8
equilibrate, and press CALIBRATE (screen
14). A successful calibration will bring up
screen 15. Repeat the procedure for the
rest of your calibration standards.
NOTE: The calibration standards must be
sequential.
Inotherwords,theindexofwateris<std#1
<std#2<std#3<std#4. TheAR6 will not sort
the standards if you scramble their order,
and the accuracy of your readings will
diminish.
5.1PreparingthePrismSurfaceforSamples
Becausearefractometerisanopticalinstrument,itis
criticaltothoroughlycleanthesamplemeasurementarea.
Any residue could result in erroneous
readings or error messages.
Clean the prism surface and sample well
with diluted soapy water or alcohol followed
by a distilled water rinse before applying a
sample. Wipe clean with a soft cloth.
5.2 Applying the Sample, Taking
Readings, and Shadowline Dis-
play
Placethesampleontheprismsurfaceusingapipetor
applicator.Makesuretheentireprismsurfaceiscovered
(Figure 4). Optimum readings are obtained
if enough sample is placed in the well to
cover a millimeter or two of the walls of the
sample well.
ClosethecoverandpresstheREADkey.The
REICHERT AR6 will display the reading in
the selected mode.
Ifyouchangemodesbeforetakinganewreading,the
instrumentwillusedatafromthecurrentreadingto
produceanewdisplayinthenewlyselectedmode.
Forexample,ifyouwantareadinginnD,fol-lowedby%
Solidsusingonemeasurementofthesample,operate
the REICHERTAR6 in the nDmode. Then
press the MODE key until % Solids or %
Solids-TC registers on the display. A %
Solids reading will automatically be
displayed. If the READ key is pressed, the
AR6 will take an entirely new measure-
ment.
Inaddition,theinstrumentnowhastheabilityto
graphicallydisplaytheshadowlineviatheLinearScanned
Arrayoutput.Thisallowstheuserto“seewhatthe
refractometersees”.Thisfeaturemaybeoperatedafter
anyreadingbypressingthe“CALIBRATE”and“MODE”
keyssimultaneously.Therefractometerwillthengenerate
anddisplayagraphoftheLinearScannedArrayOutput.
See example below.
Two lines will appear. The rainbow shaped
line is the Reference Scan. The line which
begins near the bottom of the screen and
moves upward to intersect the Reference
Scan is the Sample Reference Scan. Also
shown will be the “CCN”. This is the
Crossing Cell Number which is the exact
cell on the array which the edge of the
shadowline falls on. At this point, a box will
be displayed. This box may be repositioned
anywhere on the screen. Pressing “SET
UP” will zoom in on this boxed area.
Pressing “SET UP” again will return to the
full graph view. The X and Y values are also
displayed. These are simply the location of
the box on the screen. The line for the
reference scan may be toggled on and off
by pressing “READ” and “INITIATE”
simultaneously in the full graph display. To
exit the shadowline display, press “CALI-
BRATE” and “MODE” simultaneously.
6.0DIAGNOSTICS
Thefollowingscreensdescribepotentialerrorsthatcan
occurwhenoperatingtheAR60O:
“HighSample”screen-Thesamplehasarefractive
indexexceedingthe1.52000operatingrangelimit(see
Screen 16).
“Low Sample” screen - The sample has a
refractive index below the 1.32000
operating range limit (see Screen 18).
“WaterCalibration”screen-Thisscreenwillbedisplayed
whentheREADkeyispressedbeforeawater
calibration.Cleantheprism,calibratewithwaterand
rereadthesample(seeScreen19).
“LampisnotAligned”screen-Thisscreenmayappearif
asamplehasbeenleftontheprism.Thoroughlyclean
anddrytheprismsurface.Ifthemessagepersists,the
lampmayneedre-alignment.Notethedirectiontomove
thelampandre-centerthelamp.Alignmentisdonewith
theinstrumentrunning.Useametalscrewdrivertomove
thelampduetoit’shightemperature.Exercisecareto
avoidbreakingthelamp.Weareyeprotectionincasethe
lampshatters.Followtheonscreeninstructiontoinitiate
and recalibrate the AR6 (see Screen 20).
“ReplaceLamp”screen-ThelampisburnedoutReplace
the lamp following instructions in section
11.0 LAMP REPLACEMENT (see screen
21).
“CouldNotTakeProperReading”screen-Thisscreen
willbedisplayedifthelampintensityhaschangedsince
theinitializationprocedure.Thiscanbecausedbynormal
agingofthelamporlargelinevoltagefluctuations.Check
tobesurethelampisilluminated,turntheAR60Ooff
andbackon,followtheonscreeninstructiontoinitiate
andcalibrateinstrument(seeScreen22).Ifthecondition
persists change the lamp. If it continues
with a new lamp a line voltage conditioner
may be required.Alternately, theAR60O
could be plugged into a separate line
source, preferably a source without
electrical appliances which have large
current draws (e.g.: motors, compressors,
heaters, etc.).
7.0 CHANNELS
Channel one (1) on the REICHERT AR6 is
pre-programmed at the factory with the %
Sucrose or «Brix» scale per the
International Commission for Uniform
Methods of SugarAnalysis (ICUMSA).
Upto14additionalcustomchannelsmaybe
programmedusingyourownrefractiveindex/
temperature/%Solidsdata.Accesstothechannelsis
fromtheSETUPscreen.Customchannelsmayalso
includedefinitionsforunitsofmeasuresuchasspecific
gravity,%protein,g/ml,etc.Theunitofmeasurelabels
arecompletelydefinableandupto20characterscanbe
used.Resultsmaybedisplayedinasmanydecimal
placesasdesired.
Tolearnmoreaboutcustomchannelprogamming,
request«CustomChannelGenerationfortheAutomatic
RefractometerLine»fromaReichertrepresentative.Be
suretoinformtherepresentativethatyouareusing
softwareversion12.6.
8.0 AUTOMATICTEMPERATURE
COMPENSATION
AutomaticTemperatureCompensationcorrectsreadings
taken over a range of temperatures (e.g.:
10°C – 40°C in channel 1) to a reference
temperature reading (usually 20°C). This
can be used in lieu of controlling the
temperature of the prism and sample with
an external water bath. Temperature
correction or control is necessary because
refractive index varies inversely with
temperature. A typical temperature
coefficient for an aqueous solution is -
0.00021°C. For an organic liquid it is
typically -0.0004/°C.
However,itisalwaysnecessarytoallowyoursample
temperature to equilibrate so that the AR6
can properly correct for temperature.
Theautomatictemperaturecompensationmodesin
channel1arebasedonthetemperaturecoefficients
(nD1°C)ofsucrosepertheICUMSAscales.Whentaking
readingsinthenD–TC(refractiveindex–Temperature
Compensated) mode these coefficients
may not be valid depending on the solution.
