Foundation Fieldbus Segment Design
In addition to maximum (total) cable length and repeater count, a host of other details (Note 1) conspire to limit how any particular H1 segment is wired. To help engineers…
Foundation Fieldbus Electrical Parameters
FOUNDATION Fieldbus H1 networks use Manchester encoding to represent bit states: a “high-to low” transition represents a logical zero (0), while a “low-to-high” transition represents a logical one (1). The…
Fieldbus Cables
Fieldbus cable is rated according to a four-level code (A, B, C, or D), each successive letter representing a cable of lower quality6. The following table gives minimum specifications for…
Fieldbus Coupling Devices
In order to simplify the task of connecting Fieldbus devices to such a network segment, multiple manufacturers sell coupling devices (often informally referred to as bricks) with quick-disconnect electrical fittings…
Foundation Fieldbus (FF) Segment Topology
A minimal FF H1 segment consists of a DC power supply, a “power conditioner,” exactly two terminator resistors (Note 1) (one at each extreme end of the cable), a shielded…
What is Foundation Fieldbus (FF) ?
To understand just how different FOUNDATION Fieldbus is from other digital instrument systems, consider a typical layout for a distributed control system (DCS), where all the calculations and logical “decisions”…
Saybolt Viscometer
SAYBOLT VISCOMETER A device used to measure the viscosity of a fluid. The saybolt viscometer controls the heat of the fluid and the viscosity is the time is takes the…
Laser Doppler Anemometer
Doppler Effect is a method for measuring linear velocity. When a narrow laser beam ( or radio beam or ultrasonic beam) is focused on an abject, the beam will be…
WirelessHART device Configuration
WirelessHART field instruments look much like their wired counterparts, with the obvious addition of an antenna. A WirelessHART Rosemount model 648 temperature transmitter appears in this photograph: Note 1 :…
WirelessHART Network Gateway Device
The Network Gateway is a critically important component in a WirelessHART system. It is the sole channel through which all field device data funnels to the host control system. Physically,…
