Networking AB 503

[Tommy Davidson]

Need to Network AB 503 PLC. In past have used AB 1761-NET-ENI. These interfaces are rather pricey. Does anyone know of a more economical device?

[JesperMP]

If you have to do messaging between the SLC's, then I dont think there is a more cost effective way (you might save a little by going the DH485 way).

If all you need, is to connect from your RSLogix or other single point comms partner, then you could use a commercially available ethernet to serial converter.
They seem to come in droves right now from a plethora of vendors. Try "Serial to ethernet converter" or "Ethernet to serial converter" on Google.

[Tom Jenkins]

Network to what? How many of them? What kind of response time is needed? How far apart are they?

I generally use DH-485 and AIC+ to connect several SLCs and a couple of O/Is.

[Tommy Davidson]

Will be connecting to our internal Server using TCP/Ip Protocol. Will be posting machine performance data on internal web page.
Thanks,
Tommy D.

[Ken Roach]

You're running an A-B Ethernet driver right now, probably in RSLinx Professional. The 1761-NET-ENI translates between the A-B Ethernet protocol and the A-B serial protocol (called DF1). No other device on the market does that, so there is no direct replacement for the functionality you have now.

What virtually all RS232/Ethernet devices do instead is make use of a "Port Redirector". This is a software element that would reside on your webserver computer and emulates an enumerated COM port, like COM4 or COM5 (up to COM31 in Windows). It intercepts calls to that COM port and redirects them across TCP/IP Ethernet to the serial port device.

This means you'd have to change over to a DF1 driver in RSLinx, and you'd be limited to 31 of them.

I prefer Lantronix, because their quality and support is good. You may be disappointed with the ease-of-use, though; there are a handful of threads on this Forum that detail users spending several days trying to set up these inexpensive interfaces.

All in all, I think the Net-ENI is worth the money, as that money pays my rent.

[Jiri Toman]

There is a device on the market made by DIGI which has been touted as
an EtherNet/IP ready. DIGI markets this device as DigiOne IA RealPort.
I have used DIGI devices before for RS-232 Ethernet tunneling. They work OK. The device which supposedly does EtherNet/IP has no instructions on how to set it up to communicate with one of the
three RSLinx's Ethernet drivers. When you look at their web site they have one app note on this with some incomprehensible statement about the use with EtherNet/IP and how to setup an EDS file for it.
I have one of these devices and because of the lack of info I have ended up using it in a tunneling mode with their RealPort virtual COM Port software and DF1 driver in RSLinx.
There is one more thing you should be aware of. When interfacing to the virtual COM port software, the regular Microsoft MSCOM active X
does not work reliably. Whenever I need to get data from a virtual COM Port I use the SaxSoft's version of MSCOM. That one works 100%. In the hind sight I wish I would have bought the 1761-NET-ENI.
If you do use the DIGI device make sure that you buy one that's DIN rail mount, their cheaper desktop model is poorly packaged for industrial environment.

[jshiepe]

Just thought I would share a little caveat about the NET-ENI that I didn't find out about until I had faulted out a SLC5/04 processor a couple of times over the course of a few days. There are limitations on the amount of data that can be passed through these modules. See the following tech note:

http://domino.automation.rockwell.co...5?OpenDocument

Unfortunately, I found this too late and as a consequence now have to purchase an $1800 ProSoft module to put in the rack to achieve the throughput I need. I guess the funny part of the story is that I was using the NET-ENI to replace a NET-AIC that was communicating DH485 back to my SCADA node and collecting the same data points. Also on the DH485 network were 2 other 5/03's. The 5/04 never crashed with the NET-AIC, as a matter of fact, the NET-AIC is back in place performing just fine until I can get the ProSoft module up and working.

[Tommy Davidson]

Thanks for all the resopnses. Looks like I will just bite the bullet and stay with the A-B stuff. It works very well,and I guess in the end you always "Get what you pay for"

Thanks again,
Tommy D.

[Jiri Toman]

I have now managed to get the DigiOne IA RealPort operating in
EtherNet/IP mode. In fact it's fairly easy to configure and it works well so far, no crashes. As opposed to the NET-ENI, DIGI does not support inter processor communications yet. You can't do MSG's.
They tell me that they are releasing new firmware in the near future which will take care of that.

Jshiepe,
This device costs around 500.00 USD. That would save you some money.
Problem is that DIGI's web site does not explain how to set it up for
RSLinx / Ethernet communications.
The trick to configuring it is as follows:
Once you get the basic Web browser config screen going (that part is explained well in their literature), you need to select the port config for IA and set up the DF1 port config to match your PLC even though you will not be using DF1.
In RSLinx you will use the Ethernet Devices driver and specify the
IP address of the DIGI.
Reboot the DIGI and it should work.

I like DIGI's packaging. It's small footprint, DIN rail mount
and they have lots of diagnostic LED's.

[jshiepe]

Jiri,

Thanks for the info. I believe I paid @$500 each for the NET-ENI's also. Do the Digi units have the same data throughput limitations as the NET-ENI's? If not, they might be worth a look for me.

[Jiri Toman]

jshiepe,
I don't know the answer to that, I also don't know how many connections you can have when you run Ethernet/IP. I think that the cost is a little less than the NET-ENI.
Here is the e-mail of an app. engineer I talked to in DIGI.
JOHNRC@DIGI.COM
He told me that they have an engineer on staf who used to work for AB and was involved in the design of NET-ENI.
I am sure that he could answer that question.

[jshiepe]

Thanks again Jiri. I sent John an email, and I'll keep this thread posted when I receive his reply.