YSI 5000 User manual

YSI MODEL 5000
YSI MODEL 5100
Dissolved Oxygen
Temperature
SERVICE MANUAL

i
TABLE OF CONTENTS
Section 1 General Description..................................................................................................... 1
Section 2 Specifications................................................................................................................ 2
Section 3 Software Flow Chart.................................................................................................... 3
Section 4 Setup.............................................................................................................................. 4
4.1 Display Setup.................................................................................................................... 4
4.2 Report Setup.....................................................................................................................6
4.3 Autostable Setup .............................................................................................................. 7
4.4 System Setup..................................................................................................................... 8
Section 5 Calibration.................................................................................................................. 10
5.1 Dissolved Oxygen Calibration.......................................................................................10
Auto Cal........................................................................................................................... 10
DO Cal (manual).............................................................................................................11
5.2 Barometer....................................................................................................................... 13
5.3 Salinity............................................................................................................................. 13
5.4 Zero Calibration............................................................................................................. 14
Section 6 Diagnostics.................................................................................................................. 15
6.1 History............................................................................................................................. 15
6.2 Sensor.............................................................................................................................. 16
6.3 Reset Ps ........................................................................................................................... 16
Section 7 Troubleshooting Chart .............................................................................................. 17
Section 8 Test Procedure............................................................................................................ 19
Section 9 Maintenance................................................................................................................ 21
9.1 5000 and 5100 Instruments ........................................................................................... 21
Batteries........................................................................................................................... 21
9.2 5910 and 5905 Dissolved Oxygen Probes..................................................................... 22
Electrode Cleaning .........................................................................................................22
Section 10 Software Upgrade Procedure.................................................................................. 23
Section 11 Disassembly/Assembly Procedures......................................................................... 25
Section 12 Circuit Description................................................................................................... 26
Section 13 Schematic Diagrams ................................................................................................30
Section 14 PC Board Layout...................................................................................................... 37
Section 15 PC Board Components............................................................................................ 39
Section 16 Accessories and Replacement Parts ....................................................................... 40
Section 17 Warranty and Repair .............................................................................................. 41

ii

YSI Incorporated Model 5000/5100 Service Manual 1
SECTION 1 GENERAL DESCRIPTION
MODEL 5000 FEATURES
The Model 5000 is a microprocessor based, menu-driven, dissolved oxygen meter designed to
perform laboratory measurement of dissolved oxygen and Biochemical Oxygen Demand (BOD).
The angled profile makes these instruments both functional and attractive. A large graphical
display provides on-screen menus, and large data fields for ease of operation and readability. The
angle and position of the keypad make operation of the 5000 comfortable. The tactile and audio
response from each key stroke give you the confidence that every command has been received.
The Model 5000 is compatible with all existing YSI dissolved oxygen probes when used with the
YSI Model 5011 adapter. The new YSI Model 5010 self-stirring BOD Probe allows you to
operate the probe from the instrument’s power supply, eliminating the need for a separate power
cable for the probe.
Internal memory for storing up to 100 sets of data, and an RS232 port allow you to upload data
from the Model 5000 directly to your computer. Or you can use your Model 5000 with YSI BOD
Analyst software.
MODEL 5100 FEATURES
The YSI Model 5100 has all of the same functionality of the Model 5000 plus many automated
and application specific features.
The YSI 5100 is the first DO instrument to offer built-in application software for the calculation
of Oxygen Uptake Rate (OUR) and Specific Oxygen Uptake Rate (SOUR). These application
features simplify compliance with USEPA 503 regulations for vector attraction and provide
useful tools for plant operation decisions.
For laboratories with larger volumes, the Model 5100 offers bar code scanner and BOD Analyst
software capability. These tools greatly reduce the labor required for processing BODs and
calculating BOD values. The RS232 serial port makes it easy to capture data electronically.
The model 5000 and 5100 software can be upgraded easily using your computer. When YSI
upgrades these instruments, you’ll be able to get a floppy disk from YSI and simply upgrade the
software in a few minutes.
Calibration of the Model 5100 has been greatly simplified when compared to other dissolved
oxygen instruments. With it’s internal barometer, the Model 5100 is able to automatically
compensate for changes in barometric pressure so there is no need for charts, altitude information
or external barometric pressure information.

YSI Incorporated Model 5000/5100 Service Manual 2
SECTION 2 SPECIFICATIONS
OXYGEN MEASUREMENT
Ranges: mg/L: 0.0 to 60.0 mg/L
% air saturation: 0.0 to 600.0% air saturation
mbar: 0.0 to 1500
Accuracy: mg/L: ±0.1% plus 1 Least Significant Digit (LSD)
% air saturation: ±0.1% plus 1 LSD
mbar: ±1% plus 1 LSD
Resolution: mg/L: 0.1%, or 0.01 mg/L , whichever is greater
% air saturation: 0.1% air saturation
mbar: 1 mbar
TEMPERATURE MEASUREMENT
Range: -5.0 to +50.0°C
Accuracy: ±0.1°C
Resolution: 0.01°C
BAROMETRIC PRESSURE MEASUREMENT
Range: 450 to 825 mmHg (600 to 1100 mbar)
Accuracy: ±1% plus 1 LSD within ±10°C ambient temperature from calibration point
Resolution: 1 mmHg
TEMPERATURE COMPENSATION
The mg/L mode is automatically temperature-compensated to an accuracy of ±1% of DO
readings between 0 and 5°C, and to an accuracy of ±0.6% of readings between 5 and 45°C.
The % air saturation mode is automatically temperature-compensated to an accuracy of ±0.5% of
calibration values between 0 and 5°C, and to an accuracy of ±0.3% of values between 5 and
45°C.
SALINITY COMPENSATION
Range: 0.0 to 40.0 ppt
Accuracy: ±.02 mg/L
OPERATING ENVIRONMENT
0 to 45°C, 10 to 90% relative humidity, non-condensing
WATER RESISTANCE
The Model 5000 and 5100 are designed exclusively for indoor use and are NOT waterproof.
POWER
The Model 5000 & 5100 are powered by an AC adapter or 4 C-size alkaline batteries. A new set
of alkaline batteries will power the selected instrument for approximately 30 hours (not including
stirring).

YSI Incorporated Model 5000/5100 Service Manual 3
SECTION 3 SOFTWARE FLOW CHART
The following section shows the software flow chart for the 5000/5100. The two operating
modes, Main and Application, are shown at the top with the soft-key functions that are accessed
in each mode below them. Functions in shaded boxes are only available on the model 5100.
MAIN
Store
Reveiw
Clear
Send
CALIBRATE
Auto Cal
DO Cal
SETUP
Display
Report
Stable
System
APPLICATION
OUR
SOUR
Remote
Print All
Delete All
Size
Unit
Contrast
Last Digit
SDF
CDF
Range
Next
Audio On/Off
Time/Date
Version
RS-232
Start
Setup
End
Print on/off
Start
Setup
End
Print on/off
Skip
Up
Down
Confirm
DIAGNOSIS
Recall
Print on/off
Print All
Print on/off
Print All

YSI Incorporated Model 5000/5100 Service Manual 4
SECTION 4 SETUP
From Main mode, press the [CALIBRATE] soft-key to enter the calibration menu. Notice that
the dark bar in the top right corner of the display shows the current mode.
98.0 % 8.15 mg/L Calibrate
0.0 ppt 740
mmHg
24.38°C 11:33AM
AUTO CAL DO CAL SETUP DIAGNOSTICS
Next, press the [SETUP] soft-key to enter the Setup menu. The bottom row of the display will
show the following soft-key setup selections.
8.15*
mg
/L
24.38°C 11:33AM
DISPLAY REPORT STABLE SYSTEM
These four selections are used to change the instrument setup.
4.1 DISPLAY SETUP
Press the [DISPLAY] soft-key to show the following menu.
8.15*
mg
/L
24.38°C 11:33AM
SIZE UNITS CONTRAST LAST DIG.
The [SIZE] soft-key cycles among the two possible display arrangements for Main mode. One
selection shows as many parameters as possible, the other shows Dissolved Oxygen in large type
with temperature and time in small type.
Setup
Display

YSI Incorporated Model 5000/5100 Service Manual 5
98.0% 8.15
mg/L Display
0.0 ppt 740
mmHg
24.38°C 11:33AM
SIZE UNITS CONTRAST LAST DIG.
The [UNITS] soft-key changes the display unit(s) of Dissolved Oxygen. When you have selected
a large size display, the DO number cycles among the three possibilities, percent, milligrams per
liter and millibars.
92.2*%
24.38°C 11:33AM
SIZE UNITS CONTRAST LAST DIG.
If the small size display has been selected, the dual DO display cycles among the three
possibilities, percent and milligrams per liter, milligrams per liter and millibars or percent and
millibars. An example is shown below.
8.71 mg/L 208
mbar Display
0.0 ppt 740
mmHg
24.38°C 11:33AM
SIZE UNITS CONTRAST LAST DIG.
The [CONTRAST] soft-key allows the user to change the display contrast. The display contrast
will change slightly each time the [UP] or [DOWN] soft-key is pressed.
The [LAST DIG.] soft-key allows the user to suppress the last digit of the DO reading.
8.2*
mg
/L
24.38°C 11:33AM
SIZE UNITS CONTRAST LAST DIG.
Press the [MODE] key to return to the Setup menu. If you wish to return to Main mode, press
[MODE] two more times.
Display
Display

YSI Incorporated Model 5000/5100 Service Manual 6
4.2 REPORT SETUP
From the Setup menu, press [REPORT] to display the following soft-keys.
[SDF] Space Delimited Format Report
[
*
]
SAMPLE ID #
[
*
]
DATE
[
*
]
DO%
[
*
]
TIME
[
*
]
DO m
g
/L
[
*
]
BAROMETER
[
*
]
TEMPERATURE
[
*
]
SALINITY
PRINT Record from
[
0
]
to
[
99
]
SDF CDF RANGE NEXT
The display lists the parameters that can be included in the output string at the RS232 serial port,
the default set has everything selected for inclusion.
You can select the report format that you wish to use by pressing the [SDF] or [CDF] soft-key.
Select [SDF] for Space Delimited Format (standard text). If you are going to import the data to a
spreadsheet, select [CDF] for Comma Delimited Format.
The asterisk character in front of each parameter indicates that the parameter will be included in
the report. Press the [NEXT] soft-key to select the parameter that you want to change. Then press
[ENTER] to turn the asterisk character on or off.
NOTE: After pressing [SDF] or [CDF] to choose the report format, press the [MODE] key to
exit the Report menu. Do NOT press [ENTER] as this will change the currently selected
parameter.
To return to Main mode, press [MODE] two more times.
The [RANGE] soft-key brings up the following soft-key menu.
[SDF] Space Delimited Format Report
[
*
]
SAMPLE ID #
[
*
]
DATE
[
*
]
DO%
[
*
]
TIME
[
*
]
DO m
g
/L
[
*
]
BAROMETER
[
*
]
TEMPERATURE
[
*
]
SALINITY
PRINT Record from
[
00
]
to
[
99
]
UP DOWN DIGIT NEXT
This menu allows specifying a specific range of memory locations for the report. The default
range is 00 - 99 and empty locations will not be sent to a computer or serial printer.
The display digit that has the flashing cursor below it is increased or decreased by pressing the
[UP] or [DOWN] soft-key. If the [UP] or [DOWN] soft-key is held down, the digit will continue
to change until the key is released. The [DIGIT] soft-key makes it easy to make large changes by
selecting the digit you wish to change. Press the [NEXT] soft-key to change between the
minimum and maximum parameter. When the desired number is obtained, pressing [ENTER]
will accept the number and exit the RANGE sub-menu.
To return to Main mode, press [MODE] three more times.
Flashing Cursor

YSI Incorporated Model 5000/5100 Service Manual 7
4.3 AUTOSTABLE SETUP
The autostable feature indicates when readings are stable by emitting a single beep and
displaying an asterisk (*) to the right of the dissolved oxygen reading. The instrument uses
criteria that you input to determine what a stable reading is. You select the maximum percent of
change that may occur during a selected time duration. The instrument will display an asterisk
(*) only when these criteria are met.
8.20*mg
/L
24.38°C 11:33AM
STORE REVIEW SEND CALIBRATE
From the Setup menu, press the [STABLE] soft-key to display the following menu.
Stable
PARAMETERS
[
10
]
Time Duration
(
3-19
)
Seconds
[
0.3
]
DO % variation
(
0.0-1.9
)
UP DOWN DIGIT NEXT
This menu is used to change the autostable criteria. Press the [NEXT] soft-key to select between
the time duration and the percent variation. Use the [DIGIT] soft-key to select the digit you wish
to change by pressing [UP] or [DOWN]. When you have finished setting the parameters, press
[ENTER] to confirm. The STABLE sub-menu can be left without making any changes by
pressing the [MODE] key instead of [ENTER]. Operation returns to the setup menu.
If you wish to disable the autostable feature, set the DO% variation to 0.0.
To return to Main mode, press [MODE] two more times.
Main
Stable reading indication

YSI Incorporated Model 5000/5100 Service Manual 8
4.4 SYSTEM SETUP
From the Setup menu, press the [SYSTEM] soft-key to display the following menu.
8.38*mg
/L
24.38°C 11:47AM
AUDIO off TIME / DATE VERSION RS232
The [AUDIO on/off] soft-key allows setting the beeper on or off. The key toggles between an
[AUDIO off] soft-key and an [AUDIO on] soft-key. The present state of the beeper would be the
OPPOSITE of the function shown on the soft-key. If the beeper is currently on, the soft-key
shows “AUDIO off”; i.e., your alternate choice.
The [TIME/DATE] soft-key brings up the following menu to allow setting of the date and time.
Time/Date
09:58:04
01/20/96
UP DOWN DIGIT NEXT
Use the UP, DOWN, DIGIT and NEXT soft-keys to enter the time in 24-hour format. The
display digit that is flashing is increased or decreased by pressing the [UP] or [DOWN] soft-key.
If the [UP] or [DOWN] soft-key is held down, the digit will continue to change until the key is
released. After you have set the hour, press the [NEXT] soft-key to move to the next parameter,
minutes. Repeat the process for the remaining parameters.
When you have finished entering the time and date, press [ENTER] to confirm and return to the
system setup menu. The message “TIME SETTING SAVED” will be displayed on the message line
at the bottom of the screen. The Time/Date sub-menu can be left without making any changes by
pressing the [MODE] key instead of [ENTER].
8.38*mg
/L
24.38°C 9:59AM
TIME SETTING SAVED
AUDIO off TIME / DATE VERSION RS232
The [VERSION] soft-key displays the software version of the instrument on the message line of
the display just above the soft-key descriptions.
The [RS232] soft-key displays the RS232 setup.
System
System
Flashing Digit
Messa
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YSI Incorporated Model 5000/5100 Service Manual 9
[ 2 ] BAUD RATE 19200 RS232
0. 4. 4800
1. 5. 2400
2. 19200 6. 1200
3. 9600
UP DOWN
Select the baud rate by pressing the [UP] or [DOWN] soft-keys.
The remaining RS232 parameters are fixed as follows:
Data Length: 8 bits
Parity: None
Stop Bits: 1
Press [ENTER] to confirm. The RS232 sub-menu can be left without making any changes by
pressing the [MODE] key instead of [ENTER]. Operation returns to the system setup menu.
Press [MODE] to return to the previous menu, Setup. To return to Main mode, press [MODE]
two more times.

YSI Incorporated Model 5000/5100 Service Manual 10
SECTION 5 CALIBRATION
The instructions below explain how to calibrate the system before dissolved oxygen
measurements are taken or testing is performed using the 16423 Test Box.
From the Main mode, press the [CALIBRATE] soft-key to enter Calibration mode. The bottom
row of the display shows the soft-key menu.
98.0*% 8.15
mg/L Calibrate
0.0 ppt 740
mmHg
24.38°C 11:33AM
AUTO CAL DO CAL SETUP DIAGNOSTICS
5.1 DISSOLVED OXYGEN CALIBRATION
Dissolved oxygen calibration can be done automatically with the push of one button (see AUTO
CAL) or manually by entering the desired value in milligrams per liter or percent saturation (see
DO CAL).
BEFORE YOU CALIBRATE you must Setup the meter, as discussed in the Setup section of
this manual, and Prepare the DO probe. Before performing an AUTO CAL, you must check the
barometric pressure reading and calibrate the barometer, if necessary, as shown under
Calibration, Barometer. The Model 5000 does not contain a barometer, therefore, the current
barometric pressure must be entered before an AUTO Cal is performed.
Dissolved oxygen calibration must be done in an environment with a known oxygen content. The
simplest method will be discussed here: calibration in air (water saturated). Calibration in air is
the simplest and most accurate method of calibration.
For air calibration, place the probe in air at 100% relative humidity. To achieve this, the probe
can be placed in a BOD bottle containing 1″of water. No stirring is required in air.
AUTO CAL
1. Prepare the probe according to the instructions in the Probe Operations Manual.
2. Connect the probe to the meter.
3. Place the probe in a BOD bottle containing about 1″of water to provide a 100% relative
humidity environment.
4. Press [ ] to turn the instrument on.
5. Allow the probe to polarize and the temperature to stabilize for at least 15 minutes. If
calibration is performed prematurely the values will drift and may be out of specification.
6. Press the [CALIBRATE] soft-key to change to Calibration mode. The following display will
appear.

YSI Incorporated Model 5000/5100 Service Manual 11
98.0*% 8.15
mg/L Calibrate
0.0 ppt 740
mmHg
24.38°C 11:33AM
AUTO CAL DO CAL SETUP DIAGNOSTICS
7. Model 5100: Verify that the barometer reading is correct. Calibrate the barometer, if
necessary, as shown under Calibration, Barometer.
Model 5000: Enter the current barometric pressure as shown under Calibration, Barometer.
8. Verify that the salinity is set to the correct value (0.0 ppt for air calibration). See Calibration,
Salinity.
Make sure that the display readings are stable, then press the [AUTO CAL] soft-key to calibrate
Dissolved Oxygen. The message “D.O. CALIBRATION SAVED” will be displayed for a few
seconds.
98.0*% 8.15
mg/L Calibrate
0.0 ppt 740
mmHg
24.38°C 11:33AM
D. O. CALIBRATION SAVED
AUTO CAL DO CAL SETUP DIAGNOSTICS
Press [MODE] to return to the Main mode. The instrument is now calibrated and ready to
measure dissolved oxygen and temperature. See Operation, Main Mode, Making Measurements.
DO CAL (MANUAL)
1. Prepare the probe according to the probe instructions.
2. Connect the probe to the meter.
3. Place the probe in a known oxygen environment, such as a BOD bottle containing about 1″
of water to provide a 100% relative humidity environment or a Winkler-titrated sample.
4. Press [ ] to turn the instrument on.
5. Allow the probe to polarize and the temperature to stabilize for at least 15 minutes. If
calibration is performed prematurely the values will drift and may be out of specification.
6. Press the [CALIBRATE] soft-key to change to Calibration mode. The following screen will
be displayed.
Messa
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YSI Incorporated Model 5000/5100 Service Manual 12
8.15
mg/L Calibrate
0.0 ppt 740
mmHg
24.38°C 11:33AM
AUTO CAL DO CAL SETUP DIAGNOSTICS
7. Press the [DO CAL] soft-key to enter the manual DO calibration menu.
98.0% 8.15
mg/L Cal %
0.0 ppt 740
mmHg
24.38°C 11:33AM
UP DOWN DIGIT NEXT
8. Verify that the salinity is set to the salinity value of the calibration environment (0.0 ppt for
air calibration). ). See Calibration, Salinity.
Make sure that the display readings are stable, then enter the calibration value in percent
saturation, using the [UP], [DOWN] and [DIGIT] soft-keys.
If you wish to calibrate in milligrams per liter (instead of percent), use the [NEXT] soft-key to
select mg/L, then enter the calibration value in milligrams per liter as shown below.
98.0*% 08.15
mg/L Cal mg/L
0.0 ppt 740
mmHg
24.38°C 11:33AM
UP DOWN DIGIT NEXT
9. Press [ENTER] to confirm your calibration. The screen will momentarily display “D.O.
CALIBRATION SAVED” as shown below.
98.0*% 8.15
mg/L Calibration
0.0 ppt 740
mmHg
24.38°C 11:33AM
D. O. CALIBRATION SAVED
UP DOWN DIGIT NEXT
Press [MODE] to return to the Main mode. The instrument is now calibrated and ready to
measure dissolved oxygen and temperature.
Flashing digit
Flashin
g
di
g
it
Messa
g
e

YSI Incorporated Model 5000/5100 Service Manual 13
5.2 BAROMETER
The YSI Model 5100 has an internal barometer for pressure compensation during AUTO
Dissolved Oxygen Calibration. This barometer only needs to be calibrated when it is no longer
reading the correct barometric pressure. If the 5100 is kept at a constant ambient temperature
(±10°C), the barometer calibration should be accurate for about 30 days.
The Model 5000 does not contain a barometer, therefore, the current barometric pressure must be
entered before an AUTO Cal is performed. The reading currently displayed is the value that was
entered and stored during the previous calibration.
From the calibration menu press the [DO CAL] soft-key, then press the [NEXT] soft-key until
the barometric pressure is flashing and “Barometer” appears in the top right corner of the display
as follows:
98.0*% 8.15
mg/L Barometer
0.0 ppt 740
mmHg
24.38°C 11:33AM
Press ENTER to SAVE SETTING
UP DOWN DIGIT NEXT
Using the [UP], [DOWN] and [DIGIT] soft-keys, enter the true local barometric pressure. This
corresponds to a reading from a mercury barometer. Do NOT use the pressure reported by the
weather bureau which has been corrected to sea level.
Press [ENTER] to confirm. The message “PRESSURE CALIBRATION SAVED” will be displayed.
5.3 SALINITY
Salt reduces the ability of water to hold oxygen in solution. Enter the salinity of the sample you are
measuring and the meter will automatically compensate for the effect of salinity on dissolved
oxygen. The default setting for salinity is 0.0 ppt. You can enter any value between 0.0 and 40.0 ppt.
From the Calibration menu press the [DO CAL] soft-key, then press the [NEXT] soft-key until
the salinity value is flashing. The top right corner of the screen will display “Salinity” as shown
in the following screen. Remember, if you are manually calibrating in mg/L in water saturated
air, salinity is 0.0 ppt.
98.0* % 8.15
mg/L Salinity
0.0 ppt 740
mmHg
24.55°C 11:35AM
Press ENTER to SAVE SETTING
UP DOWN DIGIT NEXT
Using the [UP], [DOWN] and [DIGIT] soft-keys, enter the salinity value.
Press [ENTER] to confirm. The message “SALINITY SETTING SAVED” will be displayed.
Flashing digit
Flashing digit

YSI Incorporated Model 5000/5100 Service Manual 14
5.4 ZERO CALIBRATION
All oxygen probes have a small background current, even in the absence of oxygen. The Model
5000/5100’s default zero value is based on the average probe’s background current. This default
value may cause errors when measuring low concentrations of oxygen.
For highest accuracy measurements, a zero calibration should be performed to compensate for
the specific background current of the probe in use.
To calibrate to a true zero, place the probe in a zero oxygen environment and adjust the
calibration value to zero.
A standard method for creating such an environment is to dissolve in water excess sodium sulfite
(Na2SO3), and a trace of cobalt chloride (CoCl2). These chemicals will remove all oxygen from
the sample (See Standard Methods for the Examination of Water & Wastewater, method 4500-O
G, 19th edition). Alternatively, you may place the probe in 100% nitrogen gas.
1. Place the probe in the zero oxygen sample and allow at least 20 minutes for the probe to
come to equilibrium.
2. Press the [CALIBRATE] soft-key to change to Calibration mode. The following screen will
be displayed.
98.0*% 8.15
mg/L Calibration
0.0 ppt 740
mmHg
24.38°C 11:33AM
AUTO CAL DO CAL SETUP DIAGNOSTICS
3. Press the [DO CAL] soft-key to enter the manual DO calibration menu.
000.0*% 0.00
mg/L Cal %
0.0 ppt 740
mmHg
24.38°C 11:33AM
UP DOWN DIGIT NEXT
4. Make sure that the display readings are stable, then use the [UP], [DOWN] and [DIGIT] soft-
keys to enter the calibration value of 0.0% (or 0.00 mg/L).
NOTE: The instrument will not except any value other than zero for the first point of a two-point
calibration.
5. Press [ENTER] to confirm your calibration. The screen will momentarily display “D.O.
Calibration saved”.
6. You must now recalibrate in an oxygen environment (see Auto Cal or DO Cal).
NOTE: When you change the zero calibration point, you offset the other value, so that after
zeroing the probe for zero oxygen, you must recalibrate in an oxygen environment.

YSI Incorporated Model 5000/5100 Service Manual 15
SECTION 6 DIAGNOSTICS
5000 and 5100s have a diagnostic mode that can be used for troubleshooting. In Diagnosis mode
you can view specific sensor information, such as DO probe current, DO background current and
pressure sensor offset. This data is useful when trying to isolate problems or prevent error
messages from occurring.
From the Main mode, press the [CALIBRATE] soft-key to enter Calibration mode, then press the
[Diagnosis] soft-key to enter Diagnosis mode. The following screen will be displayed.
Diagnosis
HISTORY SENSOR HELP RESET Ps
6.1 HISTORY
Press the [HISTORY] soft-key to display the following information.
Date Time DO uA %/uA C Diagnosis
02/01 14:12 16.8 5.98 21.9
02/02 08:42 16.3 7.90 28.0
02/05 09:55 17.0 6.42 23.0
02/06 10:58 17.1 7.47 27.9
02/07 13:08 16.9 6.43 22.8
HISTORY SENSOR HELP RESET Ps
The History screen displays information about the last five DO calibrations. This information is
useful for tracking the performance of the DO probe/membrane. The following parameters are
displayed:
Date: The date the calibration was performed.
Time: The time the calibration was performed.
DO uA: The dissolved oxygen calibration current in microamps. The calibration
current (100% saturation at sea level) of an ideal probe using a 1 mil
(standard) membrane is 13.7uA @ 20°C. If the probe current (100%
saturation @ 20°C, 1 mil membrane) is greater than 17.0uA or lower
than 8.0uA, the membrane/probe may need service. See
Troubleshooting, Error Codes, E3 and E4.
%/uA: The slope of the dissolved oxygen probe in percent per microamp
corrected to 20°C. The slope of an ideal probe using a 1 mil membrane is
7.3 %/uA @ 20°C. If the probe slope (1 mil membrane) is greater than
12.6 %/uA or lower than 5.9 %/uA, the membrane/probe may need
service. See Troubleshooting, Error Codes, E3 and E4.
C: The temperature at the time of calibration in °C.

YSI Incorporated Model 5000/5100 Service Manual 16
6.2 SENSOR
Press the [SENSOR] soft-key to display the following sensor diagnostics screen:
System Parameters Sensor
Cal. Temperature = 22.85 C
Probe Slope = 6.43 %/uA @20C
Probe Offset = 0.075 uA
Probe Current = 16.91 uA
Pressure Offset = 830 mbar
Cal. Temperature: The temperature at the time of the last calibration in °C.
Probe Slope: The slope of the dissolved oxygen probe in percent per
microamp corrected to 20°C. The slope of an ideal probe using a
1 mil membrane is 7.3%/uA @ 20°C. If the probe slope (1 mil
membrane) is greater than 12.6 %/uA or lower than 5.9 %/uA,
the membrane/probe may need service. See Troubleshooting,
Error Codes, E3 and E4.
Probe Offset: The zero offset current (background current) of the DO probe in
microamps. The factory default value is 0.075 uA. This value
will only change when a zero calibration is performed (see
Calibration, Zero Calibration). If this value is greater than
0.15uA (after a zero calibration) the membrane/probe may need
service. See Troubleshooting, Error Code E2.
Probe Current: The present (real time) DO probe current in microamps.
Pressure Offset: The offset of the barometer in millibars.
Press [MODE] to return to the Diagnosis menu. Press [MODE] two more times to return to the
Main menu.
6.3 RESET PS
The [RESET Ps] soft-key (Reset Parameters) is used to reset all instrument parameters to the
factory default values. This is useful when the parameters have been changed or corrupted, such
as when new software is loaded. Press the [RESET Ps] soft-key to display the following:
Reset
Press ENTER to RESET Parameters
HISTORY SENSOR HELP RESET Ps
Press [ENTER] to confirm. If you do NOT wish to reset the parameters, press [MODE] to return
to the Diagnosis menu.