Emerson Rosemount 1056, Instruction Manual

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7.8 Calibration — Ozone
7.8.1 Description
An ozone sensor generates a current directly
proportional to the concentration of ozone in the sample.
Calibrating the sensor requires exposing it to a solution
containing no ozone (zero standard) and to a solution
containing a known amount of ozone (full-scale
standard). The Zero Calibration is necessary because
ozone sensors, even when no ozone is in the sample,
generate a small current called the residual or zero
current. The analyzer compensates for the residual
current by subtracting it from the measured current
before converting the result to an ozone value. New
sensors require zeroing before being placed in service,
and sensors should be zeroed whenever the electrolyte
solution is replaced. The best zero standard is deionized
water.
The purpose of the In Process Calibration is to establish
the slope of the calibration curve. Because stable ozone
standards do not exist, the sensor must be calibrated
against a test run on a grab sample of the process liquid.
Several manufacturers offer portable test kits for this
purpose. Observe the following precautions when taking
and testing the grab sample.
• Take the grab sample from a point as close to the sensor
as possible. Be sure that taking the sample does not
alter the flow of the sample to the sensor. It is best to
install the sample tap just downstream from the sensor.
• Ozone solutions are unstable. Run the test immedi-
ately after taking the sample. Try to calibrate the sensor
when the ozone concentration is at the upper end of the
normal operating range.
THIS SECTION DESCRIBES HOW TO CALIBRATE
THE MODEL 1056 WITH AN OzONE SENSOR. THE
FOLLOWING CALIBRATION ROUTINES ARE COV-
ERED.
Measure Ozone Sec. Calibration function: default value Description
7.8.2 Zero Cal Zeroing the sensor in solution with zero ozone
7.8.3
In Process Cal
Standardizing to a sample of known ozone concentration
A detailed flow diagram is provided at the end of Sec. 7 to guide you through the calibration routines.
TABLE 7- 10 Ozone Calibration Routines
To calibrate ozone:
1. Press the MENU button
2. Select Calibrate . Press ENTER.
3. Select Sensor 1 or Sensor 2 corresponding to
ozone. Press ENTER.
4. Select Ozone . Press ENTER.
The adjacent screen will appear. To calibrate Ozone or
Temperature, scroll to the desired item and press
ENTER.
S1: 1.234µS/cm 25.0ºC
S2: 12.34pH 25.0ºC
S N Calibrate?
Ozone
Temperature
Instruction Manual
LIQ-MAN-1056
Section 7.0: Calibration
April 2017