Emerson manual Sensor Trim, Rosemount 3051N, Reference Manual, Device Setup, Microprocessor

Rosemount 3051N

FIGURE 2-7. Transmitter Data

Flow with Calibration Options.

Sensor

Signal

Sensor

Input

Pressure

Reference Manual

00809-0100-4808, Rev CA

June 2008

Transmitter Ranged 0 to 100 inH2O
Transmitter Electronics Module
Microprocessor
Digital PV
HART Communicator	Output Device	Analog Output
	20.00 mA
Input Device

3051:PT-4001

Online

1 ➡ Device Setup

2	PV	100.00 inH2O
3	AO	20.00 mA
4	LRV	0.00 inH2O
5	URV	100.00 inH2O

NOTE

Value on PV line should equal the input pressure. Value on AO line should equal the output device reading.

Deciding Which Trim Procedure to Use

Sensor Trim

To decide which trim procedure to use, you must first determine whether the analog-to-digital section or the digital-to-analog section of the transmitter electronics is in need of calibration. To do so, refer to Figure 2-7and perform the following procedure:

1.Connect a pressure source, a HART Communicator, and a digital readout device to the transmitter.

2.Establish communication between the transmitter and the communicator.

3.Apply pressure equal to the upper range point pressure (100 inH20, for example).

4.Compare the applied pressure to the Process Variable (PV) line on the Communicator On-line Menu. IF the PV reading on the communicator does not match the applied pressure, and you are confident that your test equipment is accurate, THEN perform a sensor trim.

5.Compare the Analog Output (AO) line on the communicator on-line menu to the digital readout device. IF the AO reading on the communicator does not match the digital readout device, and you are confident that your test equipment is accurate, THEN perform an output trim.

You can trim the sensor using either the full trim or the zero trim function. The trim functions vary in complexity, and their use is application-dependent. Both trim functions alter the transmitter’s interpretation of the input signal.

A zero trim is a single-point adjustment. It is useful for compensating for mounting position effects and is most effective when performed with the transmitter installed in its final mounting position. Since this correction maintains the slope of the characterization curve, it should not be used in place of a full trim over the full sensor range.

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