TPS miniCHEM-Redox User manual

Congratulations !
Your new miniCHEM-Redox monitor is the latest in simple, reliable process
monitoring instrumentation. With correct operation and maintenance, your
miniCHEM-Redox will give you many years of reliable service.
The miniCHEM-Redox is 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-Redox. 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-Redox, 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
-
Redox
Process Monitor
Version : 2.01
Date : 27/09/2006

Page 2
TPS Pty Ltd
ABN 30 009 773 371
Unit 6 / 253 Leitchs Road
Brendale, QLD,
Australia, 4500
Phone : [phone]
International : 61 7 32 058 027
Fax : [phone]
International : 61 7 3808 4871
Email : [email protected].au
Web : www.tps.com.au

Page 3
Contents
1. Introduction .................................................................................................. 4
1.1 miniCHEM-Redox Illustration .............................................................................. 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..................................................................................... 12
3.6 Selecting Current or Voltage Output ................................................................... 14
3.7 Calibrating the 4 to 20mA Output ....................................................................... 15
3.8 CMRR Control .................................................................................................... 16
3.9 Factory Config. Jumpers ..................................................................................... 16
4. Calibration .................................................................................................. 17
4.1 Calibration Procedure.......................................................................................... 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 Redox Troubleshooting ....................................................................................... 20
10. Warranty.................................................................................................. 21
11. Appendices............................................................................................. 23
11.1 Terminal connections when 12V DC option is fitted...................................... 23
11.2 Relay Output Wiring Examples for mains powered units............................... 24
11.3 Relay Output Wiring Examples for 12V DC powered units ........................... 25
11.4 Drilling Template............................................................................................ 26

Page 4
1. Introduction
1.1 miniCHEM-Redox Illustration

Page 5
1 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 3.5.
2 Limit Control
Adjust this control to the Redox value at which the Alarm LED and
(optional) relay output are activated. See section 3.5.
3 Zero Calibrate Control
Adjust this control to calibrate the miniCHEM-Redox in Redox standard,
such as ZoBell. See section 4.1.
4 Span Calibrate Control
This control is not required for the miniCHEM-Redox.
5 Function Switch
The Function Switch is used to select the mode of operation. See section 2.
6 Display Window
The miniCHEM-Redox has a large, easy to read LCD display. The units of
measurement are clearly shown in the window beneath the display.
7 Terminal 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.

Page 6
1.2 Unpacking Information
Before using your new miniCHEM-Redox, please check that the following
accessories have been included:
Part No
1. miniCHEM-Redox Process Monitor...................... 111142
2. ZoBell Redox Standard............................................ 121309
(200mL each of Part A and Part B)
3. miniCHEM-Redox Handbook ............................... 130050
Options that may have been ordered with your miniCHEM-Redox:
Dip mounted Redox sensor, and submersible assembly…
1. Submersible, Non-flow Redox Sensor, 5m .............111260
2. Intermediate Junction Redox Sensor, 5m ................ 121267
3. Submersible protective housing for Redox sensor... 111303
Screw-in Redox sensor, and adaptor for 40mm PVC pipe…
1. Screw-in, Non-flow Redox Sensor, 5m................... 111262
2. ¼” BSP thread adaptor for 40mm PVC pipe ........... 111305
Instrument options…
1. Relay control output ................................................ 130342
2. 4-20mA loop-powered, remote LCD....................... 130080

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1.3 Specifications
Range............................................................................................... 0 to +1000 mV
or 0 to -1000 mV (factory option)
Resolution....................................................................................................... 1 mV
Accuracy....................................................................................................... ±1 mV
Linearity........................................................................................................ ±1 mV
Repeatability................................................................................................. ±1 mV
Ambient Drift ................................................................................ <0.02% span/
o
C
Long term drift.................................................................................<0.1% per year
Zero Range ............................................................................................... ±100 mV
Span Range............................................................................................80 to 110%
Input Impedance ................................................................................... >3 x 10
12
Ω
Common Mode Rejection.............................................................................120 dB
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
o
C
Humidity :0 to 95 % R.H.

Page 8
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 Redox value at which
the Alarm LED and (optional) relay output are activated. The
relay output is not operational in this mode. See section 3.5.
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 Redox is
outside the limit value. See section 3.5.
4. MANUAL : Switch to MANUAL to manually dose chemicals when the
optional relay output is fitted. The relay output will be
activated for as long as the miniCHEM-Redox is in this
mode, regardless of the Redox reading. See section 7.

Page 9
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-Redox can 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 sensors is a very important aspect of the installation, and is often
done incorrectly. In automatic control situations, the sensors should always be
mounted as close as possible to the injection point. This will cause the sensors to
detect the added chemicals immediately, and shut the addition off until mixing
has taken place. For in-line mounting, it is important that chemicals are injected
upstream. Additionally, the line must be run through a mixing chamber, such as a
large drum, to ensure that the injected chemical has mixed in properly by the time
the solution flows past the sensors. 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 In-line Mounting
1. Injection point close to sensor. 1. Injection point upstream from
2. Submersible housing to protect and close to sensor.
sensors and waterproof rear of 2. Mixing container after injection
cable (part no 111303). and before sensor.
3. Continuous stirring. 3. Redox sensor mounted as close to
vertical as practical.

Page 11
3.4 Terminal Connections
Note: The power connections detailed below are for normal mains power. Refer
to section 11.1 for power wiring details when the 12V DC power option is fitted.
Terminal
No.
Connection Colour
1 No Connection
2 No Connection
3 Solution Guard Customer-defined.
Green is recommended.
4 Redox Shield (if fitted) Green
5 Redox Reference Black
6 Redox Signal Clear
7 +ve of current or voltage output Customer-defined
8 -ve of current or voltage output Customer-defined
9 No 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 11.1.
Brown (standard colour)
15 240V AC Earth input Green (standard colour)
16 Duplicate 240V AC Earth contact.
See section 11.1.
Green (standard colour)
17 240V AC Neutral input Blue (standard colour)
18 Duplicate 240V AC Neutral
contact. See section 11.1.
Blue (standard colour)

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3.5 Setting the Control Limit
The control limit can be set over the full scale of the miniCHEM-Redox, 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-Redox to 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-Redox must 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

Page 13
3.5.3 Adjusting the Hysteresis
The hysteresis is the Redox 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 700 mV, as a “too low” trip point, with a
hysteresis of ±10 mV, the alarm/control output is switched ON when the reading
goes to 690 mV (i.e. 700 - 10). The output is not switched OFF until the reading
goes back up to 710 mV (i.e. 700 + 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 pumps and solenoid valves.
The factory-set hysteresis is approximately ±10 mV, as in the example above. The
hysteresis can be increased to as high as ±40 mV with the HYSTERESIS
trimmer in the terminal area. 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.

Page 14
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-Redox must be
switched OFF before changing jumper settings.
The jumper settings for 4 to 20 mA output are:
C V C V C
The jumper settings for 0 to 1V DC output are:
C V C V C
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-Redox needs
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-Redox is 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-Redox is 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-Redox to SET LIMIT.
3. Adjust the LIMIT control until the display reads 0.
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 1000 (or -1000).
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 or 1000 (or -1000), calculate the expected output level and use this
for calibration. Remember that the difference between 0 and 1000 (or -1000)
mV is to be made 16mA.

Page 16
3.8 CMRR Control
The Common Mode Rejection Ratio (CMRR) is factory-set with the CMRR
trimmer.
DO NOT ATTEMPT TO ADJUST THE CMRR TRIMMER.
If this trimmer is accidentally re-set, the unit would best be returned to the factory
for re-calibration.
3.9 Factory Config. Jumpers
The Factory Config. jumpers are factory set, and must not be altered. In case
any of these jumpers are changed or removed, re-fit them as shown below. The
miniCHEM-Redox must be switched OFF before changing jumper settings.
The setting of the Factory Config. jumpers is different for 0 to +1000mV and 0 to
-1000mV. When the miniCHEM-Redox is factory-set for either of these two
ranges, further changes are made inside the unit. DO NOT change these jumpers
to change the display range.
0 to +1000mV OR 0 to -1000mV
Factory Factory
Config. Config.

Page 17
4. Calibration
4.1 Calibration Procedure
1. Switch the miniCHEM-Redox on. Set the function switch to STANDBY, to
ensure that the (optional) relay output is not activated when placing the
Redox sensor into standards.
2. Connect the Redox sensor and ensure that a solution guard rod is fitted. (see
section 3.4). Remove the wetting cap from the Redox sensor.
3. Rinse the Redox sensor and guard rod in distilled water and blot them dry.
4. Make up a 1:1 solution of ZoBell Part A and ZoBell Part B. If a small vessel
is used for calibration, around 10mL of each should suffice.
5. Place Redox sensor and guard rod into the ZoBell standard. Ensure that the
Platinum tip and reference junction are both covered (see diagram below).
6. When the reading has stabilised, adjust the ZERO control until the display
shows the value of the ZoBell standard. This will be one of the following…
a) 229 mV for Ag/AgCl reference systems filled with saturated KCl.
(All of the Redox sensors listed in section 1.2 are this type.)
b) 192 mV for Ag/AgCl reference systems filled with 1 Molar KCl.
c) 192 mV for Calomel reference systems.
7. Rinse the Redox sensor and guard rod in distilled water and blot them dry.
8. Discard the used made-up ZoBell standard.
9. The miniCHEM-Redox is now calibrated and ready for Redox
measurements. Calibration should be performed at least monthly. Of course,
more frequent calibration will result in greater confidence in results.

Page 18
5. Process Monitoring
Once the miniCHEM-Redox has 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 Redox exceeds the limit value, and will switch OFF once the Redox is
back within the limit.
7. Manual Dosing
From time to time, a dose of chemical may be required even when the Redox 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 1Amp,
the output protection fuse will blow.
To replace the fuse…
1. SWITCH THE miniCHEM-Redox OFF.
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-Redox back 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.

Page 19
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.

Page 20
9.2 Redox Troubleshooting
Symptom Possible Causes Remedy
Span calibration
fails (insufficient
range with SPAN
control).
1. ATC probe connected.
2. Platinum tip not clean.
3. Redox electrode is aged.
4. Redox standard is
inaccurate.
Redox does not require an ATC
probe. The Span range will be
reduced if an ATC probe is
fitted. Ensure that there are no
connections to terminals 1 and 2
(see section 3.4).
Clean platinum tip as per
instructions supplied with the
electrode.
Attempt rejuvenation, as per
instructions supplied with the
electrode. If not successful,
replace electrode.
Replace Redox standard.
Unstable readings. 1. Solution guard not fitted.
2. Reference junction blocked.
3. Platinum tip not clean.
4. Reference junction not
immersed.
5. KCl crystals around
reference junction, inside
the electrolyte chamber.
Connect a solution guard rod, to
terminal 3 (see section 3.4).
Clean reference junction, as per
instructions supplied with the
electrode.
Clean platinum tip as per
instructions supplied with the
electrode.
Ensure that the platinum tip
AND the reference junction are
fully immersed (see diagram in
section 4.1)
Rinse electrolyte chamber with
warm distilled water until
dissolved. Replace electrolyte.
Inaccurate readings,
even when
calibration is
successful.
Reference junction blocked. Clean reference junction, as per
instructions supplied with the
electrode.
Displays around 0
mV in all solutions
Electrical short inside electrode
or in cable.
Test system with a new
electrode and replace if
necessary.