Tecfluid MX4B - Manual (Page 18)

18
HART
1 INTRODUCTION
HART is a bi-directional communication protocol that provides data access between
intelligent field instruments and host systems. A host system can be any software
application from a handheld terminal to control plant processes, asset manager, safety or
other system using any control platform.
HART protocol is based on a current loop, and has the peculiarity that provides two
simultaneous communication channels, the analog signal of 4-20 mA and digital signal.
Signal 4 to 20 mA communicates the primary measured value (in the case of a field
instrument) using the 4-20 mA current loop.
Additional device information can be transmitted by a digital signal superimposed on the
analog signal.
MX4H Converter is a field instrument that meets the HART protocol revision 6.0.
This document specifies all the functions implemented MX4H regarding the protocol
converter.
MX4H Converter is fully compatible with the HART Server software from HART
Communication Foundation.
Tecfluid S.A. do not guarantee that the MX4H converter is compatible with the different
servers on the market.
2 DEVICE IDENTIFICATION
Manufacturer: Tecfluid S.A.
Model: Converter MX4H
Manufacturer identification
code:
204 (0xCC)
Device code: 141 (0x8D)
HART revision 6.0
Number of device variables: 2
Physical layer supported: FSK
Device category: Transmitter
3 DESCRIPTION OF LOOP CURRENT
There is one current loop.
The current output is related directly to the measured flow rate of the process input, which
in turn is the primary variable (PV).
The output range is from 4 mA to 20 mA for full scale output.
The maximum current drawn is 20 mA at and above 100 % of full scale.
The Multi-Drop (loop disabled) current is 4 mA.
The receive impedance is Rx > 8,5 MΩ and Cx < 200 pF