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17

PAWKIT

4.1.2  VERIFY CALIBRATION

Use the following steps to verify the PAWKIT calibration.

NOTE:  An error code of 9.99 at any time during the process indicates that the sensor has failed and that the 
instrument needs to be serviced. Refer to 

Section 4.4

 for shipping instructions.

1.  Using a vial of the 0.760 

a

w

 NaCl standard, empty the entire contents of the vial into a 

sample cup.

2.  Place the PAWKIT over the sample cup as described in the 

Section 2.1.2

.

3.  Press the 

I button to take a reading.

If it is reading the correct water activity (±0.02), the PAWKIT needs no adjustment for this 
standard. Skip t

step 7

.

If the first reading was not the correct water activity (±0.02), clean the PAWKIT according 
to the instructions in 

Section 4.2

 and take a second reading.

If the second reading is the correct water activity (±0.02), the PAWKIT needs no 
adjustment at this time. Skip t

step 7

. If the second reading is not correct, continue to 

the next step.

4.  Press the 

II button (on the right) once to get the Calibration Mode screen (

Figure 13

).

Once the reading is finished, the 

II button (on the right) activates. The II button is only 

active until the PAWKIT shuts itself off.

Figure 13  Calibration Mode screen

Figure 13

 shows that the PAWKIT is ready to have its calibration adjusted up for the 

0.76 standard. The number in the upper right corner indicates the water activity 
measurement that the PAWKIT just read. Press the 

II button to scroll through the other 

selections. They are: 

u76

d76

u25

d25

Sto

u92

, and 

d92

. The 

u

 and 

d

 before each 

number stand for 

up or down adjustment for each standard. The numbers (25, 76, and 

92) correspond to the water activity of a verification standard (0.76, 0.25, and 0.92 

a

w

). 

The 

Sto

 position stores a reading.

EXAMPLE:

If the NaCl reading is lower than it should be, press the 

II button to scroll to 

u76

 (adjust up for 0.76 standard). If the reading is higher than it should be, scroll to 

d76

 (adjust down for 0.76 standard).

NOTE:  Scroll feature is continuous, so if desired adjustment screen is passed, keep pressing the II button 
until cycled back to the correct screen.

Содержание AQUALAB PAWKIT

Страница 1: ...PAWKIT...

Страница 2: ...3 3 Theory 11 3 3 1 Moisture Content 11 3 3 2 Water Activity 12 3 3 3 Water Potential 15 3 3 4 Sorption Isotherms 15 4 Service 16 4 1 Verification and Calibration 16 4 1 1 Verification Standards 16 4...

Страница 3: ...ii 4 5 Customer Support 26 4 6 Terms and Conditions 27 References 28 Index 29...

Страница 4: ......

Страница 5: ...preparing samples and maintaining and caring for the PAWKIT Please read these instructions before operating the PAWKIT to ensure that the instrument performs to its full potential Verify that all PAWK...

Страница 6: ...pling a beep signals when it is finished to avoid damage to the sensor If a sample is accidentally left in the chamber for an extended period of time be sure to check the calibration when the instrume...

Страница 7: ...ned to cover the bottom A larger sample surface area increases instrument efficiency by shortening the time needed to reach vapor equilibrium However if the sample cup is too full contamination of the...

Страница 8: ...reached ambient temperature before attempting to read again If the sample is colder than the ambient temperature of the PAWKIT the accuracy of the reading after 5 min may be questionable Wait until t...

Страница 9: ...recess in the bottom of the PAWKIT Figure 4 PAWKIT placement on sample cup A correctly positioned cup results in the PAWKIT being level on the bench when sitting on the cup and the sensor cover legs...

Страница 10: ...E Pressing the I button any time during a measurement restarts the water activity measurement Once the measurement process has been started the PAWKIT begins to display water activity measurements as...

Страница 11: ...rement Figure 7 DO NOT lift or move instrument during measurement 6 After 5 min the instrument displays the final water activity and beeps 5 times The sunburst disappears when the water activity readi...

Страница 12: ...nd and rotate until it snaps into the closed position covering the sensors Snap cover tab in place Figure 9 Closing the PAWKIT To turn off the PAWKIT leave it idle for more than 5 min and it will shut...

Страница 13: ...nge 0 00 1 00 aw Resolution 0 01 Accuracy 0 02 Sample Temperature Resolution 0 1 C Accuracy 0 2 C Read Time 5 min PHYSICAL SPECIFICATIONS Dimensions Length 10 7 cm 4 21in Width 6 6 cm 2 60 in Height 2...

Страница 14: ...umidity noncondensing Power 2 3 V 16 mm coin cell batteries life of approximately 3 years COMPLIANCE Manufactured under ISO 9001 2015 EM ISO IEC 17050 2010 CE Mark 3 2 PAWKIT COMPONENTS Figure 10 show...

Страница 15: ...DL Water Activity Meter Contact Customer Support for more details The PAWKIT system comes with 60 disposable plastic sample cups and one stainless steel sample cup Additional quantities of cups can be...

Страница 16: ...of microorganisms lipids and enzymes relate to water activity While other factors such as nutrient availability and temperature can affect the relationships water activity is the best single measure...

Страница 17: ...ple and the PAWKIT temperature For water activity measurements to be accurate to 0 02 temperature difference measurements need to be accurate to 0 02 C The PAWKIT infrared thermometer measures the tem...

Страница 18: ...sufficient pressure is applied to the solute water mixture to just stop the ow this pressure is a measure of the osmotic potential of the solution Addition of 1 mol of an ideal solute to 1 kg of wate...

Страница 19: ...t both the osmotic and matrix binding of water in a product Therefore a relationship exists between the water activity and moisture content This relationship is called the sorption isotherm and is uni...

Страница 20: ...ETER The verification standards have been produced under a strict quality assurance regime and their accuracy is veri ed by an independent third party instrument They are very accurate easy to use and...

Страница 21: ...step 4 Press the II button on the right once to get the Calibration Mode screen Figure 13 Once the reading is finished the II button on the right activates The II button is only active until the PAWKI...

Страница 22: ...the standard that is closest to the water activity range of the sample material being tested In other words if it is normally higher than 0 76 aw use the 0 92 standard If it is normally lower than 0 7...

Страница 23: ...rned to METER for maintenance in the following areas system inspection parts replacement and instrument cleaning Replacement parts can also be ordered from METER Contact Customer Support for more info...

Страница 24: ...st of the outer case 3 Begin each step cleaning the chamber and the thermopile sensor using a new KIMWIPES strip wrapped around the plastic swab included in the cleaning kit If sample material is spil...

Страница 25: ...e edge of the filter Figure 16 2 The PAWKIT shipped with three spare filters and additional filters can be ordered by contacting Customer Support 3 Be careful of the capacitance humidity sensor Figure...

Страница 26: ...ity sensor 4 2 3 BATTERY REPLACEMENT The PAWKIT uses two lithium ion battery cells that should last for several years If the battery charge is low a low battery indicator icon Figure 18 will persisten...

Страница 27: ...battery 1 Remove the PAWKIT bottom by unscrewing the two screws Screw locations M ADE IN THE USA M ETER Group Inc USA Pullm an WA PAWKIT PW K00009000 Figure 19 Battery compartment screws 2 Separate t...

Страница 28: ...batteries so positive contact is facing down into the elastomer pocket Make sure the two small springs Figure 21 which make contact between the battery terminal and the circuit board are in place Lith...

Страница 29: ...the packaging 3 If the original packaging is not available pack the box moderately tight with packing material e g Styrofoam peanuts or bubble wrap ensuring the instrument is suspended in the packing...

Страница 30: ...TH AMERICA Customer service representatives are available for questions problems or feedback Monday through Friday 7 am 5 pm Pacific time Email support food metergroup com sales food metergroup com Ph...

Страница 31: ...PAWKIT 4 6 TERMS AND CONDITIONS By using METER instruments and documentation you agree to abide by the METER Group Inc USA Terms and Conditions Please refer to metergroup com terms conditions for deta...

Страница 32: ...8 REFERENCES REFERENCE Labuza Ted P K Acott S R TatiNl R Y Lee Jv Flink and W McCall Water activity determination a collaborative study of different methods Journal of Food Science 41 no 4 1976 910 91...

Страница 33: ...e chamber lid See sample chamber lid close cold sample See temperature compliance 10 CE 10 cosmetics See theory customer support 26 D d25 See calibration standards d76 See calibration standards d92 Se...

Страница 34: ...hamber lid open P PAWKIT accessories 1 features 10 hardware 11 OFF 8 ON 6 operation 2 8 precautions capacitance humidity sensor 22 23 sampling 2 preparation for operation 2 samples 3 pressure effect S...

Страница 35: ...y 15 homogenous 3 humidity 11 12 lipids 12 liquid phase water 12 loss on drying 11 microbial growth 12 multicomponent food 13 osmotic effects 14 perishability 11 pharmaceuticals 11 quantitative analys...

Страница 36: ...F 1 509 332 5158 E info metergroup com W metergroup com METER Group AG Mettlacher Stra e 8 81379 M nchen T 49 89 12665236 F 49 89 12665220 E info metergroup de W metergroup de KIMWIPES is a registere...

Страница 37: ......

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