TPS miniCHEM-DO2 User manual

Congratulations !
Your new miniCHEM-DO2monitor is the latest in simple, reliable process
monitoring instrumentation. With correct operation and maintenance, your
miniCHEM-DO2will give you many years of reliable service.
The miniCHEM-DO2is a breeze to operate. This manual has been designed to
help you get started, and also contains some handy application tips. If at any
stage you require assistance, please contact either your local TPS representative
or the TPS factory in Brisbane.
The manual is divided into the following sections:
1. Table of Contents
Each major section of the handbook is clearly listed. Sub-sections have also
been included to enable you to find the information you need at a glance.
2. Introduction
The introduction has a diagram and explanation of the display and controls of
the miniCHEM-DO2. It also contains a full listing of all of the items that you
should have received with the unit. Please take the time to read this section, as
it explains some of items that are mentioned in subsequent sections.
3. Main Section
The main section of the handbook provides complete details of the
miniCHEM-DO2, including operating modes, calibration, troubleshooting,
specifications, and warranty terms.
4. Appendices
Appendices containing background information and application notes are
provided at the back of this manual.
miniCHEM-DO2
Process Monitor
Version : 2.11
Date : 22/11/2002
Author : MS

Page 2
TPS Pty Ltd
ABN 30 009 773 371
4 Jamberoo Street
Springwood, Brisbane,
Australia, 4127
Phone : [phone]
International : 61 7 32 900 400
Fax : [phone]
International : 61 7 3808 4871
Email : [email protected]
Web : www.tps.com.au

Page 3
Contents
1. Introduction .............................................................................................4
1.1 miniCHEM-DO2Illustration ........................................................................4
1.2 Unpacking Information ................................................................................6
1.3 Specifications...............................................................................................7
2. Operating Modes .....................................................................................8
3. Installation and Set-up............................................................................9
3.1 Connection and Configuration Diagram.......................................................9
3.2 Mounting the Enclosure.............................................................................10
3.3 Mounting the Sensors.................................................................................10
3.4 Terminal Connections................................................................................11
3.5 Setting the Control Limit ...........................................................................11
3.6 Selecting Current or Voltage Output ..........................................................14
3.7 Calibrating the 4 to 20mA Output..............................................................15
4. Calibration..............................................................................................16
4.1 Calibration Procedure.................................................................................16
4.2 Calibration Notes .......................................................................................17
5. Process Monitoring...............................................................................18
6. Automatic Dosing..................................................................................18
7. Manual Dosing.......................................................................................18
8. Fuse Replacement.................................................................................18
9. Troubleshooting....................................................................................19
9.1 Instrument Function Troubleshooting.........................................................19
9.2 Dissolved Oxygen Troubleshooting............................................................20
10. Appendices ........................................................................................21
10.1 ppM (mg/L) Calibration Table ...................................................................21
10.2 Selecting % Saturation or ppM (mg/L) Readout .........................................22
10.3 Selecting YSI or ED1M Dissolved Oxygen Sensor .....................................24
10.4 Cleaning the Dissolved Oxygen Sensor ......................................................26
10.5 Maintenance of the Membrane...................................................................27
10.6 Dissolved Oxygen Sensor Storage ..............................................................27
10.7 Terminal connections when 12V DC option is fitted...................................28
10.8 Relay Output Wiring Examples for mains powered units............................29
10.9 Relay Output Wiring Examples for 12V DC powered units ........................30
11. Warranty.............................................................................................31
12. Drilling Template................................................................................33

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1. Introduction
1.1 miniCHEM-DO2Illustration

Page 5
¬Alarm LED
The Alarm LED provides visual indication of when the control limit has been
exceeded. The control limit can be set for a “too high” or a “too low” alarm.
See section 0.
-Limit Control
Adjust this control to the Dissolved Oxygen value at which the Alarm LED
and (optional) relay output are activated. See section 0.
®Zero Calibrate Control
Adjust this control to calibrate the miniCHEM-DO2in an Oxygen-free
solution. See section 4.1.
¯Span Calibrate Control
Adjust this control to calibrate the miniCHEM-DO2in air, or against a
Winkler titration. See section 4.1.
°Function Switch
The Function Switch is used to select the mode of operation. See section 2.
±Display Window
The miniCHEM-DO2has a large, easy to read LCD display. The units of
measurement are clearly shown in the window beneath the display.
ÆTerminal Cover
The terminal cover provides easy access to all of the connections, (optional)
relay output fuse, configuration jumpers and user-adjustable trimmers. The
cover is water resistant to IP65.

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1.2 Unpacking Information
Before using your new miniCHEM-DO2, please check that the following
accessories have been included: Part No
1. miniCHEM-DO2Process Monitor.........................113140
2. miniCHEM-DO2Handbook ..................................130050
Options that may have been ordered with your miniCHEM-DO2:
TPS Dissolved Oxygen Sensor (submersible to 3 metres max)…
1. ED1M Dissolved Oxygen sensor (no cable)............123440
2. 5m cable for ED1M...............................................123236
3. Extended cable (per metre)..................................... 130040
YSI Dissolved Oxygen Sensor and separate cable…
1. EDYSI Dissolved Oxygen sensor (no cable) ...........123204
2. 5m cable for EDYSI ..............................................123210
3. Extended cable (per metre)..................................... 130040
Instrument options…
1. Relay control output...............................................130342
2. 4-20mA loop-powered, remote LCD....................... 130080
Spares…
1. Membrane Kit for ED1M.......................................123301
2. Membrane Kit for EDYSI...................................... 123300
3. Sodium Sulphite for Zero calibration...................... 123302

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1.3 Specifications
Ranges...........................................................................0 to 199.9 % Saturation
...................................................................................or 0 to 19.99 ppM (mg/L)
........................................................................................................(Factory-set)
Resolution ................................................................................0.1 % Saturation
.............................................................................................or 0.01 ppM (mg/L)
Accuracy...............................................................................±0.2 % of full scale
Linearity...................................................................................................±0.1 %
Repeatability.............................................................................................±0.2 %
Ambient Drift .........................................................<0.05 % span per 1oC change
Long term drift ............................................................................<0.2% per year
Zero Range................................................................................................±10 %
Span Range ......................................................................................70 to 130 %
Temperature Compensation................ Dual automatic temperature compensation
.......................................................................... system, 0 to 50 OC (sensor limit)
Enclosure........................................................ Polycarbonate, waterproof to IP65
Display...........................................12.7 mm LCD (optional remote 4-20mA loop
powered display available)
Analogue Outputs........................... 4 to 20mA (500 Ohms max. loop resistance )
0 to 1 V DC (min. load 1000 Ω)
0 to 10 V DC optional (min. load 1000 Ω)
Control Output (optional).................................... Clean contact changeover relay,
rated to 2A at 240V AC
Isolation............................................................Galvanic isolation of sensor input
Power.................................................... 240V AC, 50/60Hz (120V AC optional)
Dimensions............................................................................172 x 160 x 71 mm
Mass ...................................................................Instrument only :Approx 800g
Full Kit :Approx 1.5kg
Operating Environment:.......................................Temperature :0 to 45 oC
Humidity :0 to 95 % R.H.

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2. Operating Modes
The function switch is used to select the required mode. The four operating modes
available are…
1. SET LIMIT :Switch to SET LIMIT when setting the Dissolved Oxygen
value at which the Alarm LED and (optional) relay output are
activated. The relay output is not operational in this mode.
See section 0.
2. STANDBY :Switch to STANDBY to inhibit the Alarm LED and
(optional) output relay action. Select this mode for
calibration, or when automatic dosing is not required.
3. AUTO :Switch to AUTO to enable the Alarm LED and (optional)
relay output. These will be activated when the Dissolved
Oxygen is outside the limit value. See section 0.
4. MANUAL :Switch to MANUAL to manually switch on a control device
or alarm when the optional relay output is fitted. The relay
output will be activated for as long as the miniCHEM-DO2is
in this mode, regardless of the Dissolved Oxygen reading.
See section 7.

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3. Installation and Set-up
3.1 Connection and Configuration Diagram
The diagram below is provided as a reference for the terminal connections,
configuration jumpers and user-adjustable trimmers that are discussed throughout
this section.

Page 10
3.2 Mounting the Enclosure
The miniCHEM-DO2can be wall-mounted with 3 screws. Two mounting points
are located underneath the terminal cover, and are positioned so that they do not
affect the waterproofing of the enclosure. The third mounting point is centrally
located near the top of the rear of the enclosure, and has been designed to hook
over a screw-head. The dimensions for the mounting screw centres are provided on
the rear of the enclosure. The last page of this manual may be photocopied or
removed for use as a drilling template.
3.3 Mounting the Sensors
Mounting the sensor is a very important aspect of the installation, and is often done
incorrectly. In automatic control situations, the sensor should always be mounted
as close as possible to the injection point. This will cause the sensor to detect the
added oxygen or chemicals immediately, and shut the addition off until mixing has
taken place. For in-line mounting, it is important that oxygen or chemicals are
injected upstream. Additionally, the line must be run through a mixing chamber,
such as a large drum, to ensure that the injected oxygen or chemical has mixed in
properly by the time the solution flows past the sensor. There must always be
adequate flow of fresh sample past the sensor, for accurate monitoring. The
diagrams below show typical mounting arrangements for “dip” mounting and in-
line mounting.
Dip Mounting
1. Injection point close to sensor.
2. Continuous stirring.
In-line Mounting
1. Injection point upstream from and
close to sensor.
2. Mixing container after injection and
before sensor.
3. DO2sensor mounted as close to
vertical as practical, through a
suitable gland fitting.

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3.4 Terminal Connections
Note: The power connections detailed below are for normal mains power. Refer
to section 10.7 for power wiring details when the 12V DC power option is fitted.
Terminal No. Connection Colour
1ATC Sensor for ppM operation Red
2ATC Sensor for ppM operation Blue
3No Connection
4Common Black
5DO2Sensor Anode Green
6DO2Sensor Cathode Yellow
7+ve of current or voltage output Customer-defined
8-ve of current or voltage output Customer-defined
9No Connection
10 Normally Closed contact of
(optional) relay output Customer-defined
11 Common contact of (optional) relay
output Customer-defined
12 Normally Open contact of
(optional) relay output Customer-defined
13 240V AC Active input Brown (standard colour)
14 Duplicate 240V AC Active contact.
See section 10.7.Brown (standard colour)
15 240V AC Earth input Green (standard colour)
16 Duplicate 240V AC Earth contact.
See section 10.7.Green (standard colour)
17 240V AC Neutral input Blue (standard colour)
18 Duplicate 240V AC Neutral
contact. See section 10.7.Blue (standard colour)
∗∗ The ATC connection to terminals 1 & 2 is only for when the unit is reading
ppM (mg/L) units. DO NOT connect these for % Saturation readout.

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3.5 Setting the Control Limit
The control limit can be set over the full scale of the miniCHEM-DO2, as a “too
high” or a “too low” trip point. The hysteresis around this set point can be also be
adjusted, if necessary. See section 3.5.3 for an explanation of hysteresis.
3.5.1 Setting the limit value
1. Switch the miniCHEM-DO2to SET LIMIT.
The control limit value is now displayed. Note that the Alarm LED and
(optional) output relay are now disabled. The 4-20mA or 0-1V outputs are still
active, and proportional to displayed value.
2. Adjust the LIMIT control until the display reads the desired trip point value.
3.5.2 Setting the alarm/control direction
The control limit can be set as a “too high” or “too low” trip point using the Lo/Hi
Control jumpers in the terminal area. The miniCHEM-DO2must be switched
OFF before changing jumper settings.
The jumper settings for a “too low” trip point are…
Low High
The jumper settings for a “too high” trip point are…
Low High

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3.5.3 Adjusting the Hysteresis
The hysteresis is the Dissolved Oxygen range over which the alarm/control output
remains switched on, once the trip point has been exceeded.
For example, if the limit is set to 10.00 ppM, as a“too low” trip point, with a
hysteresis of ±0.10 ppM, the alarm/control output is switched ON when the
reading goes to 9.90 ppM(i.e. 10.00 -0.10). The output is not switched OFF until
the reading goes back up to 10.10 ppM (i.e. 10.00 + 0.10).
The hysteresis stops the relay “chattering” around the set point, by providing a
buffer between the points at which the output is switched ON and OFF. This
feature can significantly increase the life of aerators, pumps, solenoid valves etc.
The factory-set hysteresis is approximately ±0.10 ppM, as in the example above.
The hysteresis can be increased to as high as ±2.00 ppM with the HYSTERESIS
trimmer in the terminal area. For units set up for % Saturation, the factory-set
hysteresis is approximately ±1.0 % Saturation, which can be adjusted to ±20.0 %
Saturation.
Turning the HYSTERESIS clockwise increases the hysteresis and turning it anti-
clockwise decreases the hysteresis.
TPS DOES NOT recommend that this setting be altered, unless it is absolutely
necessary.
The HYSTERESIS trimmer should only be adjusted a little at a time. The process
being controlled should then be closely monitored over a time to ensure that the
desired control is being achieved.

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3.6 Selecting Current or Voltage Output
The Current/Voltage Output jumpers in terminal section can be user-set for
either 4 to 20mA or 0 to 1V DC output. The miniCHEM-DO2must be switched
OFF before changing jumper settings.
The jumper settings for 4 to 20 mA output are:
CVCVC
The jumper settings for 0 to 1V DC output are:
CVCVC
Note that the spare jumper has been fitted to a spare Current/Voltage Output
jumper pin. This is a safe place to keep it, in case the miniCHEM-DO2needs to be
reset to current output in the future.
0 to 10V DC output is available as a factory fitted option. The jumper settings
are the same as detailed above, but the 0 to 1V DC output will no longer be
available.

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3.7 Calibrating the 4 to 20mA Output
The 4 to 20mA output of the miniCHEM-DO2is factory calibrated. However,
TPS has provided calibration controls for the 4mA and 20mA points in case this
requires adjustment in the field. Only a limited amount of adjustment is available,
as the miniCHEM-DO2is designed for 4 to 20mA output for the full scale of the
instrument.
Calibrating the 4 to 20mA output…
1. Connect a Digital Milliamp Meter between terminals 7 and 8.
2. Switch the miniCHEM-DO2to SET LIMIT.
3. Adjust the LIMIT control until the display reads 0.00.
4. Adjust the ZERO/4mA trimmer in the terminal area until the Digital Milliamp
Meter reads 4 mA.
5. Adjust the LIMIT control until the display reads 19.99 ppM or 199.9 %
Saturation.
6. Adjust the SPAN/20mA trimmer in the terminal area until the Digital
Milliamp Meter reads 20 mA.
In the event that the LIMIT control does not have sufficient adjustment to
reach 0.00 or 19.99/199.9, calculate the expected output level and use this
for calibration. Remember that the difference between 0 and 19.99/199.9 is
to be made 16mA.

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4. Calibration
4.1 Calibration Procedure
1. Switch the miniCHEM-DO2on.
2. Ensure that the Dissolved Oxygen sensor is correctly connected (see section
3.4).
3. Set the function switch to STANDBY, to ensure that the (optional) relay
output is not activated by the Dissolved Oxygen sensor’s response.
4. Rinse the Dissolved Oxygen sensor in distilled water and blot dry.
Zero Calibration
5. (a) Place the sensor into an oxygen-free solution. This solution may be
prepared by dissolving 2g of Sodium Sulphite in 100mL of distilled water.
A 50g bottle of Sodium Sulphite powder is supplied with new ED1M
and EDYSI sensors for this purpose (part number 123302).
(b)Allow the reading to stabilise at or near zero. This may take 2-3 minutes.
(c) Adjust the ZERO control until the display reads 0.00 ppM or 0.0 %
Saturation.
6. Rinse the Dissolved Oxygen sensor in distilled water and blot dry.
Span Calibration
7. (a)Hang the Dissolved Oxygen sensor in air. The tip of the sensor should be
pointing downwards.
(b)Allow the reading to stabilise. After a zero calibration, this may take up to
5 minutes.
8. (c) For % Saturation readout, adjust the SPAN control until the display reads
100.0.
For ppM readout, adjust the SPAN control for the ppM (mg/L) Dissolved
Oxygen value at the current air temperature, and the expected salinity value of
the sample solution. A table is provided in section 10.1 for this purpose.
If the expected salinity value of the sample solution is quite high, there may not
be enough adjustment in the SPAN control to calibrate the readout. If this is the
case, please see section 10.3 for details on how to set the internal jumpers to
allow for higher salinities.
9. The miniCHEM-DO2is now calibrated and ready for Dissolved Oxygen
measurements.

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4.2 Calibration Notes
1. A Span calibration should be performed at least weekly. In applications where
the sensor can become dirty or coated, such as sewage effluent, mining slurries
etc, a Span calibration may have to be done daily.
2. The Zero calibration is quite stable long term. Monthly Zero calibration is
recommended, mainly as a routine check.
3. Both a Zero and a Span calibration need to be performed when the membrane is
replaced.

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5. Process Monitoring
Once the miniCHEM-DO2has been installed, connected and calibrated, it can be
used for continuous monitoring. To monitor the process, WITHOUT any control or
alarm functions switch the function switch to STANDBY.
6. Automatic Dosing
For Automatic Alarming or Control, switch the function switch to AUTO to enable
the Alarm LED and the (optional) relay output. These will be switched ON while
the Dissolved Oxygen exceeds the limit value, and will switch OFF once the
Dissolved Oxygen is back within the limit.
7. Manual Dosing
From time to time, the control device (aerator etc.) may be required, even when the
Dissolved Oxygen is within the limit value. To do this, simply switch the function
switch to MANUAL, if the (optional) relay output is fitted.
NOTE: The output will be ON continuously while the function switch is set to
MANUAL. It will not be switched OFF again until the switch is set
back to one of the other modes.
8. Fuse Replacement
If the current drain from any device connected to the output relay exceeds 1 Amp,
the output protection fuse will blow.
To replace the fuse…
1. SWITCH THE miniCHEM-DO2OFF.
2. Pull out the black fuse carrier.
3. Replace the blown fuse
4. Push the fuse carrier with the new fuse back into place.
ALWAYS REPLACE THE FUSE WITH A 1 AMP, 240V
FUSE. USING A FUSE WITH HIGHER CURRENT RATING
MAY DAMAGE YOUR CONTROLLER, VOIDING THE
WARRANTY.
Before switching the miniCHEM-DO2back to AUTO mode, ensure that the cause
of the blown fuse has been eliminated.
If the current drain of the device connected to the relay output is greater than 1
Amp, an external contactor should be used. Please consult an electrical contractor
or TPS for details.

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9. Troubleshooting
9.1 Instrument Function Troubleshooting
Symptom Possible Causes Remedy
No display 1. Mains power input not
switched on.
2. Mains power input
incorrectly connected.
3. Instrument is faulty.
Switch power ON.
Check connections (see section
3.4).
Return to TPS for repair.
Alarm LED or
(optional) relay
output do not
operate when limit
is exceeded.
1. Limit not set correctly for
“too high” or “too low”
alarm/control.
2. Optional relay output not
fitted.
3. Hysteresis too large.
4. Fuse has blown.
5. Instrument is faulty.
Set the Lo/Hi Output jumpers
correctly (see section 3.5.2).
Return unit to factory to have
relay output fitted (part no
130342).
Check and adjust the
HYSTERESIS trimmer (see
section 3.5.3). If in doubt, set
this to minimum level.
Check and replace fuse if
necessary (see section 8).
Return to TPS for repair.
Incorrect analogue
output signal. 1. Current/Voltage Output
jumpers incorrectly set for
required output.
2. 4-20mA loop resistance too
high.
3. Load on 0-1V DC output is
too low.
4. 4-20mA output is not
calibrated.
5. Instrument is faulty.
Check that the Current/Voltage
Output jumpers are correctly
set for 4-20mA or 0-1V, as per
requirements. Adjust if
necessary (see section 3.6).
Ensure loop resistance does not
exceed 500 Ohms.
Ensure load is 1000 Ohms
minimum.
Calibrate 4-20mA output (see
section 3.7).
Return to TPS for repair.

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9.2 Dissolved Oxygen Troubleshooting
Symptom Possible Causes Remedy
•Zero calibration
fails (Zero is
greater than 10%)
•Air calibration
fails (Span is less
than 70% or
greater than
130%).
•Unstable or
inaccurate
readings.
1. Membrane is leaking or
broken.
2. Gap between membrane
and gold cathode is dry.
3. Incorrectly fitted
membrane.
4. Sensor is empty.
5. Sensor is faulty.
Replace membrane and refill
sensor.
ED1M: Undo the barrel 3
turns, then re-tighten to re-
flush the filling solution.
EDYSI: Gently pump the
pressure compensation
diaphragm to re-flush the
filling solution.
Membrane should be smooth
and convex with no wrinkles.
Re-fit membrane if necessary.
Replace membrane and re-fill
electrode.
Return sensor to factory for
repair or replacement
Blackened Silver
anode wire Electrode has been exposed to sulphides or other chemical
poisoning.
See section 10.4 for the sensor
cleaning procedure. If no
improvement, return to the TPS
factory for cleaning and service.
Tarnished or
scratched Gold
cathode.
Sensor has been chemically
poisoned or physically
damaged.
Return to the TPS factory for
cleaning and service.
Meter reads “1. ”
(over-range
reading).
1. Sensor has not yet
polarised.
2. Electrode is faulty
Wait for 2-3 minutes for the
electrode to polarise after the
miniCHEM-DO2is switched
on.
Return electrode to factory for
repair or replacement.