Accessing E3 Plus OL Parameters

[IO_Rack 181]

I've done a lot of dabbling with Devicenet on the Logix5000 platform but never really set one up from scratch or ventured into, what was not readily available to me. I have an E3 Plus overload and a CompactLogix L32ER with a Devicenet Scanner. The node addresses are set and the network is up and running with no errors. I would like to access the parameters that are not current accessible by default. Using RSNetworx, I see that I can edit the I/O size via the 'Edit I/O Parameters..." button on the Scanlist tab of the Scanner Properties. How do I map specific parameters from the E3 Plus? Does this need to implemented from the E3 Plus configuration or EDS file? I have a feeling I'm missing a general Devicenet concept here. Edited 5 Jan 2013 by IO_Rack

[Conor 4]

Hi, If you are online (or offline as well) with RSNetworx, click on the Scanner card, normally Node 0. Then Click on Scanlist. Select the Node that your E3Plus is, the Click on Inputs. You should see where the Inputs are being mapped. You will see the same on Outputs. There is a parameter set around parameter 60 (I think) for inputs, that will let you read current or any other values available. These are set up again by the parameters. So if you Have a look at this link http://literature.rockwellautomation.com/idc/groups/literature/documents/um/193-um002_-en-p.pdf It takes a bit of reading, but is all in this manual. I have setup E3Plus overloads on Logix and PLC5's using this manual Conor]]PS. Sorry, I would go online with Networx to change these parameters. Edited 5 Jan 2013 by Conor

[Ken Roach 194]

Conor described the basic idea. I will elaborate. The default Input data connection for the E3/E3+ is called "Assembly 100". It consists of up to four 16-bit Words, which you've probably already seen as the "default" values. Out of the box, these are the summary Device Status (parameter 21) and the Phase A, B, C current values (parameters 1, 2, 3). You can change the parameters that are collected in that Assembly by changing the pointers in Parameters 61, 62 ,63, 64. This is done during configuration of the E3/E3+ and cannot be done dynamically. I frequently use the Device Status, Average Current, Trip Status, and Warning Status. This Assembly can also be shortened; you could make it zero-sized, or just one Word, by entering one or more zeroes in Parameters 60, 61, 62, 63. When the device encounters its first zero, it truncates the Assembly. But an eight-byte packet is pretty efficient in DeviceNet so very few people do this. Anything that's not part of this Assembly cannot be mapped into the I/O table and needs to be accessed using Explicit Messaging. It's not too tough once you get the hang of it, but if you haven't done a lot of MSG instruction programming it can be tricky. Fortunately the ControlLogix/CompactLogix family is the easiest control platform to program these sorts of messages. Once upon a time I wrote some good logic to step through the first 21 or so monitoring parameters of multiple E3/E3+ devices on a DeviceNet, but I don't have access to those old programs, unfortunately. Decide which parameters you want to read, and I'm sure the forum community can help out with the programming of the MSG instructions.

[Ken Roach 194]

Some old examples of DeviceNet Explicit Messaging using the SLC-5/05 and the MicroLogix 1500 controllers are in the Downloads section of this website. The ControlLogix MSG instruction is a lot simpler to configure.

[IO_Rack 181]

As I'm sure they will. We actually have a Tech Connect contract but I felt with the generalization of my question and the fact that I have some time to play with this on the bench, it would be better suited to post in this community. One last thing... You said the Input Assembly cannot be changed dynamically. Ultimately what I would like to do is give them the ability to configure the E3 via the PanelView Plus. So if I deviate from the default settings, I will not be able to set them via Explicit Messaging. Is this correct? I guess my question is... what are the limits of Read/Write via Explicit Messaging? If our customer must call a tech or engineer to reprogram a replacement E3 then I will not need to divulge in a lot of up front programming. I'll just supply them with the RSNetworx file. Thanks again.

[Ken Roach 194]

You're correct that different Output Assemblies can be selected, but the assembly contents cannot be customized. I generally stick with the default Output Assembly because it gives me Output commands and Reset. Neither the selection nor the content of the Input Assembly can be changed "dynamically", in the sense that you can't reconfigure it during runtime and have it take effect right away. The Assembly Number and the contents of Assembly 100 are used when the I/O connection is created by the scanner, after which they're locked. It's like getting your lunch order in to the deli before 10: once that paper is over the counter, you're getting pickles and you'll like it. Reconfiguring E3's during maintenance using an HMI is tempting, but in my experience that feature will be used once or twice a year and it's just as likely that you'll get a a replacement E3 that is the wrong firmware revision or that has modified parameters other than 60-64. I've done this by sending a "reset to defaults" message to the E3, then using explicit messages to set up the Parameters while it's sitting at Node 63, then have the maintenance person change the Node Number. I thought it was spiffy but the maintenance guys still were spooked by the network and would routinely report busted couplings and blown fuses as "the network did something". I think the best tool for reconfiguring E3's in the field is the 193-DNCT, the little DeviceNet Configuration Tool. Along with a parameter cheat-sheet, this is the fastest way to set up an E3 without getting out a computer and RSNetworx.

[IO_Rack 181]

This is a wealth of knowledge and experience that would not be found in any manual. I can see my ultimate goal in setting the E3 is probably more trouble than it is worth. In fact, I was on a service call earlier this week (not the same project) where: A) The new E3 was a higher firmware revision. B) They blamed the E3 when the trouble ended up being bad motor wiring in the bucket. I will take your advice at this point. I still may need to do some Explicit Messaging after we agree on what monitoring parameters they would like to see. I probably won't get any bench time with it until later this week but at least now I what I need to do. Thanks for your expertise.