PC with ModBus adapter built in?


Thread Starter


I have a business need that requires a PC (Running Linux/Windows, no CE or embedded) that hopefully has a RS-485 port built into the motherboard.

I'm looking for a vendor that could supply such a computer or perhaps an alternative? The main requirements are RS-485 and Windows XP (or perhaps Linux).

Any suggestions?


curt wuollet

Many PC104 units include ports capable of RS 485 as do some "industrial computers". You must understand that our friends at Microsoft and Intel have made a concerted effort to eliminate serial ports completely to push USB. Look at embedded class boxes as well unless you absolutely need a desktop.

I believe the plug computers have 485 as well. Anything designed for "headless" use will often have enhanced serial capability.

It depends on what are you looking for besides RS-485. It's hard to make a specific recommendation, as you haven't stated why you want the RS-485 to be on the motherboard rather than on a plug-in board.

However, Advantech sells PCs with RS-485 in both ATX and mini-ITX formats. A quick Google search will also turn up plenty of mini-ITX vendors with RS-485. Some of the non-standard "industrial computers" also have this.

If you are looking for something in the typical PC size and form factor, look at ATX boards. If you need low power and compact size, look at mini-ITX. If you have some really special requirements, look at the "industrial computers".

In either case, check with the vendor for compatibility with the operating system of your choice. There normally isn't a problem, but occasionally you will find hardware which used an obscure chip that doesn't have any drivers. I would try to stick with the ones that have the most common chip sets, as dealing with special drivers can be a pain when maintaining, upgrading, or replacing a system.

You will also need to pick out a case, power supply, disk drive, etc. If you don't want to assemble it yourself, talk to the vendor whether they do this for you. I have dealt with Advantech where I told them what features I wanted and they provided an assembled and tested system. Some of the other mini-ITX retailers (as opposed to the board makers) may do the same.