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4.1.2 STAND
C
ARDIZE
ALIBRATION
A Standardize Calibration is a single point calibration where the transmitter's reading is adjusted to agree with a solution
of known value, either a calibration standard, a grab sample or laboratory determined value. In many cases the
constituents and the pressure and temperature of the process solution are very different from calibration solution. In
these cases, once the sensor has equilibrated, the Zero Point or Offset value may have shifted from the original
calibration point. Standardization allows for correction of this type of offset.
When the STAND key is pressed, the user is prompted to ENTER VALUE. The user enters the value they want the
transmitter to read and press OK. The user is then prompted to accept the value (YES/NO), and the calibration is
complete. Standardizations are single point calibrations.
At the end of each calibration, the Offset and Slope in the respective units: pH, mV, ppm, and mg/l.
4.1.3 MANUAL C
ALIBRATION
Manual calibration allows the user to enter calibration data for an electrode into the transmitter without performing a
calibration. A MANUAL Calibration requires the entry of three pieces of data, (1) A concentration with the (2)
corresponding mV value, and (3) a slope for the electrode. This allows laboratory generated calibration data for an
electrode to be entered in a remote analyzer where calibration is difficult or impractical.
Example: MANUAL Calibration for a pH electrode
1. Calibrate the pH electrode in the laboratory
2. Record the mV value of some pH Standard, pH 7.00 buffer = 6.8 mV (any pH – mV pair will work)
3. Calculate and Record the slope of the electrode, -58.2 mV/pH
4. Install the electrode into the field mounted sensor
5. Press MANUAL and enter the pH value, 7.00 pH, press mV, and enter the corresponding mV value, 6.8 mV, press
OK, Accept Offset?, press YES, enter slope – 58.2 mV/pH, press OK, Accept Slope?, Press YES
6. The Calibration is complete, the Offset and Slope values are displayed, press OK to exit.
– LQ800 T
4.2 C
ALIBRATION
The Model LQ800 transmitter provides three methods of calibration:
4.2.1 AUTO C
ALIBRATION
Auto Calibration is the primary calibration method for all measurements. AUTO calibration automatically recognizes the
calibration solution the sensor is in, and proposes the actual temperature compensated value for acceptance. AUTO
calibration can be a single or two point calibration. A single point calibration sets the zero point, or offset value, of the
sensor. The second calibration sets the slope of the sensor.
When the AUTO keys is pressed, the transmitter displays the PV (Process Variable) and the associated mV signal from
the sensor. When the reading has stabilized a calibration value is AUTOmatically proposed, i.e. 7.00 pH, 100 ppm
Fluoride ion, 0.00 mg/L Dissolved Oxygen. The user is prompted to accept the proposed calibration value or enter and
accept another value. Once Cal 1 is accepted, the user is asked to continue to Cal 2 (YES/NO). If yes, then a second
calibration value is proposed when the sensor has stabilizes in the second calibration solution. Accept the value and the
calibration is complete.
At the end of each calibration, the Offset and Slope are displayed in the respective units, pH, mV, ppm, mg/l.
HYDRA-DS NO
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