What are Device-Level Networks?
Device-Level Networks are communication technologies and protocols used to connect sensors and actuators to controllers and/or PLCs. Device-Level Networks come in two choices: "proprietary" and "open".

Proprietary Device-Level Networks are an intellectual property of a particular company. To use them, you must obtain a license, which is granted at the discretion of the owner--usually with many strings attached and a nice price tag.

On the other hand, Open Device-Level Networks are not unique to, or controlled by, a particular company. To be open, certain criteria should be met. These include:

• The full Device-Level Network specification should be published and available for a reasonable price to anyone willing to pay

• The validation process should be well-defined and open to any manufacturer

• Any Network-critical components should be available for a reasonable price to anyone willing to pay

To ensure "openness", a Device-Level Network must allow for:

• Interconncctivity-Devices from different manufacturers can be safely connected to the Device-Level Network

• Interoperability-Elements from different suppliers can be successfully connected together

• Interchangeability-Devices from one manufacturer can be replaced with functionally equivalent devices from another manufacturer.

Why Device-Level Networks?
If correctly selected to match the application, Device-Level Networks offer the user many advantages, both tangible and intangible. Some of these are:

• Device-Level Networks reduce the complexity of the control system in terms of hardware outlay. PLC 1/0 hardware requirements are substantially reduced = cost savings!

• Cabling is reduced from dozens, sometimes even hundreds, of wires to two wires.  The drastic reduction of cabling minimizes or eliminates the need for large junction boxes and control panels.  Also, cable trunking and tracking is greatly downscaled.

• Information from thousands of successful applications have provided impressive proof that the use of Device-Level Network technology can save up to 40% in costs for commissioning and maintenance as opposed to conventional technology.

• As the hardware requirements are reduced, so are the installation times and manpower requirements=cost savings!

• Commissioning of new installations is far more efficient as the diagnostic capabilities and functions of Device-Level Networks identify any connection errors.

• The reduction in control system complexity makes project design engineering easier, quicker = cost savings!

• Creation and maintenance of the previously complicated instrument loop drawings, cable schedules, termination schedules, and wiring diagrams is minimized substantially = cost savings!

• Future modifications, upgrades, and system refurbishment are easily and cheaply carried out.

• Using a well established, industry-accepted, documented system makes the field equipment in your plants interchangeable between suppliers.

• The need for concern about connections, compatibility, and other potential problems is eliminated.

• Due to the superior diagnostic and fault monitoring capability of Device-Level Networks, unplanned downtime and resultant product losses are reduced or eliminated.