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ATI
Model Q45CT Portable Transmitter
Part 5
– Calibration
31
O&M Manual
Rev-G (7/15)
To begin the sensor zero cal, verify that the sensor is connected and clean and
dry. It should be held in the air with the electrodes at least 1 foot away from any
nearby objects.
Procedure
1. Scroll to the CAL menu section using the MENU key and press ENTER or the UP
arrow key.
Zero Cal
will then be displayed.
2. Press the ENTER key. The screen will automatically scroll through all ranges
and establish and store the proper zero points.
5.5
Temperature Calibration
The temperature input is factory calibrated for the highest accuracy.
Temperature calibration is not recommended; however, it is provided for
applications in which very long cable lengths are needed. For example, at 50
feet, readings may be off ±0.2 °C.
The temperature calibration sequence is essentially a 1-point offset calibration
that allows adjustments of approximately ±5 °C.
The sensor temperature may be calibrated on line, or the sensor can be removed
from the process and placed into a known solution temperature reference. In any
case, it is critical that the sensor be allowed to reach temperature equilibrium with
the solution in order to provide the highest accuracy. When moving the sensor
between widely different temperature conditions, it may be necessary to allow the
sensor to stabilize as much as one hour before the calibration sequence is
initiated. If the sensor is on-line, the user may want to set the output HOLD (see
Page 28) feature prior to calibration to lock out any output fluctuations.
Procedure
1. Scroll to the CAL menu section using the MENU key and press ENTER or the UP
arrow key.
2. Press the UP arrow key until
Cal Temp
is displayed.
3. Press the ENTER key. The message
Place sensor in solution then press
ENTER
will be displayed. Move the sensor into the calibration reference (if it
hasn’t been moved already) and wait for temperature equilibrium to be achieved.
Press ENTER to begin the calibration sequence.
4. The message
Adjust temp value then press ENTER
will be displayed, and the
right-most digit will begin to flash, indicating that the value can be modified.
Using the UP and LEFT arrow keys, modify the value to the known ref solution