Distributed/remote I/O buses/networks--which should you support?

FEBRUARY 4--A recent study by Venture Development Corporation (Natick, MA), a technology market-research and consulting firm that specializes in industrial and commercial electronics, computing, communications, software, and power-systems markets, identifies the top five control-network interfaces for use in industrial distributed/remote I/O applications.

For all DCS, PC-based, and PLC product classes combined:

2002:
1. Profibus DP
2. Ethernet (10 Mbits/s)
3. DeviceNet
4. AB Remote I/O (tied)
5. Foundation Fieldbus H1 (tied)

Expected in 2005:
1. Profibus DP
2. Ethernet (10 Mbits/s)
3. DeviceNet
4. Foundation Fieldbus H1
5. Fast Ethernet (100 Mbits/s)

Although Profibus DP is expected account for the largest share of shipments for distributed/remote I/O, Ethernet-based network connectivity is projected to contribute the most to market growth over the forecast period. However, Ethernet by itself is not a complete network and in particular requires an application layer protocol, of which there are many presently in use.

Which Ethernet protocol or protocols a vendor chooses continues to be at the discretion of the vendor, as there is no clear frontrunner. By waiting to see which protocols find the widest acceptance, a vendor may get into the market too late. The better approach may be to develop products for those perceived as showing good potential such as Ethernet/IP, Modbus TCP, and ProfiNet.

All vendors should develop distributed/remote I/O products that interface with open bus/network protocols, as demand for use with proprietary protocols continues to fall.

For more information, see www.vdc-corp.com/industrial/press/04/pr04-04.html