Milwaukee MW150 User manual

INSTRUCTION MANUAL
SATISFACTION
GUARANTEED
MW150 &MW151 MAX
pH / ORP / Temperature
Bench Meters
pH
ATC
CAL
4.01
7.01
10.01
ºC

All rights are reserved. Reproduction in whole or in part is prohibited without the written
consent of the copyright owner, Milwaukee Instruments Inc., Rocky Mount, NC 27804 USA.
THANK YOU for choosing Milwaukee Instruments!
This instruction manual will provide you the necessary information for correct use
of the meters.

3
TABLE OF CONTENTS
1. PRELIMINARY EXAMINATION...................................................................................................................................4
2. INSTRUMENT OVERVIEW ..........................................................................................................................................5
3. SPECIFICATIONS.............................................................................................................................................................6
4. FUNCTIONAL & DISPLAY DESCRIPTION............................................................................................................8
5. GENERAL OPERATIONS.............................................................................................................................................12
5.1. BATTERY MANAGEMENT ................................................................................................................................12
5.2. CONNECTING THE ELECTRODE & TURNING THE METER ON ................................................... 12
5.3. OPERATION OVERVIEW..................................................................................................................................12
6. SETUP.................................................................................................................................................................................14
6.1. GENERAL SETUP.................................................................................................................................................14
6.2. MW151 SPECIFIC SETUP................................................................................................................................18
7. pH ........................................................................................................................................................................................20
7.1. pH PREPARATION................................................................................................................................................20
7.2. pH CALIBRATION................................................................................................................................................20
7.3. pH MEASUREMENT..........................................................................................................................................22
7.4. WARNINGS & MESSAGES ...........................................................................................................................24
8. ELECTRODE CONDITION & MAINTENANCE .................................................................................................. 27
9. ORP .....................................................................................................................................................................................30
9.1. PREPARATION......................................................................................................................................................30
9.2. ORP CALIBRATION...........................................................................................................................................30
9.3. ORP MEASUREMENT......................................................................................................................................30
10. LOGGING (MW151) .....................................................................................................................................................31
10.1. TYPES OF LOGGING.........................................................................................................................................31
10.2. DATA MANAGEMENT.....................................................................................................................................33
11. MEM & MR FUNCTIONS (MW150).....................................................................................................................38
12. GLP....................................................................................................................................................................................39
13. TROUBLESHOOTING..................................................................................................................................................41
14. ACCESSORIES..............................................................................................................................................................42
CERTIFICATION..................................................................................................................................................................43
RECOMMENDATION........................................................................................................................................................43
WARRANTY..........................................................................................................................................................................43

4MW150 & MW151 Bench Meters
1. PRELIMINARY EXAMINATION
Each bench meter is delivered in a cardboard box and is supplied with:
yMA917B/1 pH electrode
yMA831R Temperature probe
yMA9315 Electrode holder
yM10004 pH 4.01 buer solution (sachet)
yM10007 pH 7.01 buer solution (sachet)
yM10010 pH 10.01 buer solution (sachet)
yM10016 Electrode cleaning solution (sachet)
yGraduated pipette
y12 VDC adapter
yUSB cable (MW151)
yInstrument quality certificate
yInstruction manual

INSTRUMENT OVERVIEW 5
2. INSTRUMENT OVERVIEW
MW150andMW151 pH/ORP/Temperaturebenchmetersperformaccuratemeasurements
and present a series of new diagnostic features for improved reliability.
yUp to 3-point (up to 5-point, MW151) automatic pH calibration, 7 standard calibration
buers (pH 1.68, 4.01, 6.86, 7.01, 9.18, 10.01 and 12.45) and two custom buers (MW151)
yAvailable log space for up to 1000 records (MW151)
yAlphanumeric LCD displayed messages for user friendly, intuitive information/
warning/error messages
yBuilt-in rechargeable battery with an 8-hour capacity
yAuto-o feature to prolong battery life
yInternal clock and date to keep track of dierent time-dependent functions (calibration
timestamp, calibration time out)
yDedicated GLP key to store and recall data on system status

6MW150 & MW151 Bench Meters
3. SPECIFICATIONS
Range *
MW150 MW151
pH –2.00 to 20.00 pH –2.00 to 20.00 pH
–2.000 to 20.000 pH
mV ±2000.0 mV ±2000.0 mV
Temp. –20.0 to 120.0 °C (-4.0 to 248.0 °F) –20.0 to 120.0 °C (-4.0 to 248.0 °F)
Resolution
pH 0.01 pH 0.01 pH
0.001 pH
mV 0.1 mV 0.1 mV
Temp. 0.1 °C (0.1 °F) 0.1 °C (0.1 °F)
Accuracy
@ 25°C (77°F)
pH ±0.01 pH ±0.01 pH
±0.002 pH
mV ±1 mV ±1 mV
Temp. ±0.4 °C (±0.8 °F) ±0.4 °C (±0.8 °F)
pH calibration
up to 3-point automatic
7 standard buers (pH1.68, 4.01,
6.86, 7.01, 9.18, 10.01, 12.45)
no custom buers
up to 5-point automatic
7 standard buers (pH1.68, 4.01,
6.86, 7.01, 9.18, 10.01, 12.45)
2 custom buers
Temperature
compensation
Automatic
-20.0 to 120.0°C (-4.0 to 248.0 °F)
Manual
(without temperature probe)
Automatic
-20.0 to 120.0°C (-4.0 to 248.0 °F)
Manual
(without temperature probe)
Log Memory function
Maximum 1000 log records
(stored in up to 100 lots)
Log on demand, 200 logs
Log on stability, 200 logs
Interval logging, 1000 logs
PC connection none 1 USB port, 1 micro USB port
Power supply 12 VDC adapter 12 VDC adapter,
5 VDC USB adapter
Battery life 8 hours
Auto-o 5, 10, 30, 60 min. or o
Environment 0 to 50 °C; max RH 95%
Dimensions 230 x 160 x 95 mm (9.0 x 6.3 x 3.7”)
Weight 0.9 kg (2.0 lb.)
Warranty 3 years
* Limits will be reduced to actual sensor limits

SPECIFICATIONS 7
pH electrode
MA917B/1
pH range 0 to 14 pH
Temperature range  to °C  to  °F
Shaft material glass
Reference electrolyte KCl 3.5M
Reference junction ceramic, single
Reference type double, Ag/AgCl
Maximum pressure 0.1 bar
Connector type BNC
Cable length 1 m
Shaft length 120 mm
Diameter 12 mm

8MW150 & MW151 Bench Meters
4. FUNCTIONAL & DISPLAY DESCRIPTION
Front Panel MW150
1. Liquid Crystal Display (LCD)
2. ESC key, to leave current mode
3. MR key, to recall the stored value
from memory
4. SETUP key, to enter setup mode
5. MEM/CLEAR key, to store the
reading or to clear calibration
or memory
6. First LCD line, measurement
readings
7. Second LCD line, temperature
readings
8. Third LCD line, message area
9. ON/OFF key, to turn the meter ON
and OFF
10.  keys, to change manual
temperature, select setup parameters and choose
calibration buers
11. RANGE/key, to select pH or mV
12. GLP/ACCEPT key, to enter GLP or to confirm selected action
13. CAL/EDIT key, to enter/edit calibration settings, edit setup settings
Rear Panel MW150
14. Power supply socket
15. Reference electrode socket
16. Temperature probe socket
1 7. BNC electrode connector
pH
ATC
CAL
4.01
7.01
10.01
ºC
9
10
11
12
13
6
7
8
1
2
3
4
5
Power
12Vdc
+-
Ref. Temp. pH/ORP
14
15
16
17

FUNCTIONAL & DISPLAY DESCRIPTION 9
Front Panel MW151
1. Liquid Crystal Display (LCD)
2. ESC key, to leave current mode
3. RCL key, to recall the logged values
4. SETUP key, to enter setup mode
5. LOG/CLEAR key, to log the reading
or to clear calibration or logging
6. First LCD line, measurement
readings
7. Second LCD line, temperature
readings
8. Third LCD line, message area
9. ON/OFF key, to turn the meter ON
and OFF
10.  keys, to change manual
temperature, select setup parameters and choose
calibration buers
11. RANGE/key, to select pH or mV
12. GLP/ACCEPT key, to enter GLP or to confirm selected action
13. CAL/EDIT key, to enter/edit calibration settings, edit setup settings
Rear Panel MW151
14. Power supply socket
15. Reference electrode socket
16. Temperature probe socket
1 7. BNC electrode connector
18. USB ports
pH
ATC
CAL
4.01
7.01
10.01
ºC
9
10
11
12
13
6
7
8
1
2
3
4
5
Power
12Vdc
+-
USB
DEVICE
HOSTRef. Temp. pH/ORP
USB
14
18
15
16
17

10 MW150 & MW151 Bench Meters
Display Description MW150
pHmV
NO MTCATC
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
DATE
ACCEPT
ºC
ºF
pH
mV
TIME
1
2
3
6
7
5
4
15
16
14
13
11
8
10
12
9
1. Status information
2. Clear message/calibration/memory
3. OPEN is displayed when the electrode cap has to be removed.
Refill cap is displayed blinking before calibration.
4. Electrode symbol
5. Accept tag
6. Third LCD line, message area
7. Mode tags
8. Oset/slope indicators
9. Second LCD line, temperature measurement
10. Temperature and measurement units
11. Arrow tags, to help user select required information
12. Temperature compensation status (MTC, ATC)
13. pH calibration buers
14. Primary LCD, measurement line
15. Measurement units
16. Stability indicator

FUNCTIONAL & DISPLAY DESCRIPTION 11
Display Description MW151
pHmV
NO MTCATC
USB
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
CUST1
CUST2
DATE
ACCEPT
ºC
ºF
pH
mV
TIME
1
2
7
4
3
8
9
6
5
17
18
16
15
13
10
12
14
11
1. Status information
2. Clear message/calibration/memory
3. USB connections status
4. OPEN is displayed when electrode cap has to be removed.
Refill cap is displayed blinking before calibration.
5. Electrode symbol, filled in segments indicate electrode condition
6. Accept tag
7. Log tag
8. Third LCD line, message area
9. Mode tags
10. Oset/slope indicators
11. Second LCD line, temperature measurement
12. Temperature and measurement units
13. Arrow tags, to help user select required information
14. Temperature compensation status (MTC, ATC)
15. pH calibration buers
16. Primary LCD, measurement line
1 7. Measurement units
18. Stability indicator

12 MW150 & MW151 Bench Meters
5. GENERAL OPERATIONS
5.1. BATTERY MANAGEMENT
When using the meter with battery, please charge the battery of the bench meter fully
before first use.
Use the supplied 12 VDC adapter, or connect to a PC through USB cable (MW151 only) to
recharge your battery.
Note: The instrument is equipped with auto-o feature to preserve battery energy.
5.2. CONNECTING THE ELECTRODE & TURNING THE METER ON
Plug the 12 VDC adapter into the power supply socket.
To prepare the instrument for use, connect the MW917B/1 pH electrode to the BNC connector
and the temperature probe to the appropriate socket on the rear panel of the instrument.
The temperature probe can be used in conjunction with the pH electrode to utilize the
instrument’s ATC capability, but can also be used independently to take temperature
measurements. When the probe is not in use, temperature can be set manually using
the  keys.
Assemble the electrode holder and press ON/OFF to turn the instrument on. All LCD
segments will be displayed for a few seconds (or while the ON/OFF is pressed), and then
the instrument will enter normal measurement mode.
After measurement has been taken, switch the meter o, clean the electrode and store it
with a few drops of MA9015 storage solution in the protection cap.
The auto-o feature turns the meter o after 10 minutes of non-use. To disable this feature,
see Setup, Auto O section.
5.3. OPERATION OVERVIEW
MW150 oers simplified pH measurements that are ideal for anyone who requires rapid
and reliable results but works on a tight budget.
It displays 0.01 pH resolution and allows a 3-point buer calibration from the following pH
buers: pH 1.68, 4.01, 6.86, 7.01, 9.18, 10.01 and 12.45.
The bench meter shows calibration status and warning messages that indicate that the
pH electrode requires maintenance.
MEM/MR function can be used to store/recall measured values.
GLP feature provides oset and slope.

GENERAL OPERATIONS 13
MW151 has a wider range of features and can be used in more complex applications
where certain requirements need to be met.
It displays 0.01 or 0.001 pH resolution (set by the user), allows up to 5-point standard
buer calibration and 2 custom buers.
The bench meter shows calibration status and electrode condition warnings (should the
pH electrode require maintenance). It also indicates if the buer solution is contaminated.
The logging feature supports logging up to 1000 records, organized as: manual log-on
demand (max. 200 logs), manual log-on stability (max. 200 logs), interval logging (max.
1000 logs, 100 lots).
MW150 MW151
Calibration up to 3 points up to 5 points, including 2custom
buers
Diagnostics Error messages
GLP
Electrode condition
Error messages
GLP
Log types One memorized reading Manual Log on demand
Manual Log on stability
(Fast, Medium, Accurate)
Interval Logging
Recommended pH
electrodes
MA917B/1 MA917B/1

14 MW150 & MW151 Bench Meters
6. SETUP
Setup mode allows parameters that are not directly related to the measurement to be
viewed and modified.
1. Press SETUP to enter in Setup mode.
2. Use  keys to select required parameter.
3. Press the CAL/EDIT to enter Edit mode.
4. If various options are available, use RANGE/to select desired option.
5. Use  keys to select or change parameter values.
6. Press GLP/ACCEPT to confirm or press CAL/EDIT to exit without changing.
7. Once in Edit mode, below detailed parameters can be set or viewed.
If needed, use ESC to exit Setup mode.
6.1. GENERAL SETUP
pH Information
Use  keys to select whether the pH buer calibration information is enabled or not:
on – enable (default), o – disable.
When enabled, the electrode segment displays the electrode condition (MW151 only).
pHmV
NO MTCATC
USB
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
CUST1
CUST2
DATE
ACCEPT
ºC
ºF
pH
mV
TIME
Calibration Expired Warning
Use  keys to select the number of days since last calibration has elapsed: 1 to 7 days
(default), or o.
pHmV
NO MTCATC
USB
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
CUST1
CUST2
DATE
ACCEPT
ºC
ºF
pH
mV
TIME

SETUP 15
Out of Calibration Range
Use  keys to enable (on – default) or disable (o) out of calibration range warning.
pHmV
NO MTCATC
USB
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
CUST1
CUST2
DATE
ACCEPT
ºC
ºF
pH
mV
TIME
Set Date
Use RANGE/to change editable value (year, month, day) and use  keys to change
the value.
pHmV
NO MTCATC
USB
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
CUST1
CUST2
DATE
ACCEPT
ºC
ºF
pH
mV
TIME
pHmV
NO MTCATC
USB
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
CUST1
CUST2
DATE
ACCEPT
ºC
ºF
pH
mV
TIME
Set Time
Use RANGE/to change editable value (hour, minute or second) and use  keys to
change the value.
pHmV
NO MTCATC
USB
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
CUST1
CUST2
DATE
ACCEPT
ºC
ºF
pH
mV
TIME
pHmV
NO MTCATC
USB
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
CUST1
CUST2
DATE
ACCEPT
ºC
ºF
pH
mV
TIME

16 MW150 & MW151 Bench Meters
Auto O
Use  keys to select desired auto-o time. Available options are 5, 10 (default), 30, 60
minutes and o.
pHmV
NO MTCATC
USB
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
CUST1
CUST2
DATE
ACCEPT
ºC
ºF
pH
mV
TIME
pHmV
NO MTCATC
USB
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
CUST1
CUST2
DATE
ACCEPT
ºC
ºF
pH
mV
TIME
Sound
A short acoustic signal is generated every time a key is pressed. Use  keys to
enable/disable the acoustic signal. Default option is on.
pHmV
NO MTCATC
USB
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
CUST1
CUST2
DATE
ACCEPT
ºC
ºF
pH
mV
TIME
Temperature Unit
Use  keys to select desired temperature unit °C (default) or °F.
pHmV
NO MTCATC
USB
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
CUST1
CUST2
DATE
ACCEPT
ºC
ºF
pH
mV
TIME

SETUP 17
LCD Contrast
Use  keys to set LCD contrast values from 1 to 9 with default value being 9.
pHmV
NO MTCATC
USB
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
CUST1
CUST2
DATE
ACCEPT
ºC
ºF
pH
mV
TIME
Default Values
Use GLP/ACCEPT to return to default values.
pHmV
NO MTCATC
USB
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
CUST1
CUST2
DATE
ACCEPT
ºC
ºF
pH
mV
TIME
Instrument Firmware Version
First LCD line displays instrument firmware version.
pHmV
NO MTCATC
USB
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
CUST1
CUST2
DATE
ACCEPT
ºC
ºF
pH
mV
TIME
Meter ID / Serial Number
Use  keys to assign meter ID (identification number) from 0 to 9999. Use RANGE/
to view meter’s serial number.
pHmV
NO MTCATC
USB
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
CUST1
CUST2
DATE
ACCEPT
ºC
ºF
pH
mV
TIME
pHmV
NO MTCATC
USB
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
CUST1
CUST2
DATE
ACCEPT
ºC
ºF
pH
mV
TIME

18 MW150 & MW151 Bench Meters
6.2. MW151 SPECIFIC SETUP
In addition to General Setup parameters, when operating MW151, the user can set the
following specific parameters:
Log on Meter
Is displayed when a USB cable or USB flash drive is connected. Enter SETUP, select LOG
ON METER, press CAL/EDIT, than use  keys to select EXPORT TO PC. Press GLP/
ACCEPT to confirm or press CAL/EDIT to return to Setup menu.
pHmV
NO MTCATC
USB
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
CUST1
CUST2
DATE
ACCEPT
ºC
ºF
pH
mV
TIME
pHmV
NO MTCATC
USB
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
CUST1
CUST2
DATE
ACCEPT
ºC
ºF
pH
mV
TIME
Log Type
Enter SETUP, select LOG TYPE and press CAL/EDIT to enter Edit mode. Once in Edit mode,
use RANGE/to choose between interval log, manual log and stability log. Use 
keys to set interval time (5 sec – default, 10 sec, 30 sec, 1min, 2 min, 5 min, 15 min, 30 min,
60 min, 120 min, 180 min) and stability type (fast, medium, accurate). Press CAL/EDIT to
return to Setup menu.
pHmV
NO MTCATC
USB
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
CUST1
CUST2
DATE
ACCEPT
ºC
ºF
pH
mV
TIME
pHmV
NO MTCATC
USB
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
CUST1
CUST2
DATE
ACCEPT
ºC
ºF
pH
mV
TIME
pHmV
NO MTCATC
USB
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
CUST1
CUST2
DA
TE
ACCEPT
ºC
ºF
pH
mV
TIME
pHmV
NO MTCATC
USB
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
CUST1
CUST2
DATE
ACCEPT
ºC
ºF
pH
mV
TIME
pHmV
NO MTCATC
USB
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
CUST1
CUST2
DATE
ACCEPT
ºC
ºF
pH
mV
TIME
pHmV
NO MTCATC
USB
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
CUST1
CUST2
DA
TE
ACCEPT
ºC
ºF
pH
mV
TIME
First Custom Buer
Use  keys to set the first custom buer. Use RANGE/to set a default buer value as
starting value. Press GLP/ACCEPT to confirm or press CAL/EDIT to return to Setup menu.

SETUP 19
pHmV
NO MTCATC
USB
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
CUST1
CUST2
DATE
ACCEPT
ºC
ºF
pH
mV
TIME
Second Custom Buer
Use  keys to set the second custom buer. Use RANGE/to set a default buer value
as starting value. Press GLP/ACCEPT to confirm or press CAL/EDIT to return to Setup menu
.
pHmV
NO MTCATC
USB
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
CUST1
CUST2
DATE
ACCEPT
ºC
ºF
pH
mV
TIME
pH Resolution
Use  keys to set the pH resolution (0.01 – default or 0.001). Press GLP/ACCEPT to
confirm or press CAL/EDIT to return to Setup menu.
pHmV
NO MTCATC
USB
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
CUST1
CUST2
DATE
ACCEPT
ºC
ºF
pH
mV
TIME
Separator Type
Use  keys to select the desired character separator (semicolon or comma) to
separate columns in the .csv file. Press GLP/ACCEPT to confirm or press CAL/EDIT to
return to Setup menu.
pHmV
NO MTCATC
USB
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
CUST1
CUST2
DATE
ACCEPT
ºC
ºF
pH
mV
TIME
pHmV
NO MTCATC
USB
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
CUST1
CUST2
DATE
ACCEPT
ºC
ºF
pH
mV
TIME
pHmV
NO MTCATC
USB
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
CUST1
CUST2
DA
TE
ACCEPT
ºC
ºF
pH
mV
TIME

20 MW150 & MW151 Bench Meters
7. pH
7.1 . pH PREPARATION
MW150: Up to 3-point calibration with a choice of seven standard buers.
MW151: Up to 5-point calibration with a choice of 7 standard buers and, additionally,
calibration with custom buers (CUST1 and CUST2).
1. Pour small quantities of the selected buer solutions into clean beakers. Use one
beaker for rinsing and one for calibration.
2. Remove the protective cap and rinse the electrode with the buer solution for the first
calibration point.
For better accuracy, frequent calibration of the pH sensor is recommended. In addition,
the meter must be recalibrated:
ywhenever the pH electrode is replaced
yafter testing aggressive chemicals
ywhen high accuracy is required
ywhen the calibration time out has expired (if the feature is enabled)
yat least once a week
7. 2 . pH CALIBRATION
Custom Buers (MW151 only)
This feature has to be enabled in Setup. Temperature compensation of custom buers is
set to the value of 25°C.
When calibrating with custom buers, the buer value can be modified by pressing
RANGE/. Use the  keys to change the buer value based on the temperature
reading. After 5 seconds, the buer value will be updated.
pHmV
NO MTCATC
USB
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
CUST1
CUST2
DATE
ACCEPT
ºC
ºF
pH
mV
TIME
pHmV
NO MTCATC
USB
OPEN
AUTO
HOLD
SLOPE
CLEAR
CAL
1.68
4.01
6.86
7.01
9.18
10.01
12.45
CUST1
CUST2
DATE
ACCEPT
ºC
ºF
pH
mV
TIME