes your drives are/can be networked to PLC and your PLC are/can be networked too from wherever you decide to put your Kepware instances.

RonJohn · Sep 5, 2018

einstein_g said:
I've actually never connected a VFD to a PLC. I'm assuming one can have a network within which there are multiple VFDs and one PLC.

Yes, that's the typical way to do things. If you're starting from scratch, I'd highly recommend you look into Ethernet IP communications as it is current, powerful and components are readily available.

einstein_g said:
If I want to collect data from a specific VFD, via a PLC, how do I address that specific VFD i.e do I pass an IP address to the PLC, or would the PLC have tags associated with each VFD?

Without knowing anything about your process, budget, specific hardware in play, data being recorded, etc., we're limited to giving simple, general answers. There are many ways to skin this cat. Dravik gave a solid, general response, given what we've been told. As you learn more about your application, pass it on that we may help further.

einstein_g · Sep 5, 2018

RonJohn said:
Without knowing anything about your process, budget, specific hardware in play, data being recorded, etc., we're limited to giving simple, general answers. There are many ways to skin this cat. Dravik gave a solid, general response, given what we've been told. As you learn more about your application, pass it on that we may help further.

Thanks, make sense. I'll post more information on the application as it's made more available to me.

einstein_g · Sep 5, 2018

How are the links between VFDs on an Ethernet/IP network and a PLC typically configured? Does one use software such as RSLogix/Studio to assign multiple VFDs to a PLC?

After these links are created, does data from the VFDs automatically show up as tags on the PLC, such that I can access them using an OPC server, in the absence of RSLogix?

einstein_g · Sep 5, 2018

RonJohn said:
There are numerous ways the Logix could be communicating with the PowerFlex - digital/analog wired I/O, Remote I/O, Ethernet I/P, ControlNet, etc. Find out what protocol is being used, first off.

Secondly, once you find out what parameters you need to monitor for data collection, set up DataLinks in the drive so that this drive data can be read directly into the Logix. Up to 16 DataLinks can be read from a PF753 to a Logix processor.

If your communication protocol doesn't support DataLinks, then things may have just gotten a bit more complicated.

Just reread this after I posted my last reply. Is DataLinks configured from RSLogix/Studio?

Dravik · Sep 5, 2018

DataLinks are configured in both the drive and in the PLC program.

Rs5000 has a built in function which will let you define the datalinks when you add the drive to the program, then if the drive is available to browse, 'sync' the datalink config between the 2 of them.

Otherwise you would configure the datalinks in the drive and use the same configuration when you setup the drive in Rs5000.

This is not exactly straight forward, I would consult the manual for your drives for better examples. There are addon profiles and other things involved.

Dravik · Sep 5, 2018

einstein_g said:
How are the links between VFDs on an Ethernet/IP network and a PLC typically configured? Does one use software such as RSLogix/Studio to assign multiple VFDs to a PLC?

After these links are created, does data from the VFDs automatically show up as tags on the PLC, such that I can access them using an OPC server, in the absence of RSLogix?

So, this depends on the PLC and Drive.
With a controllogix running say, v20 fw and a powerflex 753 w/ a 20-comm-e module and connected via ethernet - Then yes the datalinks will have tags that you can pull using Kepware automagically.

mdim · Sep 5, 2018

Dravik said:
So, this depends on the PLC and Drive.
With a controllogix running say, v20 fw and a powerflex 753 w/ a 20-comm-e module and connected via ethernet - Then yes the datalinks will have tags that you can pull using Kepware automagically.

I believe "automagically" is a mistake, but really sounds nice. I'm adding it to my dictionary.

OPC/Variable Frequency Drives

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