Is it possible to use a Powerflex 525 as a Remote IO?

I thought I remembered a forum post here asking this, but either I was mistaken or the search terms are too vague and I can't find it.

I have a CompactLogix PLC controlling a PowerFlex 525 via Ethernet/IP.

I'd like to get an 0-10V analog signal back to my PLC from that remote location. Is it possible to wire it to the 525's Analog input and then read that value via Ethernet/IP?

I did look through the default tags created when I add the PF525 to the Compact's IO list, but it doesn't appear to be there. Is there an Explicit Message type I could use or something like a GSV?

Thanks,

You could retrieve the on-board analog input value by adding a Read Datalink pointing at d360 [Analog In 0-10V] or d361 [Analog In 4-20mA] (depending of the on-board IO setup) within the PF525 Module Definition; the value represents % of the full scale..
There are four Read and four Write Datalinks which could be used in addition to Status/Feedback and Command/Reference default ones.

Page 42 of http://literature.rockwellautomation.com/idc/groups/literature/documents/um/520com-um001_-en-e.pdf

Alternatively, you could Explicit Message (CIP Generic/Get Attribute Single) and access the DPI Parameter Object of the EtherNet/IP adapter.

Page 72 of above posted link.

Hi Tharon,

We have a line of Ethernet IP remote IO modules that you can use for your application. Our EIP-2017 has 8 AI channels. In the product manual, simply follow the quick start guide to connect to your AB PLC.

https://www.icpdas-usa.com/ethernet-ip-data-acquisition-table.html

If we can help with any questions, please let us know.

Thanks, dmargineau. That's what I was looking for. Now I feel a bit silly since it's right there in the module definition and manual.

I've never actually done it, but as dmargineau suggests it can definitely be done. Our rockwell rep actually suggested that once, on a job we quoted which had say 20 tanks, all with an outlet valve, pump, and analog level sensor adjacent to one another. The pump was controlled with an IP56 VSD mounted locally, so the solenoid was controlled by the relay output of the drive, and the level was read from the drive's analog input, all done over ethernet. Unfortunately the scope of the job changed quite significantly and we didn't end up getting it, but it would have been quite a nice neat solution!

The ability to do that is one reason we are installing 753s for our new VFD installations. Just add a card and set up the datalink and you have all sorts of added I/O for your use. We use ours for motor disconnect auxiliaries, jog PBs, and anything else that may conveniently be run in the conduit along with the motor power wires.

Yes the drives IO can be handy. We use the new motor cable that has two wires for the local disconnect in it. We wire the local disconnect to the enable input and then read that input as a Datalink to show the state of the local disconnect on a screen.
I have used the drives analog input before for a jog speed from a jog pendant when the system had no analog inputs.

Remote I/O or Distributed I/O?...

Tharon said:

Is it possible to use a Powerflex 525 as a Remote IO?...I have a CompactLogix PLC controlling a PowerFlex 525 via Ethernet/IP

Click to expand...

I could be really smart and say "No. It is not." But, I'm not trying to be smart, just particular, if you'll forgive me.

Remote I/O is Distributed I/O, but, Distributed I/O is not Remote I/O, even though the I/O happens to be remote from the controller. It's just Rockwell/AB terminology but I always feel it can lead to confusion when these two terms are mixed up.

The above is just a distinction I like to make as the long standing "Remote I/O" or "RIO" option is quite specific in the Rockwell world as a particular means of Distributing I/O and does not refer to all or any means of Distributing I/O. For I/O that is remote to the controller's backplane, but not specifically "Remote I/O" as in "RIO", I would use the term "Distributed I/O". RIO is Distributed I/O, as is EtherNet/IP, DeviceNet, ControlNet, etc. I would not, as best practice, call EtherNet/IP "Remote I/O", even though I'm sure most will understand what you mean.

This is just some passing advice on the topic at hand for all and not in particular to this case...

Tharon said:

...I'd like to get an 0-10V analog signal back to my PLC from that remote location. Is it possible to wire it to the 525's Analog input and then read that value via Ethernet/IP?...

Click to expand...

While we can say it is possible, I am considering here more the question of should we?...

I would say, if needs must then needs must, but, if a device signal is required back to the controller, and it is not directly related to the drive or its application, then I would advise not adding it in through a drive's Datalinks or explicit messaging. This can save you a lot of work up front but possibly add a level of complexity that someone else may not appreciate down the line. If the signal is not related to the drive, in any way, then I would, at a minimum, attempt to add the signal device to the network as a node, and communicate the data more transparently. That is, of course, if the end device supports such a network, or can be converted to as such. It may be possible to provision the device onto the network close to the drive location, which is already on the same network i.e. add it to the network where the drive is already connected. A local switch, for instance. If the network topology somehow dicates a "home run" cabling, then again, it's back to the "needs must" scenario. If you must get it directly back, but it is not related to the existing application, then I would advise attempting to do so. Else, you add it in through the drive in a less transparent manner.

If the signal device is directly related to the drive and its application then I would wholeheartedly support the use of Datalinks to communicate such signals.

But explicit messaging?...

Tharon said:

...Is there an Explicit Message type I could use or something like a GSV?...

Click to expand...

Another point to be careful with when choosing to use Datalinks to and from a drive as opposed to explicit messaging is the drive's Non-Volatile Storage (NVS). When you use explicit messaging write to the DSI Parameter Object you are also writing to NVS. If you write quite often in a cyclical manner then you may prematurely exhaust the life of the NVS. This will render the drive faulty and it will need replacing.

If you use Datalinks then the written data to the DSI Parameter Object is not saved to NVS, but is lost on power cycle. This will save the life of the NVS. This is why you are advised to use Datalinks for frequent parameter changes in these drives.

There is also the option to disable NVS writes entirely (C121 [Comm Write Mode] = 1 “RAM only”), but do note that any current parameter settings will be lost on power cycle and will require reinitialization.

And to finish off, here is some info on how you would do the opposite to the above request i.e. configure Datalinks to allow a controller write to an analog output connected to a PowerFlex 525 drive...

531277 - PowerFlex 525 drive: Analog Inputs and Outputs / Use of PLC and Datalinks to analog output
Access Level: Everyone

Just to be clear - I am not saying that the signal in your case, Tharon, is not related to the drive or its application. But more that the above should possibly be considered where it isn't related. The above is intended more as "best practice" advice, than anything else.

Regards,
George