Compactlogix Enet Comm to Lantronix USD1100

[brettdawnj]

I have an application that currently is running on a CompactLogix L35E with a devicenet network. Off the devicenet, I have some Vorne Digital Displays that are driven serially. In order to make these work, I have used a ANYBUS communicator to convert the data from a devicenet connection to serial. The problem that I have with it is I have to do some funky conversion of data in and out of ASCII formats and the 16 virtual displays that I have have slower than desired update times.

I am thinking of converting this system to an EthernetIP connection so I can send ASCII data out directly from the PLC instead of the current conversion process I use. My thoughts are that by using the E-net connection I can speed up the update rate by sending one longer string of ASCII data to all the displays at one time and let the displays use the data they need.

With transitioning to E-net communications, I can't directly understand if I can communicate to this module without having to purchase the RSNetWorks for Enet. I was hoping that since this is actually done by one ASCII string of 100 characters or so to ones serial input of the displays, that I could write a message instruction to take the ASCII data out the Enet connection and have it arrive at the Lantronix UDS 1100 every 3 seconds or so.

Does anyone know if I can send out a simple ASCII string via this compact logix E-net prot with just properly configuring a message instruction (without the purchase of additional software)? And, if this can be done, can someone help me get started on the proper configuration for this message statement? Note the communications only needs to be done one way (just simply out the E-net port to the Lantronix box with out any type of special handshaking configuration... just a simple ASCII string of +/- 100 characters or so).

Any help, guideance or suggestions would greatly be appreciated.

Thanks, Brett

 

[brettdawnj]

Wow, I have just learned in the past evening that what I want to do is not so simple. I trust that maybe why there is no responses or comments on this one yet.

I got access to a computer that had RSWorks for Enet, and found out that in order to make this communication work, one needs an EDS file for the product that we are communicating to. From Lantronix, I can't find such an animal. They tell me to contact the AB guys as it is there configuration set up, and the AB guys tell me that they don't think it can be done... I must have a misunderstanding as to what open systems are.

Bottom line is does anyone know if it is possible to configure a Lantronix UDS 100 (a simple Ethernet to serial converter) to listen to the enet port on a compact logix processor for simple message strings to it's ip address by just adding a new module of "Generic Ethernet Module" to the enet communication (including the proper configuration settings) and then getting the system to write data to the module via a message instruction (including the proper message configuration)???

Or am I all out of whack on what is possible?

Thanks, Brett

 

[Ken Roach]

I know that the specific thing you're asking about is not possible. EtherNet/IP is more complex than "open a socket and send raw data", and the UDS1100 does pretty much only that.

RSNetworx for EtherNet/IP really doesn't apply to this application. It's only necessary for some troubleshooting and modeling purposes.

I'm surprised that your DeviceNet gateways are considered too slow. What kind of update speeds are you looking for ?

There is a neat EtherNet/IP to ASCII converter from Real Time Automation that several of my barcode using customers absolutely adore. It polls the Logix for String tags, rather than having you send a MSG to it.

 

[brettdawnj]

Ken (and/or anyone else),

There is 2 problems that I have with the devicenet connection. The first is that I could not get the Compact Logix Processor to send out and ASCII text string. The only way I was able to figure out how to get it ASCII data was to send out decimal equivelents to the ASCII data. It was not pretty. I had to take integers byte by byte and by checking the contents, put the ASCII decimal equivelents out an output address. Then I have an ANYBUS devicenet to serial device that I am using to convert the decimal equivelents back to ASCII. At the time I wrote this logic, I couldn't find anyone at AB that could show me how to get ASCII data out a devicenet connection.

The second issue is more of a "display update" issue. I am running 16 virtual displays that all are communicated to one at a time. I can only seem to drive this logic successfully thru the PLC and the ANYBUS module at about every 20ms without having failures in updates. In the application, the 16 displays are all visible at one time... they are all stacked next to each other. Every 3 seconds, I change the purpose of the displays from Daily Data to Cumlative Monthly Data. So the application flips back and forth all day long (a simple but cost effective way of sharing lots of data). The issue becomes that the displays don;'t look great when they flip from Daily to Monthly as you can physically watch the updated go across the displays. I have done this type of application before with remote I/O and I can get instant transitions between modes (not noticible to the human eye or brain).

So with both of these issues, my thoughts were to make the displays into one long ASCII string of just one display, and then hoping to get the 100 characters or so and merge them into a string and blast the message out every 3 seconds. This way, I know the displays all update without any notice of any lag time.

Any suggestions or thoughts would be really helpful at this stage.

Thanks, Brett

 

[mikeatwell]

Hello Bret,

I know you posted your question a couple of months ago, so I apologize if you have resolved this issue.

I also know you said in your post that you would like to do this without purchasing additonal software, but would you consider using third-party software to do this? I'm an engineer at I/Gear, and we have a software called Data Transport Utility that can do the PLC to Vorne communication.

I'm assuming you have RSLinx since you have a CompactLogix PLC. You would need a version of RSLinx that has the OPC Server component, i.e. Pro or better, since our software communicates to most PLCs via OPC. This will work whether you stick with DeviceNet or move to Ethernet, though I have always used Ethernet where possible because of the speed and distance advantages.

The communication to the Vorne displays would be done natively through a TCP/IP connector (we call our connections DataLinks). An update rate of 3 seconds would be no problem, though I usually use a more deterministic method for updates, e.g. update on the change of some tag in the PLC. I've used the Lantronix converters successfully on several occasions this way.

The advantage of this over a more home-grown method is having the ability to manage the data sent to the displays more easily. To set up the above transaction to a single display, might take a half-hour or so once the the software is installed.

If you are still interested in this solution, please try out the software. You can download a demo at http://www.igearonline.com/downloads/default.asp.