P-NET Introduction and Installation

P-NET is an international fieldbus standard (IEC 61158 type 4). The physical layer of P-NET is based on EIA RS485. (Read more…)

/the-p-net-fieldbusP-NET using RS485 allows for two different installation techniques: ‘P-NET’ and ‘4-WIRE P-NET’
The same rules concerning cable lengths, number of nodes, communication speed etc, apply to both installation variants.

With 4-WIRE P-NET, both communication and power supply are included in the same bus cable.

Connecting P-NET modules in the ‘traditional’ way, establishes a communication link between a number of individual nodes, with each having its own power supply.

By using the appropriate adapters and the correct installation techniques, P-NET and 4-WIRE P-NET networks can be mixed within an installation and still maintain a fully transparent system.


P-NET can be installed using a number of different techniques and topologies. 

Select one of the topologies below for further information.

P-NET Ring Topology

The P-NET cable is connected to a number of devices in a way that forms a physical ring. Each device on the ring is connected using the same principle.

P-NET Bus Topology

All nodes between the two termination nodes are connected in the same way as modules in P-NET ring topology.

P-NET Redundancy

P-NET redundancy provides an additional communication network path between a number of M36 clusters.

4-WIRE P-NET Topology

4-WIRE P-NET is a wiring principle that enables a number of simple devices to be connected by means of a single cable.

P-NET Light-Link

P-NET Light-Link provides an optical communication link for P-NET. Light-Link provides galvanic isolation between each member in a communication chain.

The P-NET Fieldbus

P-NET - IEC 61158 type 4
General description

P-NET modules which use the traditional methodn

PD 340 Flow Transmitters
PD 3000 Family
PD 4000 Controller
PD 5000 Controller Family
PD 600 Family (M36), when using BM 002 or BM 010 base modules

4-WIRE P-NET modules
PD 681
PD 600 Family (M36), when using BM 012 base modules