PS-3220
Assembling the Titration Setup (See figure on next page)
13
013-16026A
Other Titrations
Titrations with different solutions can be performed using the same equipment and procedure. Other probes (such
as conductivity or ORP) can be used in place of the pH probe.
Theory of Operation
The Wireless Drop Counter uses an infrared light source and a photodetec
-
tor. Lenses spread the light into a “sheet” and refocus it onto the photode
-
tector. When a drop of fluid passes through the Wireless Drop Counter, it
partially blocks this sheet of light, and the photodetector registers a
momentary decrease in light intensity.
The Wireless Drop Counter uses infrared light and ignores visible light. On
power up, it automatically adjusts the light level for the best sensitivity. Use
the Wireless Drop Counter away from direct sunlight or other sources of
infrared that may interfere with it.
Troubleshooting the Sensor
•
If the sensor loses Bluetooth connection and will not reconnect, try cycling the ON button. Press and briefly
hold
the button until the status LEDs blink in sequence, and then release the button. Start the sensor in the
usual way.
•
If the sensor stops communicating with the computer software or tablet application, try restarting the software
or application. If the problem remains, press and
hold
the ON button on the sensor for 10 seconds and then
release. Start the sensor in the usual way.
•
On the computing device, turn Bluetooth off and then back on. Retry.
•
If the Wireless Drop Counter will not turn on, use the micro USB cable to connect it to a USB port or charger.
See the PASCO web site at www.pasco.com for more information.
Probe Care and Maintenance
The Wireless Drop Counter Sensor is splash resistant but not waterproof. Do not immerse the sensor in liquid. If
the inside surfaces of the rectangular drop window need to be cleaned, Use a piece of lens paper or a lint free cloth
and water or a glass cleaner.
Tips
•
Except for opening and closing the stopcocks, do not touch the syringe of the Drop Dispenser during the
titration; otherwise, the drop size may change significantly.
•
The drop rate must remain approximately constant (for example, about 2 drops per second) in order for the
drop size to remain constant.
•
Drop size depends on the exact position of the stopcock valves. Therefore, the average drop size will be
different for every titration. For each different titration, re-calibrate the sensor because the new titrant may have
different sized drops if it has a different density.
Problem
Cause
Solution
Indicator light flashes twice for a single
drop. Wireless Drop Counter registers
more drops than actually dispensed.
Fluid is splashing back into the drop
window.
Adjust the position of the beaker,
Wireless Drop Counter, or Drop
Dispenser to eliminate splash back
Indicator LED remains on constantly.
Wireless Drop Counter does not register
drops.
Lenses in drop window are dirty or
wet.
Clean lenses in the drop window with
water or a glass cleaner and dry with a
cotton swab or tissue.
detector
collimating
lens
focusing
lens
sheet of light
drop
infrared light
source
