Device Net - Technical Snapshot

Technical Snapshot

1. Defines the media, physical, data-link, and application layers of the ISO/OSI 7-layer model (see Open Systems Interconnection)
2. Incorporates trunkline topology with separate buses for signal and power (Typical configuration: two twisted pairs and a single shield)
3. Baudrates defined: 125 kbit/s, 250 kbit/s, and 500 kbit/s
4. Trunk length is inversely proportional to the speed, i.e. 500, 250 and 100 meters respectively
5. A not-so new flat cable was added to the specification to allow the use of the quick-fix connector
6. Up to 64 nodes on a single logical network (node addresses range from 0 - 63). The network has a low node priority scheme
7. Supports master/slave as well as peer-to-peer communication, although majority of the devices work in the master/slave configuration
8. Allows multiple masters on a single logical network
9. Network cable can supply device power along same cable as communication cable (Generally smaller devices such as photo-eyes, limit switches, and proximity switches).
10. Networked devices can be simultaneously controlled and configured
11. Engineered to withstand noisy environments
12. Supports four message types to/from slave devices (strobed, polled, cyclic, COS (change of state)). Some devices support more than one message type

References