Skip to main content

Differential Pressure Transmitter Calibration Procedure

 Differential Pressure Transmitter Calibration Procedure

Calibration Procedure :

Set up the differential pressure transmitter, HART communicator, power supply, hand pump, and the multimeter as below (see below calibration setup Diagram).

Make sure the equalizing valve manifold is closed.

Apply a pressure to the transmitter equal to a lower range pressure (usually it correspond to 4 mA in the transmitter output). For example we have 0 to 100 mBar calibrated range, then the lower range pressure is 0, or let’s say we have -2 psig to 5 psig then we have lower range pressure equal to -2 psig.

Read the pressure in the transmitter LCD (or in the HART communicator). Adjust (if any) through the HART communicator so that the output of the transmitter (on LCD) is the same with the applied pressure.

Read the mA output of the transmitter by using a multimeter. Adjust (if any) through the HART communicator so that the output of the transmitter (on multimeter) is 4 mA.

Apply a pressure to the transmitter equal to an upper range pressure (usually it correspond to 20 mA in the transmitter output).

Read the pressure in the transmitter LCD (or in the HART communicator). Adjust (if any) through the HART communicator so that the output of the transmitter (on LCD) is the same with the applied pressure.

Read the mA output of the transmitter by using a multimeter. Adjust (if any) through the HART communicator so that the output of the transmitter (on multimeter) is 20 mA.


Set up the differential pressure transmitter, HART communicator, power supply, hand pump, and the multimeter as below (see below calibration setup Diagram).
Make sure the equalizing valve manifold is closed.
Apply a pressure to the transmitter equal to a lower range pressure (usually it correspond to 4 mA in the transmitter output). For example we have 0 to 100 mBar calibrated range, then the lower range pressure is 0, or let’s say we have -2 psig to 5 psig then we have lower range pressure equal to -2 psig.
Read the pressure in the transmitter LCD (or in the HART communicator). Adjust (if any) through the HART communicator so that the output of the transmitter (on LCD) is the same with the applied pressure.
Read the mA output of the transmitter by using a multimeter. Adjust (if any) through the HART communicator so that the output of the transmitter (on multimeter) is 4 mA.
Apply a pressure to the transmitter equal to an upper range pressure (usually it correspond to 20 mA in the transmitter output).
Read the pressure in the transmitter LCD (or in the HART communicator). Adjust (if any) through the HART communicator so that the output of the transmitter (on LCD) is the same with the applied pressure.
Read the mA output of the transmitter by using a multimeter. Adjust (if any) through the HART communicator so that the output of the transmitter (on multimeter) is 20 mA.
Typical tools required:
  • 24 VDC power supply
  • Multimeter digital
  • Pneumatic hand pump (up to 600 psig)
  • Hydraulic hand pump (up to 10.000 psig)
  • Low pressure hand pump
  • High precision digital test gauge
  • HART communicator
  • Screwdriver toolkit
 Note: point number 1, 2, 7, and 6 of the typical tools above can be replaced by a single multi-function calibrator available in the market.






Labels:

Comments

Post a Comment

Popular posts from this blog

Ferrules and Cross Ferruling

 Ferrules are identification labels provided for every wire terminations in an instrument, equipment, or electrical/instrumentation control panels. These tube-shaped sleeves can be inserted easily on each individual wire in a multi-core cable. In earlier days fixed digits/letters are used as ferrules, but now Instrumentation engineers/technicians prints out desired ferrules by using a ferrule printing machine. Typical Ferrule The numbers/ letters on the ferrules will be given as per the approved electrical hook up or loop diagrams. This helps technicians to easily identify a particular loop/wiring from a series of terminal blocks and to troubleshoot the desired terminal connection. Separate numbers on the ferrules distinguish the positive and negative polarities of wires, thus ensure the polarity protection of the instrument. Cross Ferruling  As a wire is connected on its both ends, it is quite useful to use a cross reference method for wire identification. Unlike normal ferru...
1 comment
Read more

What is a Torbar? – Averaging Pitot Tubes

 The Torbar is employed for flow measurement of liquids, gases, or steam in circular, square, or rectangular section ducts for large flow rates. The Torbar is an insertion type multi-port self-averaging primary sensor for flow measurement. Torbar TORBAR is a set of Pitot tubes mounted on a bar across the pipeline with no moving parts. An averaging Pitot tube is a technology, while TORBAR is a manufacturing brand name. There are several brands available in the market with VERABAR, ANNUBAR, etc. Averaging Pitot Tube Principle Purpose Averaging Pitot tube can be employed when the average velocity of the flow profile, rather than the velocity in a specific point in the cross-section is desired. Averaging Pitot Tubes Principle It measures the differential pressure between the static pressure tap and the tap of full pressure of a stream. Thus such magnitude of differential pressure is directly proportional to the square of the flow rate. Working The TORBAR is designed in such a way that ...
7 comments
Read more

Dissolved Oxygen Analyzer Working Principle

 What is dissolved oxygen ? Dissolved oxygen refers to oxygen dissolved in water. Its concentration is expressed as the amount of oxygen per unit volume and the unit is mg/L. Biologically, oxygen is an essential element for respiration of underwater life and also acts as a chemical oxidizer. The solubility of oxygen in water is affected by water temperature, salinity, barometric pressure, etc. and decreases as water temperature rises. Measurement of dissolved oxygen by the membrane electrode method The membrane electrode method measures a diffusion current or reduction current generated by the concentration of dissolved oxygen or partial pressure of oxygen to obtain the concentration of dissolved oxygen. This method is not affected by the pH value of water being measured, oxidation and reduction substances, color, turbidity, etc. and the measurement method offers good reproducibility. When a sensor is inserted into water, an air layer forms on the membrane (Teflon membrane). The ox...
1 comment
Read more