jenway 370 User manual
370 350/REV A/10-03
MODEL 370 pH/mV METER
OPERATING MANUAL
MODEL 370
pH/mV METER
OPERATING INSTRUCTIONS
CONTENTS
Introduction 1
Specification 1
Installation 2
Displays 2-3
Controls 4
Operation 5
Calibration 5-7
Error Codes 8
mV Mode 8-9
Manual Temperature Compensation 9
Auto Shut Off 9
Data Storage 10
Good Practice Guidelines 11
Maintenance 12
Troubleshooting Guide 13-14
Checking pH Electrode Function 14
Checking pH Meter Function 15
Checking Temperature Input 15
Battery Replacement 16
Optional Accessories 16
Spare Parts 16
EC Declaration of Conformity 17
MODEL 370
pH/mV METER
OPERATING INSTRUCTIONS
INTRODUCTION
The Model 370 is a general purpose hand held pH/mV meter
offering a 1 or 2 point calibration and automatic buffer recognition
with manual override. The custom liquid crystal display
simultaneously shows temperature compensated pH readings or
electrode potential and temperature. The instrument is housed in a
robust, ergonomically designed case. Calibration errors are clearly
indicated together with the parameter in error. An indication of
battery life is also permanently shown on the display. An
automatic switch off facility helps to conserve battery life.
SPECIFICATION
pH (1 or 2 point cal)
Range: -2 to 16.00pH
Resolution/Accuracy: 0.01pH / ±0.02pH
mV (Absolute or Relative)
Range: -1999 to +1999mV
Resolution/Accuracy: 1mV / ±1mV
Temperature Ranges: -10 to +105°C / 14 to 221°F
Resolution/Accuracy: 0.1°C / ±0.5°C / 1°F / ±1°F
ATC Range: 0 to 100°C / 32 to 212°F
Manual Temp. Comp. Range: 0 to 100°C / 32 to 212°F
Auto Buffer Recognition: 4.00, 7.00, 9.22, 10.00
(manual override)
Calibration: User selectable 1or 2 pt
Power: 2 AA cells
Battery Life: 500 hours typical
(@ 25°C with alkaline cells)
Size: 175(l)x75(w)x35(d)mm
Weight: 250g
1
INSTALLATION
Unpack the instrument and ensure the following items are present:
1. Model 370 pH/mV Meter (370 201)
2. Epoxy bodied combination pH electrode (924 001)
3. Temperature/ATC probe (027 500)
4. pH4, 7 & 10 buffer sachets
5. 2 x AA alkaline batteries (021 007)(fitted)
Optional accessories which may have been ordered:
1. Carrying Case (033 268)
1. Main display - 3½ digit display providing direct readout of
pH or mV. Underrange (-1) and Overrange (1) symbols will
be displayed if the instrument is reading outside the
ranges of:
pH -2.00 to 16.00 or mV -1999 to +1999
In addition, the instrument will display an erroneous
result momentarily at the same time as the secondary
display indicates the error code.
DISPLAYS
2
3
2. Secondary display - 4 digit display showing
temperature (manual temperature compensation value or
ATC probe temperature, if connected) in °C or °F. In the
event of a calibration error the display will show an
error code momentarily (if the reading is outside the
range of -10 to 105°C / 14 to 220°F) at the same time as
the primary display indicates the erroneous reading.
These codes will be shown as Err1, Err2 or Err3.
3. CAL 1 or CAL 2 indicator - shows which point of the
calibration routine has been reached.
4. Battery Life Indication - 4 levels will be shown ranging
from <25%, 25-50%, 50-75% and 75-100%. Sensor
calibration data and user parameters are retained during
battery replacement.
5. Mode annunciator - pH or mV is displayed depending on
which mode of operation is selected.
6. REL - this is the relative mV mode annunciator. The
relative mV mode is selected via the Cal key. If the mV
mode is selected and this annunciator is not shown then
the instrument is reading in absolute mV.
7. MAN - this is displayed to indicate when manual
temperature compensation or manual pH calibration is
being performed. This will not appear on the display
when the ATC probe is connected.
8. RCL annunciator - this indicates that the displayed
reading is the stored value recalled from memory.
KEYPAD CONTROLS
STO RCL STO stores the current data reading.
RCL enters recall mode to view the stored
readings.
I:O Switches the instrument on and off. This key
should be pressed and held for 1-2 seconds to
operate. The instrument will automatically switch
off after 30 minutes if no key is pressed.
Back light. Pressing this key will illuminate the
back light for 10 seconds. It should be noted
that, if used excessively, this will reduce battery
life.
Enables manual setting of pH buffer values when
performing a calibration, and adjustment of the
manual temperature compensation value (no ATC
probe connected).
CAL This key is used to select and perform
calibration in the pH mode. In the mV mode
pressing the Cal key will toggle between Absolute
and Relative mV.
MODE This key changes the measurement parameter
to pH or mV mode as required and sets to °C/°F.
Press and hold for 3 seconds to select temperature
unit.
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4
OPERATION
Switch the instrument on by holding down the I/O key for 1-2
seconds. All display segments will be illuminated for approximately
2 seconds. The display will either power up in the mV or pH mode
depending upon previous usage. An internal self check routine is
run during this display and on successful completion normal
operating mode is activated.
If no ATC probe is connected to the instrument the MAN
annunciator will be shown. Manual temperature compensation
should always be entered prior to commencing a calibration.
Remove the electrode from the packaging and ensure it is in good
condition. Connect the electrode to the instrument via the BNC
socket and remove the wetting cap. Prior to performing pH
measurement it is necessary to perform a 1 or 2 point calibration
using the buffer sachet(s) provided. Connect the ATC probe (if
being used) to the mini-DIN socket and immerse the ATC probe in
the pH buffer alongside the pH probe.
CALIBRATION
The 370 features a one or two point calibration. For the best
results we recommend that the 370 is calibrated with buffer
solutions that are close to the sample value, where possible. For
example: when working at pH5.5 we recommend calibrating at
pH7 and pH4.
Auto buffer recognition operates over the range of 0 to 100°C,
and will recognise 4.00, 7.00, 9.22 and 10.00pH. Alternative
manual values may be entered during the calibration sequence by
using the keys to set the preferred values.
NOTE:Manual temperature compensation (if being used) should
be entered prior to commencing a calibration sequence using the
keys. (If the displayed reading is altered the auto buffer
5
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Select pH using the MODE key. To commence the calibration
immerse the tip of the electrode and the ATC probe into the first
buffer solution so that the bulb and reference junction are
covered.
AUTOMATIC CALIBRATION FIRST POINT
Press the CAL key and the display will show the CAL1
annunciator. The primary display will show a reading close to the
buffer value based on the last successful calibration.
For automatic calibration to one of the pre-programmed buffer
values wait for the reading to stabilise and then press the CAL
key again to update the display to the temperature corrected value
for the buffer used (refer to the buffer value tables on buffers
used).
If a one point only calibration is required, pressing the MODE key
will return the display to the pH measurement mode. The
instrument is then ready to perform sample measurements.
AUTOMATIC CALIBRATION SECOND POINT
If a two point calibration is required the electrode should be rinsed
and then immersed in the second buffer solution.
6
recognition feature will be disabled. To retrieve the auto buffer
recognition values it is necessary to exit the calibration sequence
by pressing the MODE key).
To exit the cal sequence at any point, press the MODE key.
Rinse electrode(s) in deionised water between
measurements.
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MANUAL CALIBRATION SECOND POINT
If a two point calibration is required the electrode should be rinsed
and then immersed in the second buffer solution.
For manual calibration press the keys to change the reading
to the value for the specific buffer being used. When the correct
value is achieved press the CAL key again to confirm this value.
CALIBRATION COMPLETE
For both automatic and manual calibration procedures the last
(3rd) press of the CAL key returns the display to the pH
measurement mode and sample measurement can proceed.
7
MANUAL CALIBRATION FIRST POINT
Press the CAL key and the display will show the CAL1
annunciator. The primary display will show a reading close to the
buffer value based on the last successful calibration.
For manual calibration press the keys to change the reading
to the value for the specific buffer being used. When the correct
value is achieved press the CAL key again to confirm this value.
The primary display will show a reading close to the buffer value
based on the last successful calibration. For automatic calibration
to one of the pre-programmed buffer values wait for the reading
to stabilise and then press the CAL key again to update the display
to the temperature corrected value for the buffer used (refer to
the buffer value tables on buffers used).
ERROR CODES
Refer to Troubleshooting Guide for possible causes of error
codes. If a problem is detected during calibration the following
error codes will be displayed:
Err1 This indicates that the calculated electrode offset at pH7 is
outside the range of -30 to +30mV. The error code will be
displayed for 3 seconds on the secondary display, together with
the erroneous electrode offset value in mV on the primary display.
The instrument will then reset the calibration data back to the ideal
Nernst response of 0mV offset at 7pH and a slope of 59.16mV/pH
at 25°C.
Err2 This indicates that the slope value is out of range. The
error code will be displayed for 3 seconds on the secondary
display, together with the erroneous value as a % on the primary
display. The instrument will then reset the calibration data back to
the ideal Nernst response of 0mV offset at 7pH and a slope of
59.16mV/pH at 25°C. The allowable range for slope is 75 to 125%
of the ideal Nernst figure.
Err3 This indicates that the instrument has not recognised the
buffer. The displayed reading must be within 1pH of the calibration
buffer value for automatic buffer recognition. The error code will
be displayed for 3 seconds on the secondary display, together
with the erroneous pH buffer value on the primary display. The
instrument will then reset the calibration data back to the ideal
Nernst response of 0mV offset at 7pH and a slope of 59.16mV/pH
at 25°C.
mV MODE - Absolute mV
When this mode is selected the instrument will display the actual
voltage developed by the electrode when it is immersed in a
solution containing ions to which the electrode is sensitive.
Combination type pH, redox and ion selective electrodes can all be
used in this mode. Most of these determinations will require the
preparation of calibration curves or other analytical methods for
the results to be converted to a concentration unit.
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