Emerson 6081-P instruction manual Calibration Slope and Offset

MODEL 6081-P pH/ORP	SECTION 10.0
	CALIBRATION – PH

During automatic calibration, the transmitter also measures noise and drift and does not accept calibration data until read- ings are stable. Calibration data will be accepted as soon as the pH reading is constant to within the factory-set limits of 0.02 pH units for 10 seconds. The stability settings can be changed.

In manual calibration, the user judges when pH readings are stable. He also has to look up the pH of the buffer at the temperature it is being used and enter the value in the transmitter.

Once the transmitter completes the calibration, it calculates the calibration slope and offset. The slope is reported as the slope at 25°C. Figure 10-1 defines the terms.

The transmitter can also be standardized. Standardization is the process of forcing the transmitter reading to match the reading from a second pH instrument. Standardization is sometimes called a one-point calibration.

FIGURE 10-1. Calibration Slope and Offset

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