Pressure Transmitter Workshop Re-range - [HART 475 / Fluke 789 / Druck DPI610 / Foxborough TX]

Pressure transmitter re-range and calibration check (tutorial)

Purpose

Demonstrates re-ranging a Foxborough IG10P pressure transmitter from 0–10 bar to 0–5 bar and performing a 5‑point calibration check.

Test equipment used

• Druck DPI 610 IS — pressure source/calibrator (pressure application and pump)
• Fluke 789 ProcessMeter — provides 24 V loop power and reads mA output
• HART 475 field communicator — HART configuration and send-to-instrument
• Mechanical adapters/tubing — 1/2” NPT to 1/4” Gyrolok adapter, PTFE tape, small‑bore tubing and olive fitting
• Paper calibration/check sheet (5‑point)

Procedure (high level)

1. Mechanical connections

   • Removed transmitter back plate and wired two leads to the Fluke 789.
   • Fitted a 1/2” NPT → 1/4” Gyrolok adapter; used PTFE tape on the NPT threads and tightened with wrenches.
   • Connected Gyrolok tubing to the Druck DPI 610.

2. Pressure application and leak check

   • Pressurized with the DPI (air used in demo; hydraulic pump recommended for higher pressures).
   • Held at 5 bar briefly to confirm no significant leak, then vented.

3. Loop powering and initial readings

   • Fluke 789 set to loop‑power (mA source); red to positive, black to negative.
   • Observed ~3.99–4.00 mA at atmospheric pressure (expected 4.00 mA for 0 bar on a 0–10 bar range).

4. HART re-range (PV rearrange)

   • Connected HART 475 to HART pins and went online.
   • Confirmed LR = 0 bar and URV = 10 bar.
   • Navigated: Device setup → Calibrate → PV rearrange → edited URV to 5 bar → pressed Send to write to instrument.
   • Returned the loop to auto and disconnected the HART communicator.

5. 5‑point calibration check

   • Applied pressures: 0.00, 1.25 (25%), 2.50 (50%), 3.75 (75%), 5.00 (100%) bar.
   • Technique:
     • Use coarse then fine adjust on the DPI; approach setpoints from below to minimize hysteresis.
     • Allow settling time (transmitter filtering can slow response).
   • Recorded mA readings (rounded to two decimals). Typical measured errors were around −0.01 to −0.02 mA.

6. Shutdown

   • Powered down equipment and removed connections; transmitter is ready for field use.

Error calculation and results

• Span = 20 mA − 4 mA = 16 mA
• Percent error = (mA error / 16 mA) × 100

• Example: a 0.01 mA error → (0.01 / 16) × 100 = 0.06% a 0.02 mA error → (0.02 / 16) × 100 = 0.13%

• These are very small errors and are within acceptable calibration limits shown in the tutorial.

Note: The HART communicator shows a star next to URV/LRV when changes are staged in the communicator but not yet written — you must press Send to commit the changes to the instrument.

Practical tips and notes

• Use PTFE tape on NPT threads to prevent leaks.
• Use a hydraulic pump for higher pressures (air is slow/inefficient for high pressures).
• Avoid overshooting setpoints and then coming back down; approach setpoints from below to reduce hysteresis effects.
• Use the fine adjust on the pressure source for precise setpoints.
• Allow time to settle because transmitter filtering can slow the response.
• The DPI could supply loop power, but the demo used the Fluke 789 for loop power and mA readout.

Devices/brands referenced

• Foxborough IG10P (pressure transmitter)
• Druck DPI 610 IS (pressure calibrator)
• Fluke 789 ProcessMeter (loop power and mA measurement)
• HART 475 field communicator (HART device configuration)

Main speaker / source

• Tutorial instructor / demonstrator (unnamed narrator in the video)
• Equipment manufacturers: Foxborough (transmitter), Druck (DPI 610), Fluke (789), and HART (475 communicator)