networking plc's

I have a problem,


In a factory we have 3 SLC-500 machines each (except 1) connected to a panelview screen. We also have 2 Micrologix 1500's, each using the rs232 to communicate to a screen, and the Mini Din used to an external modem. What we want to do is network all the PLC's on a dh-485 or LAn to collect various information via a common computer. The Slc-500's are going to be easy to connect to a Dh-485 network, but the micrologix 1500's are rather difficult. we have used AB website to find a way to network all these units to a dh-485 network or a LAN, and it has been unsuccessfull. The closest thing we have found is the 1761-NET-AIC adapter to connect the Micrologix 1500's to a Dh-485 network with the SLC-500's; however, even with the adapter we have no serial port to connect the external Maple System screen, because we used that serial to connect to the adapter and the mini din port has been used to power the 1761-NET-Aic. Even if we didn't use the mini din to power the adapter, we have used both plug in's in the cabinet, so an external power supply to power the adapter is out of the question Anybody have any ideas, based upon the fact that the modem and screen must be connected (and communicating, no just hanging from duct tape) with the micrologix 1500

Current setup:
SLC5/(01 ?) DH485 to HMI.
SLC5/(01 ?) DH485 to HMI.
SLC5/(01 ?) DH485 not used
ML1500 DF1 to Modem, DF1 to HMI
ML1500 DF1 to Modem, DF1 to HMI

Suggestion:
SLC5/03 DF1 + 1769-NET-ENI to Ethernet, DH485 to HMI.
SLC5/03 DF1 + 1769-NET-ENI to Ethernet, DH485 to HMI.
SLC5/03 DF1 + 1769-NET-ENI to Ethernet, DH485 not used.
ML1500 DF1 + 1769-NET-ENI to ethernet, DF1 to HMI
ML1500 DF1 + 1769-NET-ENI to ethernet, DF1 to HMI
Configure a connection from the outside world via LAN in stead of the modem.
You would have to exchange the SLC500 CPU's for at least SLC5/03's.

I understand what you mean about the modem. Our company didn't put it there, so we are not sure if someone else can dial in using that modem---not sure what it's used for. The modem is connected via the mini din....the screen is connected via the rs-232. As far as ethernet, we are definetely looking into that; however, the cost of the ethernet devices are expensive over $500 for each micrologix 1500 machine. So we are looking for the most cost effective way also (maybe give the factory a couple options to do it). However, like your mentioned, the modem i think is going to have to be removed any way we do it. The best option i've found thus far, is replacing the micrologix machines with SLC's

PS all SLC's are /03 or better

You can also use the AIC+ (1761-NET-AIC). It has three ports, two RS-232 and one RS-485, all of which communicate using DH-485. You can connect the O/I to one 232 port, and the PLC to the other 232 port, and the 485 port to join the PLCs. We usually use two AIC+ units per PLC, connecting the O/I to one via 232, connecting the PLC to the other AIC+ via 232, and connecting all AIC+ units to each other with the 485 terminal strips. That leaves a spare 232 port for programming from the laptop with the 232 port and a PIC driver.

At least some of the MicroLogix 1500's have two serial ports, and you may be able to connect CH0 to your O/I and CH1 to the network. We've done that too.

A-B can be fussy using DH-485 on modems not provided by A-B. Timing issues I believe.

One word of warning:
If you are considering to put everything on DH485, then the low speed of the DH485 (19200 baud) will be a bottleneck.
You would be putting 5 PLCs, 4 HMIs and one PC on the same network, so you will need something a little bit more potent than DH485.
If the systems are working acceptably at the moment is because you have individual DH485 connections, not a common network.

edit: OK, you will only be putting 2 HMIs on the DH485 network, because the ML1500 hangs off another port.

speed is not critical in this application...it's only going to be used to collect various information/data

OK, but the current HMI panels on the SLC500's will have the online connection degraded when you connect everything on DH485. But maybe its not so critical for you.

A lowcost solution could be to exchange the SLC500's with ML1500 with two serial ports.
The existing PVs would have to be exchanged also, you could get the same as the ones connected to the existing ML1500's. Then you have a completely uniform system - all ML1500 having its own HMI hanging off a dedicated DF1 port, and everything connected together over DH485 + 1761-NET-AIC+ on the other ports.

I think that would still costs a lot to replace the SLC's, and even at that, I would rather have SLC's running than all micrologix. For just data collection, i'm sure the company doesn't want to spend that much money to replace the Plc units. Thanks for everyones help though

HI! I'm student and I have to netwok some PLCs on a similar way. I have 1 SLC5/03, 1 SLC5/02 and 2 micrologix 1000. I want to network them all in a DH-485 network. I also have the following devices: 2 1747PIC, 2 SLC500 link coupler (1747 AIC) and cables 1747CBLAM00, 1747C10..... my specific problem is that I want to know if I have to buy another device to serve as the concentrator or so, for the DH4-85 backbone. Can u help me?. I want to know how to do the connections. The 4 devices I want to network end up with a DH485 interface, and then what?.....
Which configuration should be implemented in each device in order to do the network?.

Thank you very much!