Net ENI vs Digi One IAP

wlemst88 · Jun 16, 2005

Hi all,

I have a question for you gurus. I'm looking at connecting a bunch of PLC 5/20s to a SCADA machine, but I'd also like to have a network connection so that I can do some online programming. This requires two consecutive connections. I know that the Net ENI can do 6, buts its quite expensive. The Digi One is a couple of hundred less, but I can't seem to find anywhere how many connections you can have.

Anyone out there who knows?

Thanks in advance.

sportster · Jun 16, 2005

I'm not sure if your situation is the same... At the facility I'm at we have 14 MLX1500's with the NETENI modules. All are connected to a SCADA somehow and we go online with them A LOT. No problems. We can't do online edits (MLX doesn't support it), but I don't see why that should be a problem. The only issue we have is if a power blip happens; sometimes the NETENI's have to be powered down and back up to re-establish a connection. Hope this helps.

Patrick Lisowski

Jiri Toman · Jun 16, 2005

This requires two consecutive connections. I know that the Net ENI can do 6, buts its quite expensive.

Did you mean to say concurrent / simultaneous?
If you did, then Digi is not what you should use. It only supports one connection as far as I know. The cheap Digi One, the RS-232 tunnelling device, also requires RealPort software to be installed which is a maintenance hassle. The Digi One IA works like ENI without the capability to send MSG's between processors. I don't know how many connections it supports but price wise it is not much cheaper than ENI.

OkiePC · Jun 16, 2005

Why not use a DH+ network? You can group the PLCs in sections of up to about a dozen per network and put a 1784-ktxd card in the SCADA machine. We have three DH+ networks with about 35 nodes total which connect to a central PC. I can (using RSLinx gateway) go online to any of them from my desktop via ethernet to the central PC. DH+ is very reliable and fast enough for most applications.

wlemst88 · Jun 16, 2005

Yes, I did mean concurrant/simultaneous.

Here's the response I got from Digi Tech Support... Don't really understand the reply.

****
This would be "at least 60".
Have 2 SCADA poll the PLC at the same time RSLogix runs (2 sockets worst case) should NOT be a problem for the DOIAP.

***

Yes, I thought about DH+, but unfortunatly some of the more critical PLC's don't have any spare DH+ ports. I know I could mix my add my SCADA server to an existing control network, but I worry about what that will do to bogging down the network. There's a fair amount of data I want to collect, and I'm thinking it'd be best if it was on an isolated channel.

wlemst88 · Jun 16, 2005

I got a clarification from the DIGI tech support, apparently you can have up to 60 connections to the PLC at once, and he's personally tested two.

So it sounds like a good/cheaper alternative to the Net ENI thing as you get 10 times more connections.

brianjdavis · Jun 16, 2005

It is possible also to use a Lantronix DeviceServer. If you can use passthrough over RS232 you can access the whole DH+ network from a single device. I have 6-8 of these running in my remote plants including 2 in Mexico.

wlemst88 · Jun 16, 2005

I suppose that would only work if you have a DH+ network you can use. I don't in this case.

Did you do that with AB PLC 5's?

brianjdavis · Jun 16, 2005

Did it with SLC's but it works over the standard serial protocol. It was mistake I thought you were impying that you had a DH+ network between your PLC's already. The way I use it is connected to the serial port and with the passthrough configured pass messages over to the seperate DH+ network internally in the CPU.

Jiri Toman · Jun 16, 2005

It is possible also to use a Lantronix DeviceServer. If you can use passthrough over RS232 you can access the whole DH+ network from a single device. I have 6-8 of these running in my remote plants including 2 in Mexico.

Hey Brian,
I didn't know that Lantronix device could do that?
Could you publish the exact catalog number of the device or provide a link? Are you sure that you are not refering to the DataLink's device?
Thanks

brianjdavis · Jun 16, 2005

Lantronix Xpress DR or DR-IAP, the DR-IAP supports the DF-1 and Modbus protocols with different drivers but we have just used the standard driver with great success.

http://www.lantronix.com/device-networking/external-device-servers/xpress-dr_dr-iap.html

Net ENI vs Digi One IAP

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