EUTECH INSTRUMENTS ALPHA PH 500 PHORP 2-WIRE TRANSMITTER (REVISION... User manual

Instruction Manual
pH 500 LCD Transmitter
pH/ORP Transmitter with Display
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68X216829
Rev 2 05/04

Preface
This manual serves to explain the use of the pH 500 transmitter. It functions in two
ways, firstly as a step by step guide to help you to operate the transmitter.
Secondly, it serves as a handy reference guide. It is written to cover as many
anticipated applications of the transmitter as possible. If there are doubts in the use
of the transmitter, please do not hesitate to contact the nearest Authorized
Distributor.
Eutech Instruments / Oakton Instruments will not accept any responsibility for
damage or malfunction to the transmitter caused by improper use of the instrument.
Remember to fill in the guarantee card and mail it back to your authorized
distributor.
The information presented in this manual is subject to change without notice as
improvements are made, and does not represent a commitment on the part of
Eutech Instruments / Oakton Instruments.
Copyright © 2002
All rights reserved
Eutech Instruments / Oakton Instruments
Rev 2 05/04

TABLE OF CONTENTS
1INTRODUCTION 1
2PREPARATION 2
2.1 Power Supply Requirements (SL2 Position) 3
2.2 Connecting the Electrode and Temperature Probe (SL1 Position) 3
3INSTALLATION 5
3.1 Wall Mount 5
3.2 Panel Mount 6
4DISPLAY AND KEYPAD FUNCTIONS 7
4.1 Display 7
4.2 Keypad 8
5CALIBRATION 9
5.1 Preparing the Transmitter for Calibration 9
5.2 pH Calibration 10
5.3 Relative mV Calibration 11
5.4 Temperature Calibration 11
6ADVANCED SETUP FUNCTIONS 12
6.1 Offset Setting (Unavailable in ORP mode) 12
6.2 Output Range Setting 13
6.3 Temperature Compensation Setting (Unavailable in ORP mode) 14
6.4 HOLD Current Setting 17
6.5 Out-of-Range Current Setting 17
6.6 Configuration 18
7PROBE CARE AND MAINTENANCE 20
8TROUBLE SHOOTING GUIDE 22
9SPECIFICATIONS 23
10 TECHNICAL DIMENSIONS 24
11 ACCESSORIES 25
12 WARRANTY 27
13 RETURN OF ITEMS 27

Instruction Manual pH 500
- 1 -
1 INTRODUCTION
Thank you for selecting a pH 500 pH/ORP Transmitter. This transmitter is a
microprocessor-based instrument that is designed to be sturdy and user-friendly. It
is capable of measuring pH, mV and temperature.
This transmitter has many user-friendly features – all of which are completely
accessible through the water-resistant membrane keypad. Your transmitter includes
an instruction manual and a warranty card.
Please read this manual thoroughly before operating your transmitter.
MEAS
°C
READY
.
.
A
TC
pH

Instruction Manual pH 500
- 2 -
2 PREPARATION
Remove screws from the four corners at the back of the Transmitter, and remove
back cover.
Connectors should be exposed as follows:
Figure 1 – Connection Guide
All wiring is done on 2 detachable connectors: –
1. 9-pin connector (located on SL1 position) for pH electrode, temperature
sensor and potential matching pin (PMP); &
2. 3-pin connector (located on SL2 position) for power supply.
Using a suitable screwdriver, loosen screws from top of connector.
When inserting the wires, always hold connector with top screws facing up.

Instruction Manual pH 500
- 3 -
2.1 Power Supply Requirements (SL2 Position)
This transmitter requires a 12 to 24V DC power supply. Other Transmitters and/or a
chart recorder may be connected in series.
1. Insert positive loop wire from power supply to pin 1, tighten screw.
2. Insert negative loop wire to pin 2, tighten screw. This wire may be linked to
a chart recorder or to negative terminal of power supply.
Alpha pH500 Power Supply
Chart recorder
1
2
2.2 Connecting the Electrode and Temperature Probe (SL1
Position)
2.2.1 To connect the pH or ORP electrode:
The pH transmitter accepts any combination
electrode for pH or ORP measurements
1. Remove BNC connector from cable.
Two wires will be exposed.
2. Strip insulation, just enough to expose bare wires.
IMPORTANT: For pH/ORP sensing cable, remember to strip the inner black
layer (screen) and expose the clear plastic sheath.
1. Insert pH sensing cable into pin 1 of connector. Tighten screw.
2. Insert pH reference cable into pin 2 of connector. Tighten screw.
NOTE: Instead of removing the BNC connection, Oakton offers an optional
adapter (part number 05994-90 BNC to Spade Lug adapter) that can be
used.
Insulation
pH reference
Clear sheath
pH sensing
Screen

Instruction Manual pH 500
- 4 -
2.2.2 To connect temperature probe:
For Automatic Temperature Compensated (ATC) pH readings, a 100ΩPt RTD
temperature probes can be used. Industrial pH electrodes are often offered with
ATC, which will typically be bare wires.
3-wire probe
1. Insert Pt 100 sense wire to pin 5 of connector. Tighten screw.
2. Insert Pt 100 input wire to pin 6 of connector. Tighten screw.
3. Insert Pt 100 return wire to pin 7 of connector. Tighten screw.
2-wire probe:
1. Take a small length of wire and short pins 5 and 6 of connector. Insert Pt
100 sense wire into pin 6 of connector and tighten screws.
2. Insert Pt 100 return wire to pin 7 of connector. Tighten screw.
IMPORTANT: Temperature probe should always be together with pH probe,
even during calibration. Make sure no bare wires are exposed and all screws
are tightened for proper contact.
2.2.3 To connect Potential Matching Pin (Liquid electrical interferences):
Connect the additional wire from the electrode to pin 8. Transmitter must be
configured to ‘Symmetrical mode of operation’ - Please refer to ‘Advanced Setup
Functions’, Section 6.6.2 – Selecting Asymmetrical or Symmetrical Mode of
Operation.

Instruction Manual pH 500
- 5 -
3 INSTALLATION
3.1 Wall Mount

Instruction Manual pH 500
- 6 -
3.2 Panel Mount
1. Prepare panel cut-out of
92.0 mm by 92.0 mm
2. Remove back cover of
transmitter and slide it
through panel cut-out
Panel (side)
3. Attach lugs to either
side of transmitter
4. Thread rods through
lugs until transmitter
is held in place against
panel

Instruction Manual pH 500
- 7 -
4 DISPLAY AND KEYPAD FUNCTIONS
4.1 Display
The LCD has a primary and secondary display.
•The primary display shows the measured pH, mV or Relative mV value.
•The secondary display shows the measured temperature. In Calibration
mode, pH buffer values are displayed here; while measured mV values are
displayed in the ORP Calibration mode.
SETUP MEAS CAL
HOLD
pH
°C
READY
-.8.8.8
-1.8.8.8
ATC
pH
mV
ERR
123
4
5
6
7
8
9
10
1112
13
14
15
1. SETup mode indicator 6. Primary display 11. ERRor
indicator
2. MEASurement mode
indicator 7. Temperature indicator 12. Probe
indicator
3. CALibration indicator 8. pH buffer selection indicator 13. Buffer
indicator
4. mV indicator 9. Automatic Temperature
Compensation indicator
14. HOLD
indicator
5. pH indicator 10. Secondary display 15. READY
indicator

Instruction Manual pH 500
- 8 -
4.2 Keypad
The four-button keypad allows easy and quick operations of the Transmitter.
Key Function
CAL Brings you directly into the Calibration mode.
If you were in pH Measurement mode, press CAL to enter pH Calibration
mode.
If you were in mV Measurement mode, press CAL to enter mV Calibration
mode.
▲/ ▼To scroll through the various submenus
To increment/decrement values or toggle between options (in the
SETUP/CAL modes)
When pressed together, serves as escape function to return to MEAS mode
from any point (CAL or SETUP modes).
ENT To confirm your calibration values in Calibration mode.
To confirm selections in SETUP mode.
While in MEAS mode, pressing ENT takes you directly to SETUP submenu

Instruction Manual pH 500
- 9 -
5 CALIBRATION
5.1 Preparing the Transmitter for Calibration
Before starting calibration, make sure you are in the correct measurement mode.
When you switch on the transmitter, the transmitter starts up in the units last used.
For example, if you shut the transmitter off in “mV” units, the transmitter will read
“mV” units when you switch the transmitter on.
Be sure to remove the protective electrode storage bottle or rubber cap of the
electrode before calibration or measurement. If the electrode has been stored dry,
wet the electrode in tap water for 10 minutes before calibrating or taking readings to
saturate the pH electrode surface and minimize drift.
Wash your electrode in deionized water after use, and store in electrode storage
solution. If storage solution is not available, use pH 4.01 or 7.00 buffer solution.
Do not reuse buffer solutions after calibration. Contaminants in the solution can
affect the calibration, and eventually the accuracy of the measurements.
The transmitter features two internationally recognized buffer standards. Select the
buffer standard you require in the CAL mode Select from the following buffer
options:
•First-point: pH 7.00 (USA buffer) or pH 6.86 (NIST buffer).
•Second point: pH 4.01, 9.18, or 10.1.
NOTE: When transmitter is entered into the CAL mode, the 4/20 mA output
current will be automatically held. ‘HOLD’ will be displayed on LCD. After
Calibration and transmitter is returned to MEAS mode, the ‘HOLD’ is
automatically released. Please refer to page 17, section 6.4 for more details.

Instruction Manual pH 500
- 10 -
5.2 pH Calibration
A complete 2-point CAL is required for this Transmitter. If Calibration is aborted
after 1st calibration point, transmitter reverts to previous Calibration data.
1. Rinse probe thoroughly with de-ionized water or a
rinse solution. Blot excess liquid.
2. Dip probe into calibration buffer. End of probe
must be completely immersed into buffer. Stir
probe gently to create a homogeneous sample.
3. From pH MEAS mode, press CAL to enter pH
calibration mode. CAL indicator will be shown.
Primary display will show measured reading while
secondary display will indicate the pH standard
buffer solution.
4. Press ▲or ▼keys to select either pH 7.00 (USA)
or pH 6.86 (NIST) standard buffers. This is the first point, Offset
calibration.
5. Wait for measured pH value to stabilize. Press
ENTER to confirm calibration. Transmitter is now
calibrated to current buffer.
6. Rinse probe with de-ionized water or rinse
solution, and place in next pH buffer (pH 4.01,
pH 9.18 or pH 10.01).
7. Repeat steps 5 and 6.
8. Upon successful Calibration, transmitter displays
Slope (primary display, in mV) and Offset
(secondary display, in pH) of electrode.
9. Press ENTER to return to MEAS mode.
Transmitter has been calibrated. Rinse electrode
and proceed with measurements.
NOTES:
To exit from pH calibration mode without confirming calibration, press ▲and ▼
keys together.
If selected buffer value is not within ±1.0 pH from measured pH value: electrode
and buffer icon blink and ERR annunciator appears in lower left corner of display.
CAL
HOLD
pH
READY
.
.
pH
CAL
HOLD
pH
READY
.
.
pH
CAL
HOLD
pH
READY
.
.
pH
CAL
HOLD
pH
.
.
mV

Instruction Manual pH 500
- 11 -
5.3 Relative mV Calibration
1. From the ORP MEAS mode, press CAL key.
CAL indicator appears at top of LCD. Primary
display shows relative mV reading and
secondary display shows absolute mV value.
2. NOTE: If you have never calibrated relative mV
or if the transmitter has been reset, the value
shown in the primary display is the same as the
absolute mV value.
3. Press ▲or ▼keys to enter the relative mV
value that matches your desired reading (only
the readings in the primary display changes).
4. Press ENTER key to confirm. Transmitter will
now display the offset in the readings.
5. Press ENTER key to return to MEAS mode.
5.4 Temperature Calibration
Temperature calibration is available only in the pH measurement mode and when
ATC probe is available.
Calibrate temperature probe only if temperature value displayed on transmitter is
different from that of a calibrated thermometer. Please refer to section 6.3.1 for
further information.
CAL
HOLD
READY
R.mV
CAL
HOLD
READY
CAL
HOLD
READY
R.mV
R.mV

Instruction Manual pH 500
- 12 -
SETUP
HOLD
SETUP
HOLD
pH
READY
.
.
pH
6 ADVANCED SETUP FUNCTIONS
The advanced setup mode lets you customize your transmitter’s preferences and
defaults. This transmitter features different sub groups that organize all setup
parameters.
The sub-groups are:
6.1 Offset Setting (Unavailable in ORP mode)
As a result of the continuous measurement and the application concerned, it may
not be convenient to remove the electrode for calibration. In such cases, an on-line
Offset adjustment is offered.
1. Press ENT key. Transmitter displays ‘OFS’. Press
ENT again. Upper display shows amount of
offset, in terms of pH; lower display shows current
measured pH value.
2. Use ▲or ▼keys to introduce offset to pH
readings. As the lower measured reading
changes, upper display records the amount of
offset. Maximum of ± 2.00 pH offset is allowed.
3. Press both ▲or ▼keys together to return to ‘
MEAS ‘ mode.

Instruction Manual pH 500
- 13 -
SETUP
HOLD
6.2 Output Range Setting
Output of pH 500 transmitter is via the 2-wire power supply
loop. Both the 4 mA and 20 mA output can be assigned to
specific pH or ORP values, for a more refined output.
1. Press ENT key and use ▲or ▼keys to scroll till LCD
displays ‘r n g ’. Press ENT again. Upper display
shows pH value, ‘0.00 pH’ (or – 1000 mV) while lower
display shows ‘r 4.0’. This is the set up page for the
pH or ORP output range setting for the 4mA output
current.
2. Assign pH or ORP value to 4 mA output current. Use
▲or ▼keys to change pH or ORP value. Press ENT
to accept value.
3. Upper display shows pH value,’14.00 pH’ (or 1000 mV) while lower display
shows ‘r 20.0’. This is the set up page for the pH or ORP output range
setting for the 20mA output current.
4. Assign pH or ORP value to 20 mA output current. Use ▲or ▼keys to
change pH or ORP value. Press ENT to accept value.
5. Press both ▲or ▼keys together to return to ‘ MEAS ‘ mode.

Instruction Manual pH 500
- 14 -
6.3 Temperature Compensation Setting
(Unavailable in ORP mode)
pH values other than pH 7.00 are affected by temperature. Under varying
temperature conditions, use ATC to compensate pH values. If temperature of bath
is constant, and a temperature probe is not available, Manual Temperature
Compensation can be utilized.
6.3.1 Automatic Temperature Compensation
For automatic temperature compensation (ATC), connect ATC probe to transmitter,
as described in Section 2.2.2.
1. Press ENT key to enter SETUP mode. Press ▲or ▼keys to scroll
through sub-menus till LCD displays ‘SET oC’. Press ENT.
2. Display shows ‘ATC On’ or ‘ATC Off’. Use Sor Tkeys to select ‘ATC
On’, and press ENT.
3. Dip ATC probe into a solution of known temperature (i.e. a temperature
bath). Allow time for temperature probe to acclimatize with surrounding
bath temperature. If temperature readings are inaccurate, calibrate
temperature probe as described in steps 4 and 5.
If temperature readings are correct, press ENT key and go to step 6.
4. Use Sor Tkeys to adjust correct temperature value (i.e. temp. of temp.
bath). Readings can be adjusted in increments of 0.1 °C. Maximum
adjustments allowed is ± 5 oC.
5. Once you have adjusted the correct temperature, press ENT key.
6. Press Sand Tkeys together, to return to MEAS mode.
The ATC indicator will light up on the LCD.
NOTE: If you are using a temperature probe, the probe must be submersed in the
liquid you are measuring.
6.3.2 Manual Temperature Compensation
1. Make sure the transmitter is on. Press ENT key and use ▲or ▼keys to
select ‘SET oC’.

Instruction Manual pH 500
- 15 -
2. Press ENT key. Primary display shows ‘ATC’ and secondary display
shows ‘On’ or ‘OFF’. Use ▲or ▼keys to select ‘ATC Off’. Press ENT.
3. Primary display shows temperature (default is 25.0), and secondary
display shows ‘P °C’’. This is the set up page for setting the temperature of
your transmitter to the temperature of your process or sample by using an
accurate thermometer as reference.
4. Use ▲or ▼keys to set the transmitter to the temperature of your process
or sample. Press ENT key.
5. Primary display shows temperature (default is 25.0), and secondary
display shows ‘C °C’. This is the set up page to input to your transmitter
the temperature of your calibration solutions.
6. Use ▲or ▼keys to set the transmitter to the temperature of your
calibration solutions. Press ENT key.
7. Press Sand Tkeys together, to return to MEAS mode.
The transmitter will now compensate pH readings for the manually set temperature
(values taken from P °C’).

Instruction Manual pH 500
- 16 -
SETUP
HOLD
SETUP
HOLD
SETUP
HOLD
°C
.
.
ATC
SETUP
HOLD
SETUP
HOLD
.
SETUP
HOLD
.
Temperature Compensation Setting Chart – alpha pH 500 Transmitter

Instruction Manual pH 500
- 17 -
SETUP
HOLD
SETUP
HOLD
SETUP
HOLD
6.4 HOLD Current Setting
When Transmitter is in CAL or SETUP modes, it automatically
goes into a ‘HOLD’ mode.
To indicate Transmitter is in ‘HOLD’ mode, output current can be
set to 22 mA output by activating the ‘HLD On’.
1. Press ENT key and use ▲or ▼keys to scroll till LCD
displays ‘SEt’ in the upper display; and ‘HLd’ in the
lower display. Press ENT again.
2. Upper display now shows ‘HLd’. Lower display will
show either ‘OFF’ or ‘On’. Use ▲or ▼keys to toggle
between ‘On’ of ‘OFF’. Press ENT to accept selection.
3. Press Sand Tkeys together, to return to MEAS
mode.
NOTE: If ‘HLd’ is set to ‘OFF’, then current output will be
equivalent to last measured value.
6.5 Out-of-Range Current Setting
If pH or ORP readings exceed the scale, LCD displays ‘Or’ (over-
range), or ‘Ur’ (under-range). Transmitter current output can be
set to 3.8 mA to indicate Out-of Range situation.
1. Press ENT key and use ▲or ▼keys to scroll till LCD
displays ‘SEt’ in the upper display; and ‘org’ in the lower
display. Press ENT again.
2. Upper display now shows ‘org’. Lower display will show
either ‘OFF’ or ‘On’. Use ▲or ▼keys to toggle
between ‘On’ of ‘OFF’. Press ENT to accept selection.
3. Press Sand Tkeys together, to return to MEAS mode.
NOTE: If ‘org’ is set to ‘OFF’, under-range will be set at 4 mA,
while over-range will be set at 20 mA.
SETUP
HOLD
SETUP
HOLD
SETUP
HOLD