The DeviceNet protocol dramatically reduces costs by integrating up to 62 devices on a 4-wire trunk network. Communications data is carried over two wires with a second pair of wires carrying power. Discrete and analog devices may be connected into the DeviceNet protocol.

DeviceNet system features

  • More than 30% savings in installation costs over conventional systems.
  • Capability to handle both analog and discrete valve and instrument applications.
  • Power and communication supplied over the 4-wire bus. Capability to install up to 62 devices on the same bus network.
  • Electronic Data Sheet provides accurate device configuration details.
  • Hot insertion of field devices without dropping power. (General purpose environments.)
  • Message prioritizing to enable fast throughput rate for critical information.
  • Technology with proven reliability in millions of mission critical applications.

DeviceNet economic analysis

Sizable installation savings are realized over conventional systems when installing a DeviceNet network. The following is an estimate of installation costs of a conventional system versus DeviceNet (costs are listed in the amount per device):

This analysis is typical of an installation of 20 automated valve systems located in a cluster approximately 150 feet from the I/O rack. Each of the automated valves is located 20 feet apart in the cluster.

The StoneL DeviceNet I/O module and VCT have an auxiliary 4 to 20mA input that is bus powered. (No additional power is needed.) Other analog instrumentation such as flow meters, level controls, pressure sensors, etc. may be wired directly into the module, cutting installation costs further.


DeviceNet analog point addition to StoneL VCTs or I/O modules

When adding an analog device to an existing StoneL DeviceNet VCT, a convenient connection may be made to the nearest device. In the example in figure 3, the level control was 20 feet from the StoneL DeviceNet VCT and 150 feet from the central controller.