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The Rosemount 3051 transmitter is calibrated by the factory before leaving the premises. After installation, it is recommended to adjust the zero point of the instruments and differential pressure transmitters immediately in order to eliminate errors caused by the installation location or static pressure effects. Zero-point calibration can be performed using a field communicator or dedicated buttons. For instructions on using AMS, please refer to the Rosemount 3051 product manual (00809-0100-5007). Note: When performing zero-point calibration, ensure that the pressure equalizing valve is in the open position, and that all liquid connection branches are filled to the correct level. Select the calibration procedure: a. Analog zero-point calibration – set the analog output to 4mA. Also known as the “reset range,” it sets the lower range limit (LRV) to equal the measured pressure. . The display and digital HART output remain unchanged. b. Digital zero adjustment – Recalibrate the sensor’s zero point. .LRV is not affected. The pressure value will be zero (on the display screen and in the HART output). The 4mA point may not be zero. This requires that the zero pressure value calibrated at the factory be within a 3% URL range. Example: URV = 62.5 Kpa. The applied zero pressure value = +0.03*62.5 Kpa = +1.875 Kpa (compared to the factory setting); values outside this range will be rejected by the transmitter. Calibration using the field communicator 1. Connect the field communicator, make the wiring connections, and power it on. 2. Perform the required zero adjustment as indicated in the HART menu. Table 1. Zero-point calibration shortcut keys Figure 1. External configuration buttons Zero-point calibration can be performed through the following steps: Correction via LOI (option M4) 1. Set the transmitter pressure. 2. The operation menu is shown in the figure below. a. Perform zero-point correction via the Rerange option. b. Perform digital zero adjustment by selecting Zero Trim. Calibration using simulated zero point and range (Option D4): 1. Set the transmitter pressure. 2. Hold down the zero adjustment button for two seconds to perform analog zero calibration. Calibration using the digital zero point (option DZ): 1. Set the transmitter pressure. 2. Hold the zero adjustment button for two seconds to calibrate the digital zero point.