YSI 95 User manual

Y
SI MODEL 95
Y
SI MODEL 95
Y
SI MODEL 95
Y
SI MODEL 95
Handheld
HandheldHandheld
Handheld
Dissolved Oxygen
Dissolved OxygenDissolved Oxygen
Dissolved Oxygen
A
nd
A
nd
A
nd
A
nd
Temperature System
Temperature SystemTemperature System
Temperature System
Operations
Manual

i
CONTENTS
CONTENTSCONTENTS
CONTENTS
SECTION 1 INTRODUCTION .........................................................................................................................................1
SECTION 2 PREPARING THE METER ........................................................................................................................2
2.1 UNPACKING.................................................................................................................................................................2
2.2 WARRANTY CARD ......................................................................................................................................................2
2.3 BATTERIES ..................................................................................................................................................................2
2.4 CALIBRATION/STORAGE CHAMBER ............................................................................................................................3
2.5 HAND STRAP...............................................................................................................................................................3
2.6 THE METER CASE .......................................................................................................................................................3
SECTION 3 PREPARING THE PROBE.........................................................................................................................4
3.1 CHOOSING THE RIGHT MEMBRANE CAP.....................................................................................................................4
3.2 MEMBRANE CAP INSTALLATION.................................................................................................................................4
SECTION 4 OPERATION .................................................................................................................................................6
4.1 TURNING THE INSTRUMENT ON.................................................................................................................................7
4.2 CALIBRATION ..............................................................................................................................................................7
4.3 MAKING MEASUREMENTS ..........................................................................................................................................8
4.4 STIRRING .....................................................................................................................................................................9
4.5 SAVING DATA..............................................................................................................................................................9
4.6 RECALLING STORED DATA..........................................................................................................................................9
4.7 ERASING STORED DATA............................................................................................................................................10
4.8 TOGGLING BETWEEN %-AIR SATURATION AND MG/L...............................................................................................11
4.9 DISSOLVED OXYGEN FILTER.....................................................................................................................................11
4.10 DISPLAY BACKLIGHT ..............................................................................................................................................11
SECTION 5 PRINCIPLES OF OPERATION.............................................................................................................12
5.1 MEA CLARK OXYGEN SENSOR................................................................................................................................12
5.2 DO READINGS FROM THE CATHODE REDUCTION.....................................................................................................13
5.3 FORMATION OF AGCL AT THE ANODE ......................................................................................................................13
5.4 FUNCTION OF THE ELECTROLYTE .............................................................................................................................13
SECTION 6 MAINTENANCE OF THE MEA SENSOR...........................................................................................14
6.1 ANODE SERVICE........................................................................................................................................................14
6.2 CATHODE SERVICE....................................................................................................................................................14
6.3 DISSOLVED OXYGEN PROBE PRECAUTIONS .............................................................................................................15
6.4 PROBE STORAGE .......................................................................................................................................................15
SECTION 7 DISCUSSION OF MEASUREMENT ERRORS...................................................................................16
SECTION 8 TROUBLESHOOTING............................................................................................................................17
SECTION 9 WARRANTY AND REPAIR...................................................................................................................19
APPENDIX A - GENERAL SPECIFICATIONS ..........................................................................................................24
APPENDIX B - REQUIRED NOTICE...........................................................................................................................26
APPENDIX C - ACCESSORIES AND REPLACEMENT PARTS ............................................................................27
APPENDIX D - UNIT CONVERSION...........................................................................................................................28
APPENDIX E - OXYGEN SOLUBILITY TABLE.......................................................................................................29
APPENDIX F - CALIBRATION VALUES TABLE.....................................................................................................31

ii

YSI Incorporated Model 95 1
SECTION 1
SECTION 1SECTION 1
SECTION 1 INTRODUCTION
INTRODUCTIONINTRODUCTION
INTRODUCTION
The YSI Model 95 Handheld Dissolved Oxygen and Temperature System is a rugged, micro-
processor based, digital meter with an attached YSI microelectrode array (MEA) dissolved oxygen
probe. The MEA sensor eliminates the need for stirring in most environmental applications
allowing measurement of DO in the field without an external stirring device. It also reduces
measurement errors caused by insufficient or inconsistent stirring.
The YSI Model 95 has the following features:
•Microprocessor control
•Minimal stirring dependence
•Low maintenance MEA DO probe
•Push-button calibration
•Cap membranes for easy membrane replacement
•Simultaneous display of temperature and DO in % air saturation or mg/L
•Automatic salinity compensation with manual entering of salinity value
•Automatic temperature compensation
•Data storage for 50 sets of readings with on screen recall
•Waterproof case (IP65)
The YSI Model 95 has a non-detachable, combination sensor available with cable lengths of 10, 25,
50 or 100 feet. The Model 95D has a detachable cable. The probe utilizes easy to install cap
membranes and the probe body has been manufactured with stainless steel to add rugged durability
and sinking weight. The silver anode of the MEA DO sensor requires no servicing for up to 10,000
hours (four years) of operation under normal operating conditions (no sulfite contamination).
The Model 95’s micro-processor allows the system to be easily calibrated with the press of a few
buttons. Additionally, the micro-processor performs a self-diagnostic routine each time the
instrument is turned on. The self-diagnostic routine provides useful information about the function
of the instrument and probe. For a list of these diagnostic codes, see Section 8, Troubleshooting.
A probe calibration/storage chamber is built into the instrument case. A small moist sponge in the
chamber provides a water-saturated air environment that is ideal for air calibration of the dissolved
oxygen probe. This chamber also provides a convenient place to store the probe when the system is
not in use. The Model 95 case is waterproof (rated to IP65) allowing operation in the rain without
damage to the instrument.
Six AA-sized alkaline batteries power the Model 95. A new set of alkaline batteries will provide
approximately 150 hours of continuous operation. When batteries need to be replaced, the LCD will
display a “LO BAT” message.
The YSI Model 95 is designed for use in environmental, aquaculture, and industrial applications
where accurate dissolved oxygen and temperature measurements are desired with minimal stirring.

YSI Incorporated Model 95 2
SECTION 2
SECTION 2SECTION 2
SECTION 2 PREPARING THE METER
PREPARING THE METERPREPARING THE METER
PREPARING THE METER
2.1
2.12.1
2.1 UNPACKING
UNPACKINGUNPACKING
UNPACKING
When you unpack your new YSI Model 95 Handheld Dissolved Oxygen and Temperature System
for the first time, compare the packing list with the contents of the shipping box. If there is anything
missing or damaged, call the dealer from whom you purchased the Model 95. If you do not know
which authorized dealers sold the system to you, call YSI Customer Service at 800-765-4974 or
937-767-7241, and we'll be happy to help you.
2.2
2.22.2
2.2 WARRANTY CARD
WARRANTY CARDWARRANTY CARD
WARRANTY CARD
Please complete the Warranty Card and return it to YSI. The warranty card allows the entry of your
purchase of this instrument in our computer system. Once your purchase is recorded, you will
receive prompt, efficient service if any part of your YSI Model 95 needs repair during the warranty
period.
2.3
2.32.3
2.3 BATTERIES
BATTERIESBATTERIES
BATTERIES
There are a few things you must do to prepare your YSI Model 95 for use. First, locate the six AA-
sized alkaline batteries that were included. Use a screwdriver or a small coin to remove the
thumbscrew on the bottom of the instrument (see figure below). This thumbscrew holds the battery-
chamber cover in place. The battery-chamber cover is marked with the words "OPEN" and
"CLOSE."
NOTE: On some models, the battery cover thumbscrew may be unscrewed by hand (a screwdriver
may not be required).
Hand strap
Polarity marking
Thumb screw
Battery chamber
cover
O-rings

Preparing the Meter Section 2
YSI Incorporated Model 95 3
There is a small molded insert inside each of the two battery-chamber sleeves. These labels
illustrate the correct way to install the batteries into each sleeve of the battery-chamber.
CAUTION: It is very important that the batteries be installed ONLY as illustrated. The instrument
will not function and may be damaged if the batteries are installed incorrectly.
Turn the instrument on by pressing and releasing the ON/OFF button on the front of the
instrument. The liquid crystal display (LCD) should come on. Allow a few seconds for the
instrument to complete its diagnostic routine. If the instrument does not operate, consult Section 8,
Troubleshooting.
You may also want to take the instrument into a dark room and with the instrument ON, hold down
the LIGHT button. The instrument back light should illuminate the LCD so that the display can be
easily read.
2.4
2.42.4
2.4 CALIBRATION/STORAGE CHAMBER
CALIBRATION/STORAGE CHAMBERCALIBRATION/STORAGE CHAMBER
CALIBRATION/STORAGE CHAMBER
The Model 95 has a convenient calibration/storage
chamber built into the instrument’s side. This chamber
provides an ideal storage area for the probe during
transport and extended non-use. If you look into the
chamber, you should notice a small round sponge in the
bottom. Carefully put about 10 drops of clean water into
the sponge. Turn the instrument over and allow any
excess water to drain out of the chamber. The wet
sponge creates a 100% water saturated air environment
for the probe that is ideal for dissolved oxygen
calibration.
2.5
2.52.5
2.5 HAND STRAP
HAND STRAPHAND STRAP
HAND STRAP
The hand strap (see figure on previous page) is designed to allow comfortable operation of the
Model 95 with minimum effort. If the hand strap is adjusted correctly, it is unlikely that the
instrument will be easily dropped or bumped from your hand.
To adjust the hand strap on the back of the meter, unsnap the vinyl cover and pull the two Velcro
strips apart. Place your hand between the meter and the strap and adjust the strap length so that your
hand is snugly held in place. Press the two Velcro strips back together and snap the vinyl cover
back into place.
2.6
2.62.6
2.6 METER CASE
METER CASEMETER CASE
METER CASE
The meter case is sealed at the factory and is not intended to be opened, except by authorized
service technicians. Do not attempt to separate the two halves of the meter case as this may
damage the instrument, break the water-proof seal, and may void the manufacturer's
warranty.
Figure 1

YSI Incorporated Model 95 4
SECTION 3
SECTION 3SECTION 3
SECTION 3 PREPARING THE PROBE
PREPARING THE PROBEPREPARING THE PROBE
PREPARING THE PROBE
The YSI Model 95 dissolved oxygen probe is shipped wet with a shipping membrane installed. This
protective membrane cap on the probe tip must be removed and replaced with a new membrane cap
filled with MEA probe solution before using the probe. Follow the instructions below to install the
new membrane cap.
3.1
3.13.1
3.1 CHOOSING THE CORRECT MEMBRANE CAP
CHOOSING THE CORRECT MEMBRANE CAPCHOOSING THE CORRECT MEMBRANE CAP
CHOOSING THE CORRECT MEMBRANE CAP
Two different membrane caps are available for the Model 95. The YSI Model 9501 Membrane Cap
Kit is supplied with the Model 95. This kit contains six 0.5 mil (.0005") membrane caps and a bottle
of MEA probe solution (KCl).
NOTE: YSI 9501 Membrane Caps offer the fastest response to changes in DO and are
recommended by YSI for most applications.
For conditions with low flow or stagnant water, a 1 mil (.001") membrane is available (YSI Model
9502 Membrane Cap Kit). This membrane requires less stirring than the 9501, but has a much
slower response. Use this membrane when minimal stirring (<2"/sec) is available.
3.2
3.23.2
3.2 MEMBRANE CAP INSTALLATION
MEMBRANE CAP INSTALLATIONMEMBRANE CAP INSTALLATION
MEMBRANE CAP INSTALLATION
WARNING: Use only YSI MEA probe solution in the membrane cap. Any other solution will
damage the MEA sensor.
To install a new membrane cap on your YSI Model 95 dissolved oxygen probe:
1. Unscrew and remove the probe sensor guard (see Figure 2 ).
2. Unscrew and remove the old membrane cap.
3. Thoroughly rinse the sensor tip with distilled water.
4. Hold the membrane cap and add 8 to 9 drops of MEA probe solution (about half full).
5. Tap the bottom of the cap with your finger a few times to remove any trapped air bubbles.
CAUTION: Do not touch the membrane surface.
6. Screw the membrane cap onto the probe tightly by hand (to prevent leakage of electrolyte). A
small amount of probe solution should overflow.
7. Shake off any excess probe solution and rinse the stainless steel thoroughly with distilled water
to prevent corrosion.

Preparing the Probe Section 3
YSI Incorporated Model 95 5
WARNING: Use only YSI MEA probe solution in the membrane cap. Any other solution will
damage the MEA sensor.
Figure 2
Unscrew cap
Unscrew guard
Fill new membrane
cap with 8-9 drops
of MEA probe
solution.
Tap cap with finger
to remove bubbles.
Screw guard on
tightly by hand
Screw cap on
tightly by hand

YSI Incorporated Model 95 6
SECTION 4
SECTION 4SECTION 4
SECTION 4 OPERATION
OPERATIONOPERATION
OPERATION
The following diagram is an overview of the operation of the Model 95. See the following sections
for details of operation.
Figure 3