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163

USA

1-

509-

332-

275

6in

stru

men

ts@

aqu

alab

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ww

w.a

qu

alab

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1451

0 | 1

3-01

-16

Vapor

Sorp

tion

A

naly

zer

Quic

k St

art

Guid

e

VS

A Q

uic

k Sta

rt Gu

ide

• The delete en

try is used to rem

ove an unwanted stage.

 • Follow

 the m

essage on the screen

 to place an em

pty   stain

less steel cup in

 the ch

amber an

d seal it. Press 

to   tare th

e cup.

 • Follow

 the m

essage on the screen

 to place the sam

ple in

  the cu

p and press 

 to weigh

t the sam

ple. • P

ress  to begin

 the test.

5. Running a w

ater activity test— (C

an not be done when

isotherm test is running)

 • R

emove th

e weigh

ing pan

.  • P

ress  until you

 are at the M

easurem

ent Tab (2n

d tab).   Move latch

 left and/or press 

 to start a reading. T

he

  pin

wheel w

ill spin indicatin

g a measu

rement is ru

nning. 

 • T

he a

w  reading for th

e sample an

d the tem

perature w

ill   display w

hen finished. 

 • T

o change betw

een dew

 point an

d capacitive readings,

  you

 will n

eed to toggle the Volatiles Y

es/No option

 in

  the C

onfiguration

 Tab. 

  Volatiles = Y

es g Capacitive Sen

sor   Volatiles = N

o g Dew Poin

t Sensor

Note: A

ccuracy ch

anges to +/- 0.02 w

hen

volatiles “Yes”

is selected

.

VS

A Q

uic

k Sta

rt Gu

ide

1. Getting Started—

 • P

lace the A

quaLab V

SA on a fl

at surface. U

se the bu

bble          level(Figu

re 1: Adjustm

ent an

d bubble level) an

d use th

e   adju

stable feet to level the in

strument. T

he sm

all rubber 

  feet on

 the back

 of the low

er plate are to prevent tip-over

  and do n

ot need to be tou

ching th

e table. • U

se the A

quaLab V

SA where en

vironmental tem

perature 

       and humidity rem

ain fairly stable.

Figure 1: A

dju

stmen

t and

bu

bb

le level.

 • T

he A

quaLab V

SA needs to be on

 a stable platform and 

  evalu

ated to verify shippin

g did not dam

age the scale

  perform

ance. T

o test scale stability:    1. T

urn on the V

SA and allow

 instru

ment to w

arm 

     u

p for 2 hours.

   2. N

avigate to the D

iagnostics screen

 in the

     Configuration

 menu and press 

.   3. Scroll dow

n to th

e screen that sh

ows th

e weigh

t.       Readin

gs should vary n

o more th

an 0.5 m

g.

Adjustm

ent feet: 

Two on

 front an

d one

on the m

iddle back.

Bu

bble Level

Lower B

lock

VS

A Q

uic

k S

tart

Gu

ide

    the up and down arrows. Choosse any value between 

 0.003 and 1.0 

a w. The step setting for DVS determines  

th

e a w values for equilibration and consequently the 

 resolution. If starting 

a w is 0.1 and has a step setting of 

 0.10 aw results in humidity being controlled to 0.1, 0.2, 

 0.3 … up to the final aw, remaining at each level until 

 either equilibrium is achieved based on the trigger value 

 or it reaches the timeout value. Setting a higher 

 value makes the test faster, but decreases the quantity 

 of equilibtation points.

• To choose the trigger %dm

/dt value that indicates

 equilibration, press enter with “Trigger” highlighted

 and then cycle to the desired value using the up and

 down arrows. The trigger can be shut off or be any

 value between 0.001-1%/hr. Choose the number of

 

events required to meet the trigger value. The trigger

 value represents an acceptable change in mass per

 change in time to indicate equilibrium for a given step. 

 Setting a higher value will make the test faster, but

 may not result in com

plete equilibrium. If the trigger

 is turned off, the sample will be held at each step for

 the time indicated by the timeout setting.

• To choose to include a timeout setting, press  with

    “Timeout” highlighted and then cycle to the desired

 value using the up and down arrows. You can select any 

 value between 5.0 min to 30 days. The timeout 

 determines the maximum time allotted for each aw step 

 NOT the time from

 starting 

a w to final aw. The default 

 value is off, which means there is no timeout value 

 and only the trigger value determines the end of step. 

 If you set both a trigger value and timeout value, 

 whichever VSA reaches first determines the end of step.

• To choose to have the isotherm loop, press  with

   “Loop” highlighted to toggle between on and off. 

   Turning loop on causes the isotherm to automatically

   return to the start 

a w (with the same settings) once

   the final aw has been achieved. This would create

   both an adsorption and desorption curve (or vice versa

   depending on the starting direction). 

VS

A Q

uic

k S

tart

Gu

ide

   4. Lightly tap the table with one finger. If the readings

      vary more than 0.5 mg after tapping, the table is 

      probably too unstable for accurate weight readings 

      during a test and will need to be made more rigid 

      or another location found for this equipment. 

                 Contact your AquaLab distributor if the scale 

      readings are unstable after placing the unit on a  

      stable structure.

Figu

re 2

: Des

icca

nt

inst

alla

tion

   • Desiccant tubes are installed by orienting the tube so that

    the black colored valve inserts into the black receiving hole

    as shown in Figure 2. Before insertion make sure that the 

      desiccant tube lid is firmly sealed onto the desiccant tube. 

      (See Manual for instructions) Lift the tube into the area 

      above the desiccant receiver and then insert the tube into 

      the mating holes while shaking the tube slightly. Once in 

      place, the desiccant tube is sealed for flow purposes and 

      may move side to side if contacted.

Desiccant Cartridge

Desiccant Receiver

Black Valve

Black Receiving Hole

VS

A Q

uic

k Sta

rt Gu

ide

• To ch

oose to include a tim

eout settin

g, press  with

   “Timeou

t” highligh

ted, and th

en cycle to th

e desired    valu

e using th

e up an

d down arrow

s. Any valu

e between

            5.0 m

in to 30 days can

 be selected. The tim

eout 

           determines th

e maxim

um tim

e allotted to move from

            th

e starting a

w  to the final a

w  (DDI on

ly) and is option

al.             T

he defau

lt value is off, w

hich mean

s there is n

o            tim

eout valu

e.

• T

o choose to h

ave the isoth

erm loop, press 

 with

   “Loop” h

ighligh

ted to toggle between

 on and off. 

   Turning loop on

 causes th

e isotherm

 to autom

atically    retu

rn to th

e start aw  (w

ith the sam

e settings) on

ce    the final a

w  has been

 achieved. T

his w

ould create both

            an

 adsorption and desorption

 curve (or vice versa 

           dependin

g on the startin

g direction).

• For D

VS m

ethod

• T

o choose th

e starting a

w , press  with “Start”

   highligh

ted, and th

en cycle to th

e desired value using

   the up an

d down arrow

s. Any valu

e between

 0.03    and 0.95 a

w  can be ch

osen includin

g “curren

t”.     Choosin

g “curren

t” mean

s that th

e stage will start at

th

e initial a

w  of the sam

ple. Press 

 when finished.

• To ch

oose the final a

w , press  with “Fin

al”    highligh

ted, and th

en cycle to th

e desired value using

   the up an

d down arrow

s. Any valu

e between

 0.03    and 0.95 a

w  can be ch

osen includin

g curren

t     (see“cu

rrent” defi

nition

 above). Selecting a fi

nal a

w    that is low

er than the startin

g aw  w

ill result in

   desorption

, while selectin

g a final a

w  higher th

an the

   startin

g aw  w

ill result in

 adsorption. Press 

 when

   finished.

• To ch

oose the tem

perature of th

e stage, press  with

   “Temperatu

re” highligh

ted, and th

en cycle to th

e    desired tem

perature u

sing th

e up an

d down arrow

   keys. A

ny tem

perature betw

een 15-60°C

 can be

   chosen

. Each

 stage can run at a u

niqu

e temperatu

re.

• T

o choose th

e desired aw  step, press 

 with “Step”

   highligh

ted and th

en cycle to th

e desired value using

VS

A Q

uic

k Sta

rt Gu

ide

Figure 3: Tan

k fi

ll extension

 • R

emove th

e black plu

g on the clear plastic tan

k fill

  exten

sion located on

 the back

 right of th

e VSA. 

  (Figu

re 3). Fill the tan

k with deion

ized water u

ntil fu

ll.        Fin

ger tighten

 the w

ater fill plu

g once fi

nished.

 • T

o remove th

e water from

 the w

ater tank, th

e water tan

k

  drain

 plug is u

sed. • Figu

re 3 shows th

e location of a fi

lter that w

ill need to be

  rem

oved from tim

e to time w

hen dust bu

ilds up on

 it. The

  housing arou

nd th

e filter is a sn

ap on housing th

at is easily   rem

oved. 

Water Fill P

lug

Water T

ank Fill E

xtension

Upper H

orizontal D

rilled Hole

Water T

ank Drain

 Plug

Fan Filter

VS

A Q

uic

k S

tart

Gu

ide

•

For

DD

I m

etho

d

• To choose the starting a w, press  with “Start”

   highlighted and then cycle to the desired value using

   the up and down arrows. Any value between 0.03 and 

           0.95 a w can be chosen including “current”.  Choosing 

           “current” means that the stage will start at the initial a w

           of the sample. Press  when finished.

  • To choose the final aw, press  with “Final” highlighted 

           and then cycle to the desired value using the up and 

           down arrows. Any value between 0.03 and 0.95 aw c

an

           be chosen including current (see “current” definition 

           above). Selecting a final aw that is lower than the 

           starting a w will result in desorption, while selecting a 

           final aw higher than the starting a w results in adsorption. 

           Press  when finished.

• To choose the temperature of the stage, press  with

   “Temperature” highlighted and then cycle to the

   desired temperature using the up and down arrow keys

   (hold down arrows for accelerated scrolling). You may 

           choose any temperature between 15 and 60 °C, 25 °C is 

           default. Each stage can run at a unique temperature.

• To choose the desired 

a w resolution, highlight 

           “Resolution” press 

 with “Resolution” highlighted and 

           then cycle to the desired value using the up and down 

           arrows. You may choose any value between 0.003 

           and 1.0 

a w. The resolution for DDI determines the target 

a

w resolution. Setting a higher resolution value makes 

           the test faster, but decreases the 

a w resolution. W

e            recom

mend a DDI resolution of 0.01 aw.  

• To choose the air flow rate, press  with “Flow”

   highlighted, and then cycle to the desired value using

   the up and down arrows. Any value between 

   10-163 ml/min can be selected. Higher flow rates will

   speed up the test, but may result in lower data

   resolution and non-equilibrium conditions. The

   default value of 100 ml/min is suitable for most

   products.

VS

A Q

uic

k S

tart

Gu

ide

Figu

re 4

: Sam

ple

cup

and

low

er b

lock

ass

emb

ly

   • Figure 4: assembly illustrates the proper positioning of the 

       parts in the lower block. The air cylinder is placed into 

       the bore of the base block. It should slide into the block 

       easily and settle at the bottom

 of the bore. The weigh 

       pan connects to the scale and holds the sample cup. For 

       best results, verify cleanliness of all parts.

2. A

quaL

ab V

SA P

erfo

rman

ce V

erifi

cati

on o

verv

iew

—

 • AquaLab VSA performance and cleanliness should be

  checked frequently; before each isotherm test is 

  recommended.

 • Press  until you are at the Measurement Tab.

 • Use AquaLab Verification Standards to verify performance

  or adjust linear offset.

Sam

ple

Cup

Lid

Only used for sample storage and 

must be removed during tests.

Sam

ple

Cup

Stainless steel cups are

recommended. Plastic cups

absorb moisture over time.

Wei

ghin

g P

an

Air Cylinder

Base Block Bore

VS

A Q

uic

k Sta

rt Gu

ide

 • E

nsure sam

ple temperatu

re is within 4 °C

 of chamber 

       temperatu

re.

4. Starting a Test—

 • B

efore starting a test, set th

e Volatiles: Y

es/No option

 in

  the con

figuration

 menu. If you

r sample h

as volatiles,   select “Y

es” otherw

ise select “No”.

 • O

n the m

ain screen

, select the test w

izard .

 • Follow

ing several w

arnings, begin

 configuring th

e test by        providin

g a name for th

e test using th

e arrow keys 

       and th

en press 

. (The name of a previou

s test will appear 

       by default.)

 • E

nter in

itial moistu

re conten

t if known (option

al). Press 

  to con

tinue or 

 to go back.

 • Setu

p each stage of th

e isotherm

 test. A stage is u

sed to   adju

st the isoth

erm settin

gs for an individu

al sample (u

p to   20 stages). E

ach stage is setu

p with the isoth

erm meth

od    (DDI or D

VS) an

d the settin

gs for that portion

 of the

  isoth

erm. Once a stage is created, it can

 be modifi

ed or   deleted an

ytime before th

e test is started. 

i.e. For m

ilk pow

der, Stage 1 cou

ld u

se the D

DI m

ethod

to

ram

p qu

ickly from

0.1 to 0.4 aw an

d Stage 2 cou

ld u

se

th

e DV

S meth

od to step from

0.4 to 0.8 aw slow

ly in

0.05 aw in

cremen

ts.

 • T

o setup a n

ew stage, select “n

ew” an

d press . A screen

  with several param

eters will appear. If a previou

s test   has been

 run, th

e stages for that test w

ill be listed by   defau

lt. These stages can

 be used as-is or u

pdated with

  new settin

gs. If you need to delete a stage, go to th

e   specifi

c stage and press 

. Scroll down to th

e bottom of

  the stage settin

gs select “Delete” an

d press .

 • Select th

e isotherm

 meth

od as either D

ynamic D

ewpoin

t   Isoth

erm (DDI) or D

ynamic V

apor Sorption (DVS). D

DI

  will create a dyn

amic isoth

erm and D

VS w

ill create a   static or equ

ilibrium isoth

erm. The oth

er choices w

ill   adju

st based on which meth

od is selected. 

VS

A Q

uic

k Sta

rt Gu

ide

 • T

o verify, remove w

eigh pan

 and th

en place sam

ple cup

  con

taining on

e of AquaLab’s verifi

cation stan

dards in

  sam

ple chamber. C

lose lid and carefu

lly avoid spillage; See   Figu

re 5. • M

ove latch left or press 

 to start a reading. T

he

  pin

wheel spin

s to indicate a m

easurem

ent is ru

nning.

  The a

w  reading for th

e standard an

d the tem

perature

  displays w

hen finished. M

ake su

re the a

w  reading

  on the stan

dard is within +/-0.005 of th

e correct aw  for th

e   stan

dard. (+/- 0.02 if cap sensor is u

sed) • If an

 offset adjustm

ent is n

eeded, refer to chapter 7 in

 the

  user’s m

anual.      

Figure 5: Sam

ple chamber

3. Sample Preparation—

 • Fill sam

ple cup no m

ore than half fu

ll (~7ml). 

Do N

ot Overfill!

 • Sam

ple size can be betw

een 500 an

d 2,000 mg.  W

e        recom

mend 1000 m

g. • E

nsure th

e rim and ou

tside of sample cu

p are clean.

Lid

Base