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Calibrating and Trimming Instruments via HART

Calibrating and Trimming Instruments via HART. Agenda: What is HART? / History / Signal / Message Frame HART Command Structure Connecting a HART Transmitter Trimming Devices Trimming Conventional Transmitter vs. HART Transmitter Live Demo . What is HART?.

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Calibrating and Trimming Instruments via HART

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  1. Calibrating and Trimming Instruments via HART Agenda: What is HART? / History / Signal / Message Frame HART Command Structure Connecting a HART Transmitter Trimming Devices Trimming Conventional Transmitter vs. HART Transmitter Live Demo

  2. What is HART? HART = Highway Addressable Remote Transducer A digital communication protocol designed for industrial process measurement applications. Uses a low-level modulation (FSK) superimposed on the standard 4 to 20 mA current

  3. Revision Year 2.0 1987 3.0 1988 4.0 1989 5.x 1989 – still delivered today 6.0 2001 – never introduced 7.0 2007 – introduction of HART wireless HART History

  4. HART Signal

  5. HART Message Frame

  6. Three levels of commands • Universal commands • Common practise commands • Device Specific commands HART Command Structure • Universal commands • Model ID • Tag ID • Description • Message • Date • Range Values • Instrument Limits • Process Measurements • Device Status • Common practice commands • Read Variables • Calibration (zero, span) • Initiate Self Tests • Serial Number • Time Constant Values • Device Specific commands • Model Specific Functions • Start, Stop, or Clear Totalizer • Select Primary Variable • Special Calibration Options • PID - SP, Tuning, Etc.

  7. Connecting a HART Transmitter Point-to-point 24V supply Transmitter mA Resistor + HART _ mA Polling address = 0 ! => HART + mA signal HART Communicator

  8. Connecting a HART transmitter Multidrop 24V supply Resistor + _ 4 mA (fixed) ... HART Communicator Addr=1 2 15 Transmitters (max 15 pcs), fixed 4 mA current, Only PV output, different addresses (not 0 !)

  9. Trimming Devices CommunicatorsSmart Calibrators

  10. MC5 Internal Connections MC5 24V supply Transmitter mA Resistor +24V + _ Ground mA HART HART Communicator

  11. HART vs. Conventional Transmitter (1of 2) Conventional transmitter Input 4 … 20 mA • Adjustments: • Zero • Span

  12. HART vs. Conventional Transmitter (2 of 2) HART transmitter Input section Conversion Output section Range Transfer Function PV AO Input 4 .. 20 mA A/D D/A Digital trim Analog trim PV AO

  13. Live Demo Presented by: Ned Espy – Consulting Director Beamex, Inc. Office: 770-951-1927 Mobile: 404-386-8158 ned.espy@beamex.com www.beamex.com

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