Instruction manual

MODEL XMT-A-FF/FI SECTION 7.0

PROGRAMMING THE TRANSMITTER

8a. If you chose total chlorine, select single or dual slope calibration. For the vast

majority of applications, dual slope calibration is unnecessary.

8b. Enter the time constant for the input filter.

8c. To return to the main display, press MENU then EXIT.

9a. If you chose monochloramine, enter the time constant for the input filter.

9b. To return to the main display, press MENU then EXIT.

Cl Cal Slope?

Single

Dual

7.4 MAKING TEMPERATURE SETTINGS

7.4.1 Purpose

This section describes how to do the following:

1. Choose temperature units (°C or °F).

2. Choose automatic or manual temperature correction for membrane permeability.

3. Choose automatic or manual temperature compensation for pH (pH settings apply to free chlorine only).

4. Enter a temperature for manual temperature compensation.

7.4.2 Definitions — oxygen, ozone, chlorine, and monochloramine

1. AUTOMATIC TEMPERATURE CORRECTION. Membrane-covered amperometric sensors produce a current directly

proportional to the rate the analyte (the substance being measured) diffuses through the membrane. The diffusion

rate is proportional to the concentration of analyte and the temperature. As temperature increases, membrane per-

meability increases. Thus, an increase in temperature will cause the sensor current to increase even though the

analyte level remained constant. A correction equation in the transmitter software automatically corrects for changes

in membrane permeability. In automatic temperature correction, the transmitter uses the temperature measured by

the sensor for the correction.

2. MANUAL TEMPERATURE CORRECTION. In manual temperature correction the transmitter uses the temperature

entered by the user for the membrane permeability correction. It does not use the actual process temperature. Do

NOT use manual temperature correction unless the measurement and calibration temperatures differ by no more

than about 2°C. Manual temperature correction is useful only if the sensor temperature element has failed and a

replacement sensor is not available.

7.4.3 Definitions — pH

1. AUTOMATIC TEMPERATURE COMPENSATION. The transmitter uses a temperature-dependent factor to convert

measured cell voltage to pH. In automatic temperature compensation, the transmitter measures the temperature and

automatically calculates the correct conversion factor. For maximum accuracy, use automatic temperature compen-

sation.

2. MANUAL TEMPERATURE COMPENSATION. In manual temperature compensation, the transmitter converts meas-

ured voltage to pH using the temperature entered by the user. It does not use the actual process temperature. Do

NOT use manual temperature compensation unless the process temperature varies no more than about ±2°C or the

pH is between 6 and 8. Manual temperature compensation is useful if the sensor temperature element has failed

and a replacement sensor is not available.

Input filter?

63% in

05sec

Input filter?

63% in

05sec