Extech Instruments ExStik EC500 User manual

User Manual
ExStik®EC500
pH / Conductivity / TDS / Salinity / Temperature Meter
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Introduction
Congratulations on your purchase of the ExStik® EC500 pH/Conductivity/Total Dissolved Solids
(TDS) / Salinity meter. With the EC5 -constant technology it is possible to measure
a wide range of Conductivity, TDS, and Salinity with the same electrode. Careful use and
maintenance will provide years of reliable service.
The ExStik® uses four (4) CR2032 Lithium Ion Batteries
indicator appears on the LCD. Press the ON/OFF key to turn the ExStik® on or off. The auto power
off feature shuts the ExStik® off automatically after 10 minutes of inactivity to preserve battery life.
Getting Started
Remove the cap from the bottom of the ExStik to expose the pH electrode, reference junction
and conductivity electrodes.
Before the first use or after storage, soak the electrode in tap water or pH 4 buffer solution for
about 10 minutes.
White KCL crystals may be present in the cap or on the electrode. This is to be expected
depending on the length of time in storage. These crystals will dissolve while soaking the
electrode or they can be rinsed away with tap water.
For best results calibrate with pH 7 buffer solution first, then calibrate with the buffer solution
closest to the expected pH value of the solution or material to be tested.
To preserve the pH electrode life, keep the sponge in the protective cap soaked with tap water
or pH 4 buffer solution.
For best results, calibrate for conductivity with a standard in the expected range of the sample.
For maximum accuracy calibrate from low conductivity value standards to high value standards.
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Meter Description
Front Panel Description
1. Battery compartment cover
2. LCD Display
3. MODE/HOLD button
4. CAL/RECALL button
5. ON/OFF button
6. Electrode Collar
7. pH/Conductivity Electrode
(Note: The Electrode cap is not shown)
LCD Display
1. Bargraph display
2. Measurement units
3. Main display
4. Range calibration and
low battery indicators
5. Temperature display
6. Renew indicator
7. Reading hold indicator
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Measurement Procedure
Sample Preparation:
1. For Conductivity, TDS or Salinity place the test sample in a sample
cup with enough depth (2.5cm minimum) to cover the electrode. Stir
the solution to remove any air bubbles.
2. For pH, place the tip of the electrode in the sample or make contact
with a wet surface.
Measurement:
1. Press the ON button. (
display during the turn-on diagnostics)
2. Depress and hold the MODE/HOLD key to scroll to the desired
measurement mode.
3. Insert the electrode into the sample making sure that the electrodes are
completely submersed.
4. Slowly stir the solution with the electrode to remove air bubbles if in the
Conductivity, TDS or Salinity mode.
5. If in the Conductivity, TDS or Salinity modes, the meter will auto-range
to the proper range and then display the reading.
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Changing Measurement Function
The meter can be set to measure pH, Conductivity, TDS or Salinity.
To change the mode:
1. Press and Hold the MODE/HOLD button for 2 seconds and the display will begin to scroll
through the units.
µS (Conductivity); pH; ppm S (Salinity); ppm (TDS); mg/l (TDS);
Note:
displayed in the lower left corner of the display, briefly press the MODE/HOLD button to turn it off.
2. When the desired units are displayed, release the MODE/HOLD button.
TDS Compensation Ratio
The TDS value is determined by multiplying a conductivity reading by a known ratio factor. The
meter allows for selecting a conversion ratio in the range of 0.4 to 1.0. The ratio varies with the
application, but is typically set between 0.5 and 0.7.
Note: The stored ratio will briefly appear in the lower temperature display when the meter is first
turned on, or when changing measurement function to TDS.
Note: In the Salinity mode the ratio is 0.4 to 0.6 auto
To change the ratio, while in the TDS measurement mode (ppm or mg/l):
1. Press and release the CAL/RECALL button twice in succession. The stored
ratio will appear in the display.
2. Press the MODE/HOLD button to increase the ratio value in steps of 0.1.
3. When the desired ratio is displayed, press and release the CAL/RECALL
button to store the value and return to the normal mode.
4. If no buttons are pressed for 5 seconds, the meter returns to measure mode.
Storing Readings
1. Press the MODE/HOLD button to store a reading. The storage location
number will be displayed on the lower display, while the main display shows
the stored reading. The meter will enter the HOLD mode and the
indicator will appear.
2. Press the MODE/HOLD button again to exit the HOLD mode and return to
normal operation.
3. If more than 25 readings are stored, previously stored readings (starting with
number 1) will be overwritten.
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Recalling Stored Readings
1. Press the CAL/RECALL button and then press the MODE/HOLD button. A location number (1
through 25) will briefly appear and then the value stored in that location will appear. The
displayed units will flash, indicating that the storage recall mode is active.
2. The last stored reading will be displayed first. Pressing and releasing the MODE/HOLD button
will scroll through the stored readings one at a time. The location number is displayed first,
followed by the reading stored in that location.
3. To exit the storage mode, press the CAL/RECALL button and the meter will return to normal
operation nd .
Clear Stored Memory
clr
memory is cleared.
Changing Temperature Units
To change the displayed temperature units (oC or oF):
1. With the unit OFF, press and hold down the CAL/RECALL button.
2. With the CAL/RECALL button depressed momentarily press the ON/OFF button.
CAL/RECALL button. The unit will power on with
temperature displayed in the new units.
Data Hold Mode
Press the MODE/HOLD button to hold (freeze) a reading in the display. The meter will enter the
Note: This also stores the reading.
Press the MODE/HOLD button again to return to normal operation.
Auto Power OFF
The auto power off feature automatically shuts the meter off 10 minutes after the most recent button
press.
Auto Power OFF Disable
To disable the Auto Power Off feature:
1. Turn the unit on
2. Press CAL/RECALL once (Quickly)
3. Immediately and simultaneously press the MODE/HOLD and ON/OFF buttons for
approximately 2 seconds, until oFF is briefly displayed
To disengage this feature, turn the unit off with the ON/OFF button. The next time the unit is
powered up, Auto Power OFF mode will be engaged again.
Low Battery Indication
on will appear in the display. Refer to the
Maintenance section for battery replacement information.
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Calibration - pH (1, 2, or 3 points)
1. Place the electrode into a buffer solution (4, 7, or 10). Press and hold the CAL/RECALL key
. When doing a 2 or 3 point calibration, calibrate
with pH 7 buffer first, then follow with pH 4 then the pH 10 buffer.
2. The ExStik® automatically recognizes the solution and calibrates itself to that value (the circled
number on the LCD will match the solution). Note that if the solution is more than 1 pH unit off
from the L (4), M (7), or H (10) pH buffer, or if the electrode slope is low, the ExStik®will
assume an error and abort the calibration ( will be displayed, and the unit will return to
measure mode.)
3. During calibration, the pH reading flashes on the main display.
4. When calibration is complete, the ExStik® automatically displays nd and returns
to normal operation mode.
5. The appropriate circled indicator (L, M, or H) appears on the LCD when a particular calibration
or series of calibrations has been completed within one power on cycle. When the ExStik® is
turned off, the circled indicator configuration and the calibration data will be retained.
6. For a two or three-point calibration, repeat steps 1-4.
7. See Reset Calibration Data to clear all calibration data from the meter.
CAL Reminder Display
When in pH measurement mode, without
performing a calibration. The CAL display is simply a reminder to calibrate pH, and will turn off when
the pH electrode is recalibrated. The reminder does not affect function in any way.
RENEW Display
is not performing to expected specifications. If
cleaning and recalibration does not cause the RENEW icon to disappear, replace the probe (see
optional accessories on the last page of this manual). The RENEW display appears as a result of
the pH electrode slope falling below 70% of a nominal slope.
Measurement and Display Considerations
If the unit appears to be locked (display frozen). It is possible that the Data Hold mode has
been inadvertently accessed by pressing the MODE/HOLD button.
in the bottom left of the LCD.) Simply press the MODE/HOLD button again or turn the meter off
and then on.
For maximum accuracy, allow sufficient time for the temperature of the probe to reach the
temperature of the sample before calibrating. This will be indicated by a stable temperature
reading on the display.
Reset Calibration Data
Follow this procedure to clear all calibration data from the meter. Resetting the calibration data may
be necessary when new calibration solutions are used or accuracy of measurements is in question.
1. Turn off the meter.
2. Press and Hold the Cal/Recall and Mode/Hold buttons.
3. Momentarily press the On/Off button, as soon as the display comes on, release all 3
buttons.
4. The display will show dFLt rSt ration data will be erased.
If does not appear, retry the procedure.
5. Proceed to the calibration routine for pH and Conductivity.
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Calibration - Conductivity
Meter accuracy verification should be performed on a periodic basis. Once per month is the
recommended cycle for normal use. If calibration is required, a conductivity standardizing solution
must be obtained. The meter can be calibrated in any or all of the three ranges. Standardizing
solutions of 84µS/cm, 1413µS/cm or 12.88mS/cm (12,880µS/cm) are used for the automatic
calibration recognition procedure. No other calibration values are permitted.
Calibration is always done in conductivity mode. Since salinity and TDS values are calculated from
conductivity values, this procedure also calibrates the salinity and TDS ranges.
1. Fill a sample cup with the standardizing solution.
2. Turn the meter ON and insert the electrode into the solution. Tap or move the electrode in the
sample to dislodge any air bubbles.
3. Press and hold the CAL/RECALL button (approximately 2 seconds) until s in
the lower (temp) display. The main display will start flashing.
4. The meter will automatically recognize and calibrate to the standardizing solution. The display
will brie nd and then return to the measurement mode after a calibration.
5. range ange that is calibrated
during that power on cycle.
Low range, 84µS/cm
Medium range, 1413µS/cm
High range, 12.88mS/cm (12,880µS/cm)
Note: Each time the calibration mode is entered all calibration symbols on the display are cleared,
but only the calibration data for the currently calibrated range is replaced. The other two ranges
keep the existing calibration data, just the symbols are removed. Calibration of all three ranges must
be performed during one power on period for all three range calibration symbols to appear.
See Reset Calibration Data to clear all calibration data from the meter.
Note: The meter allows for a 1, 2 or 3 point calibration. If calibration is done for more than one point
the lowest value standard should be done first to obtain the best accuracy.
Considerations and Techniques
Do not touch the inner surfaces of the conductivity electrodes. Touching the surface of the
platinized electodes may damage and reduce the life of the probe.
Store the electrode in the wetting cap with the sponge moistened with pH 4.01 buffer solution.
Always rinse the electrode in de-ionized water between measurements to avoid cross
contamination of the sample. Double rinsing is recommended when high accuracy is required.
Periodically, accumulated salt deposits from the reference electrode may build up in the
storage cap, and should be rinsed away. These deposits could affect measured values of low
conductivity samples.
When measuring low conductivity samples, extra care is recommended in rinsing the probe to
avoid contamination of the sample with electrolyte from the pH reference electrode. This will
only be a factor when measuring in the low range, and can be further minimized by increasing
the volume of the sample. (Example: Try a 200 to 500 mL sample.)
If the 20mL sample cup is to be used, then the electrode should not be allowed to sit in the
sample for any longer than necessary, to avoid pH electrolyte leakage into the sample, raising
the conductivity value.
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Operational Matrix
Function /
Resulting Action
Power
Status
Mode
Setting
Required Key Press Sequence
On/Off On or Off Any Momentary press of the ON/OFF key
Calibration On pH or
Conductivity
Press & hold CAL/RECALL key for 2
seconds, until it enters CAL function
Store Reading On Any measure
mode
Momentary press of the
MODE/HOLD key
Hold Release On While In Hold
Mode
Momentary press of the
MODE/HOLD key
Enter Memory
Retrieval
On Any measure
mode
Momentary press of the
CAL/RECALL key followed by a
momentary press of the
MODE/HOLD key (Within 4 seconds)
Scroll Stored
Readings
On Memory
Recall
Momentary press of the
MODE/HOLD key
(Displays last in first out )
Exit Memory
Retrieval
On Memory
Recall
Momentary press of the
CAL/RECALL key
Clear Stored
Memory
On Any Measure
Mode
Press and hold the ON/OFF key for 4
seconds
Change
Measurement Mode
On Any Press and hold the MODE/HOLD key
for at least 2 seconds (the modes will
scroll by until the key is released)
Enter Cond/TDS
Ratio
On TDS (ppm or
mg/l)
Press and release the CAL/RECALL
key twice in quick succession
Change Cond/TDS
Ratio
On TDS ratio Momentary press of the
MODE/HOLD key (each key press
increases the ratio by 0.1, the value
cycles from 0.4 - 1.0)
Exit Cond/TDS
Ratio
On TDS ratio Momentary press of the
CAL/RECALL key
Change
Temperature Units
Off n/a (off
mode)
Press and hold the CAL/RECALL key
then momentarily press the On/Off
key. Release the CAL/RECALL key
after the "SELF CAL" lights
Override Auto
Power Off
On Any measure
mode
Momentarily press the CAL/RECALL
key then simultaneously press and
hold the ON/OFF & MODE/HOLD key
for approximately 2 seconds, until
Default Reset OFF n/a Simultaneously press ON/OFF,
CAL/RECALL and MODE/HOLD
momentarily will be displayed.
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Specifications
Display 2000 count LCD with Bargraph
pH Range 0.00 to 14.00
pH Accuracy ±0.01 pH typical
pH ATC Range 32°F to 194oF (0°C to 90oC)
pH Reference Junction Permanent gel, non-refillable
Conductivity ranges 0 to 199.9µS
200 to 1999µS
2.00 to 19.99mS
TDS ranges 0 to 99.9ppm or mg/L
(Variable ratio) 100 to 999ppm or mg/L
1.00 to 9.99ppt or g/L
Salinity range 0 to 99.9ppm
100 to 999ppm
1.00 to 9.99ppt
TDS Ratio 0.4 to 1.0 adjustable
Salinity Ratio 0.4 to 0.6 auto
Conductivity ATC 2.0% per oC
Conductivity ATC Range 32.0°F to 140oF (0.0°C to 60.0oC)
Temperature Range 23.0°F to 194oF (-5.0°C to 90.0oC)
Temperature Resolution 0.1 up to 99.9, 1 >100
Temperature Accuracy ±1.8°F; 1°C (from 23 to 122°F;-5 to 50°C)
±5.4°F; 3°C (from122 to 194°F; 50 to 90°C)
Accuracy Conductivity: ±2% full scale
TDS: ±2% full scale
Salinity: ±2% full scale
Measurement Memory 25 tagged (numbered) readings
Low battery indication
Power Four (4) CR2032 Lithium Ion Batteries
Auto power off After 10 minutes (override available)
Operating conditions 23°F to 122oF (-5°C to 50oC)
Dimensions (40 x 200 x 40 mm)
Weight 3.3 oz (93 g)
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