Replacing Alerton PLCs with Control Logix Keeping Alerton I/O

As some of you may have read in the test section. I have been tasked with looking into ways of removing our dependency on Alerton PLCs without having to purchase new I/O. Some of the things I have looked up seem promising but are not too great on reliability.

It is looking like I am going to need a media converter to connect to the Alerton BacNet MS/TP trunk for the EXP modules. I have two options here, in rack and stand alone. I am leaning towards the in rack option provided by ProSoft. My question is as follows:
The typical configuration and operation of this card is to connect to the devices and pull all data into a pre-defined controller tag in RSLogix (Tag provided by ProSoft). Has anyone modified the operation of these signal converters so that the devices on the converter show up in the I/O tree?

I'm betting not - Rockwell didn't even support that feature with DeviceNet (their original creation). Prosoft indicates that its module uses explicit messaging to talk to BacNet devices; even more remote.

Prosoft is indicating:
Products are listed as “Limited Availability” when product retirement is impending. While a product is in “Limited Availability” it can still be purchased until our limited stock is depleted. Once that supply is depleted, the product will be reclassified as “Discontinued.”

So support / spare parts will be an issue later. Are you sure you want to go down this path of no return?

BTW, welcome to the forum.

Bin it and start again, Point IO is so cheap anyway. Your'll be glad you did on the next IO failure.

Isn't Alerton a BMS? From my little adventure many years ago with a BMS, their architecture is a bit different than typical industrial PLC system. BMS usually don't have many "dumb" IO but instead have some kind of simple controller with it's own IO that receive commands from a central controller. If that's the case, it's not as simple as just replacing the IO, you might have to replace the logic in each of the remote controller units. In that case, using a EIP to BacNet gateway may make sense.

Back to ProSoft module, typically, there's two thing you need to do. 1, setup the module as a generic IO module, 2. add the sample logic from ProSoft (note, some of the new Prosoft module use eds) Once set up, you just read/write to the module data addresses.

Alerton is a BMS. Their I/O and PLCs are a bit different than what most of us are used to. Based on my beginner knowledge of Alerton, you have BCM's which cannot have I/O (PLCs that can compute and communicate). You have VLX's which can have I/O (PLCs that cover the BCM realm and connect to I/O modules). Finally you have EXP (I/O) modules, which connect directly to the VLX via a separate BACnet trunk.

I LOVE the idea of point I/O and have been preaching that from as many soap boxes as I can find. The only issue is the existing system still works and that would be a hard push to get past management. As is this entire project for that manner.

As for the ProSoft front... I saw the limited quantities banner for their BACnet devices but failed to look into what that meant. It is going to be fun when the 20 or so that we utilize here fail (which they will sooner than later). This may be a topic for a new thread but has anyone used ProSoft's in chassis Linux module for proprietary communications? P/N: MVI56E-LDM I am not tied to nor am I in anyway a fan of ProSoft, their stuff works well with Modbus but thats where my support ends. I called customer support over this Linux Development module and he says that its limitations are that of your programming skills. I find this really hard to believe as in my experience, there is always a catch.

You just need a BacNet / Ethernet/IP gateway, right?

Maybe explore other vendors before going on the proprietary route. Have you checked out RTA Automation's product? I found they have an easier (web-based) configuration than ProSoft.

Redlion Dsp data converters (and hmi's) have 4 bacnet protocols on their list. As for modbus and such I prefer them.over prosoft modules.