Calibration and Maintenance for the YSI Model 60 pH Meter

YSI ProDSS Meter Calibration and Maintenance
YSI ProDSS assembly & maintenance rev 6/1/16
These procedures are to be performed by program staff or people who have been trained by staff.
Table of Contents
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Putting the unit together
• Cable connection
• Pre-Sensor Installation
• Sensor installation
Maintenance
Short term storage
Long term storage
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YSI ProDSS Meter Calibration and Maintenance
A FEW NOTES BEFORE GETTING STARTED
The instrument/cable connectors, bulkhead ports, and sensor connector ends are not wetmateable and can become damaged if they come into contact with moisture. Never connect the
cable connector to the handheld unit, or install a sensor if they are wet! Carefully follow
sensor tightening instructions during installation. If any resistance is felt during any tightening
(sensor, sensor guard, port plug), stop tightening, loosen nut or guard, and start again.
PUTTING THE UNIT TOGETHER
Cable Connection
Make sure the connectors are clean and dry before connecting! If connecters are clean and
dry, align the keys on the male cable connector with the female slots on the instrument
connector. Push together firmly, and then twist the outer ring clockwise until it locks into place.
The metal pin should “snap” into place and be visible through the small hole in the outer ring
(see image below).
Metal pin showing through
outer ring of connector piece.
Sensor Installation
NOTE: There are two different storage procedures for the sensors and unit: short term (sensors
are still attached to the unit), and long term (sensors have been removed and individually
stored). If the unit has been stored under the short term procedures, continue to the Calibration
section below.
The ports on the ProDSS bulkhead are universal; therefore, you can install any sensor into any
port. For highest accuracy, always install a conductivity/temperature sensor to compensate all
measurement data for temperature and dissolved oxygen data for conductivity. Similar to the
cable connection, the sensor and bulkhead ports are not waterproof, therefore always make sure
the ports are clean and completely dry before installation. Any moisture in the ports will
result in damage to the unit not covered under its warranty. Avoid sensor installation in the
field at all costs.
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Dissolved Oxygen
1. Remove the DO sensor from the container. Slide the plastic protective cover off of the end
of the sensor; you may need to “wiggle” it back and forth to get it off.
NOTE: Do not remove the black DO cap (this cap will twist off in a counter clockwise
direction)!
2. Inside the plastic protective cover is a yellow sponge, inspect the sponge and take note if it
appears dry. Also inspect the tip of the sensor for fouling or other debris, if dirty clean with a
moist non-abrasive lint-free cloth.
NOTE: Clean the tip carefully to prevent scratches. Do not use organic solvents to clean the
ODO sensor or sensor cap.
3. Inspect the bulkhead ports for moisture or debris, clean with a dry lint-free cloth if need be.
If moisture can’t be reached with a cloth, ask staff to assist with an air compressor. Remove
the red connector cap and apply a thin coat of Krytox o-ring lubricant to the sensor o-rings
(maintenance kit). Wipe off any extra lubricant with a lint-free cloth (see image below).
4. Carefully align the sensor into the bulkhead port rotate the sensor gently until you can feel it
align with the bulkhead. Once aligned, push the sensor into the bulkhead until it is firmly
seated in the port (see image below).
5. Carefully tighten the retaining nut, if any resistance is felt loosen the nut and try again.
Finger tighten as much as you can, then use the sensor installation tool to tighten until snug
(see image below). DO NOT OVER TIGHTEN!
6. Submerge probe in water for 24 hours prior to calibrating.
Conductivity (NOTE: Use care when handling this sensor to prevent damage to the exposed
thermistor (at tip of sensor).
1. Remove the conductivity sensor from the container. Slide the clear plastic cap from the tip
of the sensor and store in container. Inspect the tip of the sensor for debris or fouling, look
into the two holes for debris or fouling. If the tip is dirty, refer to the Maintenance section
below for cleaning techniques.
2. Inspect the bulkhead ports for moisture or debris, clean with a dry lint-free cloth if need be.
If moisture can’t be reached with a cloth, ask staff to assist with an air compressor. Remove
the red connector cap and apply a thin coat of Krytox o-ring lubricant to the sensor o-rings
(maintenance kit). Wipe off any extra lubricant with a lint-free cloth (see image below).
3. Carefully align the sensor into the bulkhead port rotate the sensor gently until you can feel it
align with the bulkhead. Once aligned, push the sensor into the bulkhead until it is firmly
seated in the port (see image below).
4. Carefully tighten the retaining nut, if any resistance is felt loosen the nut and try again.
Finger tighten as much as you can, then use the sensor installation tool to tighten until snug
(see image below). DO NOT OVER TIGHTEN!
If not all ports on the bulkhead will be filled, a port plug must be installed to prevent damage to
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the unit.
pH
1. Remove the pH sensor from the container. Holding the bottle upright, remove the bottle
covering the tip of the sensor and replace the “open” cap and o-ring with the storage cap and
store in container. If the tip of the pH sensor appears dirty, refer to the Maintenance section
below for cleaning techniques.
2. Carefully rinse the sensor tip with clean tap or distilled water, TAKE EXTREME CARE to
not get the sensor connector end of the sensor wet. If you do get moisture in the connector
end, completely dry the sensor with a lint-free cloth, or ask staff for assistance with an air
compressor.
3. Inspect the bulkhead ports for moisture or debris, clean with a dry lint-free cloth if need be.
If moisture can’t be reached with a cloth, ask staff to assist with an air compressor. Remove
the red connector cap and apply a thin coat of Krytox o-ring lubricant to the sensor o-rings
(maintenance kit). Wipe off any extra lubricant with a lint-free cloth (see image below).
4. Carefully align the sensor into the bulkhead port rotate the sensor gently until you can feel it
align with the bulkhead. Once aligned, push the sensor into the bulkhead until it is firmly
seated in the port (see image below).
5. Carefully tighten the retaining nut, if any resistance is felt loosen the nut and try again.
Finger tighten as much as you can, then use the sensor installation tool to tighten until snug
(see image below). DO NOT OVER TIGHTEN!
Turbidity
1. Remove the turbidity sensor from the container. Slide the clear plastic cap from the tip of the
sensor and store in container (you may need to wiggle it off).
2. If the tip is dirty, refer to the Maintenance section below for cleaning techniques.
3. Inspect the bulkhead ports for moisture or debris, clean with a dry lint-free cloth if need be.
Remove the red connector cap and apply a thin coat of Krytox o-ring lubricant to the sensor
o-rings. Wipe off any extra lubricant with a lint-free cloth
4. Carefully align the sensor into the bulkhead port, rotate the sensor gently until you can feel it
align with the bulkhead. Once aligned, push the sensor into the bulkhead until it is firmly
seated in the port.
5. Carefully tighten the retaining nut, if any resistance is felt loosen the nut and try again.
Finger tighten as much as you can, then use the sensor installation tool to finish tightening.
You will not need to tighten the retaining nut much more, only a ¼ to ½ turn, DO NOT over
tighten.
If not all ports on the bulkhead will be filled, a port plug must be installed to prevent damage to
the unit.
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YSI ProDSS Meter Calibration and Maintenance
Installing the Sensor Guard
1. Carefully slide the sensor guard over the bulkhead and attached sensors/port
plugs. Push the sensor guard toward the bulkhead until the sensor guard
threads align with the bulkhead threads (see image right).
2. Carefully finger-tighten the sensor guard clockwise.
NOTICE: If any resistance is felt, loosen the sensor guard completely to prevent
cross-threading. Incorrect installation may cause damage to the sensor guard or
bulkhead that is not covered by the warranty.
Battery Life
Use YSI designated charging equipment only!
If the battery is not charged, the meter must be charged from the AC power
adapter (strongest charge source), directly from a computer USB connection or
from an external, portable USB battery pack. For the instrument to recognize
that it is using AC power, you must start charging the ProDSS while on. After
the instrument recognizes it is being charged, it can be turned off to finish
charging. When using the AC adapter, it takes approximately 14 hours to charge
the ProDSS battery when the instrument is turned off during the charge. The
amount of time required to completely charge the battery pack when the ProDSS
is initially turned on during the charge is approximately 9 hours. Expected battery life:
• ProDSS instrument only - 48 hours
• ProDSS with fully loaded cable assembly and
25% (Default) LCD brightness - 20 hours
• ProDSS with fully loaded cable assembly and 100% LCD brightness - 14 hours
For maximum battery life, keep the battery 40% to 80% charged. Also, a larger
discharge (e.g. to 50%) is better than a small discharge (e.g. to 90%) between recharges.
Check Sensor Readings
After installing all the sensors turn the unit on. In the “Run”
screen (main display screen, image right) make sure all
parameters are being displayed and are displaying the
proper units:
temperature – °C
barometer – inHg
dissolved oxygen – DO mg/L
conductivity – SPC-µS/cm
salinity – SAL-ppt
pH – pH units
turbidity – FNU
If any of these are not right, do the following:
Select the probe button
and scroll down to Display
submenu and hit enter. Scroll down and select the desired
parameter. A submenu will appear with multiple unit
options, select the proper unit and return to the Run Screen.
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YSI ProDSS Meter Calibration and Maintenance
MAINTENANCE
When performing maintenance on the ProDSS and its sensors, follow the specified procedures in
this section, which have been taken directly out of the manual, or it could void the warranty. For
more information on the warranty, consult the manual.
Cleaning the Handheld Unit, Cable, and Bulkhead
The handheld unit, consisting of the screen, keypad, and the unit itself, can be cleaned with a
wash cloth dampened with a mild solution of clean water and dish soap.
DO NOT clean handheld unit, cable, or bulkhead if they are detached or the sensor ports are
exposed (on bulkhead). If these connectors are exposed to any moisture the unit can be damaged
and would not be covered under warranty.
Cleaning the Sensor Guard
For a quick cleaning of the sensor guard, use a cloth
dampened with clean water and dish soap. To remove
resistant dirt or heavy bio-fouling, soak the guard in a
solution of clean water and dish soap and then scrub with a
plastic scrub brush. For a stronger soak, use vinegar.
DO NOT use a brush that could scratch the finish on the
guard, DO NOT sand or polish the guard. Removal of the
guard coating can affect turbidity data.
Cleaning the Bulkhead & Probes—general instructions
The bulkhead, probe guard, and calibration cup can all be cleaned with a mild
detergent. A bottle brush works well for cleaning the calibration cup; remove the
locking ring and gasket and scrub the inside of the chamber well. Remove the
bottom of the cup to clean it as well, particularly the threads which can get full of
grit. Use a bottle brush to clean the probe guard, removing it from the bulkhead
and unscrewing the bottom of the guard to clean it. Clean any dirt off of the
bulkhead and sides of the probes using a toothbrush. Don’t scrub the faces of
the probes with a brush, as this could cause damage. Be sure to rinse
everything well with tap water after you’ve cleaned it.
Cleaning the Insides of the Sensor Ports
First clean and dry around the bases of the sensors, preferably with forced air. Use the sensor
ring wrench to detach the sensors from their ports. There are two o-rings on every probe that
keep water out of the ports. Look for damage or sediment on these o-rings, in which case the
seal could have been compromised—report this to YSI. If you see any sediment or
contamination, wipe the o-rings with a Kimwipe and apply a thin layer of Krytox grease. You
can also flush it out with isopropyl alcohol to dry it completely (can use forced air) and remove
any contamination that might be present. Tiny drops of water inside the port probably will not
do any damage to the cable assembly.
Conductivity Sensor
NOTE: Be careful when handling this sensor, the tip has a temperature sensor that is fragile.
1. Dip the cleaning brush from the maintenance kit in distilled or clean tap water, insert the
brush at the top of the channels and sweep the brush back and forth 15-20 times.
2. If heavy build up has occurred on the electrodes, use a mild solution of dish soap and clean
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water. If build up is still present, soak the sensor in white vinegar and then clean with the
brush and a mild soap and water solution.
3. Rinse the sensor after cleaning.
4. Gently pat dry with Kimwipes and proceed to the Storage section below.
pH Sensor
NOTE: pH and pH/ORP sensors require periodic maintenance to clear contamination from the
sensing elements. These contaminants can slow sensor response time. Clean the sensors when
deposits, bio-fouling or other contamination appears on the glass or when the sensor response
time is noticeably slow. Try to avoid using deionized water when cleaning or storing (short
term) the pH sensor, clean tap water will suffice.
DO NOT physically scrub or swab the glass bulb, the bulbs are fragile and can break with a
small amount of force.
1. Remove the sensor from the bulkhead and soak the end of the sensor in a mild solution of
clean tap water and dish soap in a glass beaker. Soak for ~10 to 15 minutes.
2. After soaking, rinse with clean tap water and inspect the glass probe, if the probe is visibly
clean then proceed to storage.
3. If the glass bulb appears to still be dirty, soak the sensor in 1 molar HCl for 30 to 60 minutes,
if HCl is not available, use white vinegar. After soaking in HCl rinse with clean tap water,
then soak the sensor in clean tap water for 60 minutes, stir occasionally.
4. If dirt or bio-fouling is still present, soak the sensor in a 1:1 dilution of clean tap water and
chlorine bleach for 60 minutes. Rinse the sensor with clean tap water; soak the sensor in
clean tap water for 60 minutes.
5. Gently pat dry with Kimwipes and proceed to the Storage section below.
Turbidity Sensor
Clean the sensing window with a non-abrasive, lint-free cloth. Clean the window carefully to
avoid scratches. If necessary, use a mild solution of dish soap and water. Gently pat dry with
Kimwipes and proceed to the Storage section below.
Dissolved Oxygen Sensor
ODO sensor caps are warranted for 1 year but have a typical working life of 18 to 24
months. As the ODO sensor caps ages, large scratches in the paint/dye layer and changes in the
dye layer can reduce measurement stability and response time. Periodically inspect the sensor
cap for damage and large scratches in the paint/dye layer. Replace the cap when readings become
unstable and cleaning the cap and DO recalibration do not remedy the symptoms.
The sensor cap should be kept clean since some types of fouling may consume oxygen
which could affect the dissolved oxygen measurements. To clean the sensor cap, gently wipe
away any fouling with a lens cleaning tissue that has been moistened with water.
NOTICE: Do not use organic solvents to clean the sensor cap. Using an organic solvent to clean
the sensor cap may cause permanent damage to the cap. For example, alcohol will dissolve the
outer paint layer and other organic solvents will likely dissolve the dye in the cap.
Sensor Cap Replacement
YSI recommends replacing the sensor cap once a year, but can last up to 2. It is VERY
important to keep the instruction sheet that is shipped with the new sensor and cap, or a new
replacement cap. Calibration coefficients are on the instruction sheet and must be loaded onto
the ProDSS; keep the coefficients in case you need to reload them into the ProDSS.
It is also important to keep the sensor cap in a 100% humid environment, the storage sections
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below instruct on how to keep the sensor under these conditions. If receiving a new cap, do not
remove it from its shipping chamber until ready for installation.
Replacing the DO Sensor Cap
NOTE: Use extreme care to not damage the threads at the end of the sensor
1. Turn the old cap on the sensor counterclockwise and remove, do not use any hand tools to
remove this cap as it could damage the sensor threads. If cap cannot be removed without a
hand tool, a small pair of pliers can be used with care until the cap “breaks loose”. Never use
the pliers on the sensor itself.
2. Remove and discard the old o-ring without using any tools, clean the threads with a clean
lint-free cloth.
3. Inspect the new o-ring for any nicks, tears, or particles/contaminants. If the o-ring is
compromised, discard and get a new one from the maintenance kit.
4. Install the new o-ring over the threads and into the o-ring groove, DO NOT twist the o-ring.
5. Skillfully apply a thin coat of Krytox to the o-ring only, if excess lubricant is applied to the
threads or sensor body, gently wipe it off with a lint-free cloth.
6. Make sure the new sensor cap cavity is completely dry, then carefully finger-tighten the cap
clockwise onto the sensor. The o-ring should be compressed between the sensor cap and
body and not pinched. If the o-ring is pinched, discard and repeat the above steps with a new
o-ring. Do not over tighten the cap.
After the new sensor cap has been successfully installed, the sensor cap coefficients must be
updated on the ProDSS unit. You will need the instruction sheet that was shipped with the new
sensor cap. Attach the sensor to the bulkhead; refer to the Sensor Installation section above for
proper sensor installation techniques.
Updating the ODO Sensor Cap Coefficients:
1. Select the probe button
, then Setup, then ODO, then Sensor Cap Coefficients
2. Using the coefficient values from the instruction sheet, enter the coefficient # into the proper
coefficient slot in the handheld. After all the coefficients have been entered, select Update
Sensor Cap Coefficient.
3. Hit Yes on the prompt screen to override the old coefficient #s.
• After updating the Coefficients, the Serial # in the Sensor Cap menu will be updated
automatically based on your entries. If errors are made in entering the Sensor Cap
Coefficients, the instrument will block the update and an error message will appear on the
display.
• If you see this error message, re-enter the coefficients and check them carefully for correct
transcription from the Calibration Code Label prior to selecting Update Sensor Cap
Coefficients.
• If you receive an error message after several entry attempts, contact YSI Technical Support
for assistance (1-800-765-4974).
• Calibrate the sensor after cap replacement and coefficient update; refer to the DO
Calibration section above.
• IF THE CAP EVER GETS DRIED OUT (left dry for longer than 8 hours), rehydrate the
cap by soaking it in room temperature tap water for 24 hours. After the soak, recalibration
the sensor.
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Installing a Port Plug
1. Apply a thin coat of Krytox o-ring lubricant to the o-rings on the plug port.
2. Remove any excess lubricant from the o-rings and port plug with a lint-free cloth.
3. Insert the port plug into the empty port and press until firmly seated.
4. Finger-tighten the port plug clockwise to install. If necessary, use the sensor installation tool
to make sure that the plug is fully seated into the port.
NOTICE: The o-rings will not be visible if a port plug is correctly installed. Do not overtighten the port plug. Over-tightening can cause damage
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YSI ProDSS Meter Calibration and Maintenance
SENSOR STORAGE
There are two ways to store the YSI ProDSS: short term, and long term. Only use the Short Term
Storage procedures if the unit and its sensors will be stored for 4 weeks or less. If the unit will be
stored for over a month, use the Long Term Storage procedures described below.
Short Term Storage – Storage time ≤ 4 weeks
When in regular field use or for the duration of the monitoring quarter, all sensors should remain
installed on the bulkhead. All sensors should remain in a water-saturated air environment (this
especially applies to the DO sensor cap) except for turbidity, which can be stored in a dry
environment if stored separate. However, for ease of use and to reduce damage to sensors during
removal, keep all sensors on the bulkhead and in a water-saturated air environment during short term
storage.
• Place approximately 0.5 in (1 cm) of any water (deionized, distilled or environmental) in
calibration cup. Install the calibration cup on the bulkhead and firmly tighten to prevent
evaporation.
• If storing for longer than a week but < 4 weeks, use expired pH 4 buffer as a storage solution
to improve the life of the pH probe. Pour enough pH 4 buffer in the calibration cup so the
ends of the sensor modules are all submerged when the sensor assembly is oriented with the
sensor ends down. Store the unit in this orientation.
Long Term Storage – Storage time > 4 weeks
At the end of each monitoring session, the ProDSS should be broken down so that the individual
sensors can be stored more securely and under their own individual proper storing conditions.
Storage caps can be found in the individual storage boxes of each sensor, do not lose these caps.
The following are a few guidelines to removing and storing the sensors:
1. Remove and store each sensor individually, do not remove them all at once and then store each
sensor. This can cause situations where the sensors are not secure and could be dropped and
damaged.
2. Make sure each sensor is clean and/or dry before long term storage. Se the Maintenance section
above for proper cleaning/drying techniques.
3. Always be aware of the sensor connector ends, and the bulkhead ports. DO NOT get water into
these connectors, if you do always dry before connecting or turning on the instrument. Get help
from staff if you get a connector end wet.
4. Confirm via the post check sheet that all parameters on the ProDSS have undergone their post
check procedures after a monitoring session. If a parameter has not undergone post check,
inform the staff.
Conductivity
1. Loosen the retaining nut on the sensor using the removal tool, use fingers to finish removing the
retaining nut from the bulkhead.
2. Remove the sensor from the bulkhead. Inspect the tip for dirt or debris, if it warrants cleaning,
see the Maintenance section above for proper cleaning techniques. Take care to not get the
exposed sensor connector end wet.
3. Pat the sensor dry with Kimwipes or a lint-free, non-abrasive cloth.
4. Place the red cap onto the sensor connector end.
5. Place the sensor into its designated long term storage container.
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Turbidity
1. Loosen the retaining nut on the sensor using the removal tool, use fingers to finish removing the
retaining nut from the bulkhead.
2. Remove the sensor from the bulkhead. Inspect the tip for dirt or debris, if it warrants cleaning,
see the Maintenance section above for proper cleaning techniques. Take care to not get the
exposed sensor connector end wet.
3. Pat the sensor dry with Kimwipes or a lint-free, non-abrasive cloth.
4. Place the red cap onto the sensor connector end.
5. Place the clear plastic cap onto the end of the sensor.
6. Place the sensor into its designated long term storage container.
pH
1. Loosen the retaining nut on the sensor using the removal tool, use fingers to finish removing the
retaining nut from the bulkhead.
2. Remove the sensor from the bulkhead. Inspect the tip for dirt or debris, if it warrants cleaning,
see the Maintenance section above for proper cleaning techniques. Take care to not get the
exposed sensor connector end wet.
3. Pat the sensor dry with Kimwipes only.
4. Place the red cap onto the sensor connector end.
5. Take out the storage bottle, “open” lid and o-ring from the storage box.
6. Carefully slide the “open” lid with the o-ring placed inside the lid onto the sensor until it is about
1” up the sensor.
7. Remove the storage cap on the storage bottle. Place the tip of the sensor into the bottle and
screw the “open” lid onto the bottle so that the sensor tip is submerged in the buffer 4 solution.
Do not let the sensor tip touch the bottom of the bottle.
8. Place the sensor and the storage cap into its designated long term storage container.
Dissolved Oxygen
1. Loosen the retaining nut on the sensor using the removal tool, use fingers to finish removing the
retaining nut from the bulkhead.
2. Remove the sensor from the bulkhead. Inspect the tip for dirt or debris, if it warrants cleaning,
see the Maintenance section above for proper cleaning techniques. Take care to not get the
exposed sensor connector end wet.
3. Pat the sensor dry with Kimwipes or a lint-free, non-abrasive cloth.
4. Place the red cap onto the sensor connector end.
5. Wet the yellow sponge located in the plastic cap, do not soak the sponge, just wet it until it
becomes moist but is not dripping water.
6. Place the plastic cap with the sponge in it over the sensor tip.
7. Place the sensor into its designated long term storage container.
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