General Tools FHT User Manual

Fr ui t Ha rdness Tes te r

In st ru ct io n Ma nu al

FRUITS & V EGE TABLES
MULTIPL E DISPLAY UN IT-KG, LB, N & P a
EASY ZER O ADJUST MEN T.
ACCURA CY VE RIFICATI ON

ALL RI GHTS RE SERVE D

Gener al op eration preca uti ons

WARNING

Accur ate F ruit Testing Require s:

Contr oll ing tip penetra tion.
Provi din g a mean s to ve rif y
gage ac cur acy.
Contr ollin g th e speed of tip
penet rat ion.

!

1. FEATU RES

The Ripeness Tester is a hand-

*

held compa ct penetromet er for
f r uit fi r m n es s a n d s o me
vegetabl e hardness testing, the
universally accepte d measure
of ripeness.

* The FH T series is the growers'

indispensable tool for knowing
when to pick and ship.

* The FHT Fruit Tester measures

the f orc e re q uir e d to pus h a

plunger tip of spec ified size
into the f ruit pulp. The force
reading as sists in determ ining
the appropr iate p icking time or
moni t orin g frui t soft e nin g
during storage.

* Becau se of the num ber of fruit

a n d v eg e t ab l e v a r i e t i es ,
geo gra p hi c al l oca tio n s a n d
o t h e r v a r i a t i o n s , t h e
a p p rop r i a te f i rmn e s s f or
harvesting will vary. There fore
F H T u s e r s m u s t c o m b i n e
ex pe ri en ce and expertise t o
es tabli sh the firmne ss value
that applies to th eir sp ecific
variety an d locale.

* Automatic power off to conserve

power.

* Can communicate with PC for

r e c o r d i n g , p r i n t i n g a n d
a n a l y z i n g b y t h e o p t i o n a l
software and cable for RS232C
interfac e.

2. A GU IDE TO SELE CT THE
MODEL

the model of FHT Fruit Testers
to cho se from 3 models is used
with spe cific size penetrometer
tip s for tes tin g rip ene ss o f
specific fruit.

FHT-801

(3.5mm) Small Fruits, Soft Fruits,

FHT-802

( 3.5mm ) S ma ll & L a r ge

Fruits, Firm Fruit s,
Hard Fruits

FHT-803

(7.9mm) Larger Fruits, Firm

Fruits ,Hard Fruits

(11.1mm) Apple, Firm Fru its

Small Fr uits: e.g. Stra wberry,

Cherry, Grape ,
Berries

Soft Fruits: e.g. Peach, Banana,

A p r i c o t, P l u m,
M e l o n , C i t r u s ,

Persimmon
Firm Fruits: e.g. Pear, Nectarine, Kiwi
Hard Fruits: e.g. Avoc ado

3. SPECIFICATIONS

Display 4 digits,10 mm LCD

Range:

Model FHT-801

0.2-5.0 kgf/cm

2

Tip s ize 3.5mm
Model FHT-802

0.5-15.0 kgf/cm

2

Tip s ize 3.5mm
Model FHT-803

0.2-11.0 kgf/cm Tip size 11.1mm

0.4-22.0 kgf/cm Tip size 7.9mm

2

2

Tip size ca n be intercha nged
after tip si ze is chosen.

Resolution:

0.01 if reading<10

0.1 if 10<reading<99.9
1 if reading >100

Unit conversion:

kgf (kgf/cm )

lbf (lbf/cm )
N (N/cm )

2

2

2

Pa

Accuracy: ± (1%H+0.1)kg f/cm

Power supply: 4x1.5 AAA size

2

Th an k yo u for you r sele ct ion of
th is Fr uit Hardne ss Test er. To
en su re th at you g et th e most
ou t of th e in st rument, we
st ro ngly r ecommen d you r ead
an d fo ll ow th e i nstruct io ns in
th is m an ua l ca refully.

Power off : 2 modes

Manual off at any t ime
A u t o p o w e r o f f a f t e r 5
m in u t e s f r om l a s t k e y
operation

Operating conditions:

Temperature : 0- 45℃
Humidity : below 90% RH

Dimensions:

204x62x33mm or

8.0x2.4x1.3 inch

Weig ht:

230g (not including batteries)
Standard accessories included :
Carrying case ………………1 pc.
Operation manual………… .1 pc.
Optional accessory:

Cable and software for

RS232C and USB

4. FRONT PANEL DESCRIPTIONS

3-1

3-8

3-5

3-6

3-7

3-1 Display
3-2 Power key ( Mul tif unctional)
3-3 Unit conv ers ion
3-4 Tip select ion ( FHT- 803 only)
3-5 Max hold ke y
3-6 Zero
3-7 Plunger t ip
3-8 RS-232C i nte rfa ce
3-9 Battery c omp art ment

3-9

3-2
3-3

3-4

5. MEASUREMENT PROCED URES

Larger Fruits

A. Sele ct an approp riate plunger tip

for the commo dity to be tes ted.
See “A G UID E TO SELEC T
TH E MOD EL”.

B. Select a random sample of 10 to 15

fruits of uniform size and the same
temperature or 3% of the lot to be
sampled. For best results, suggest
one person should test the lot.

C. Rem ov e a disc o f s kin on

opposite c he ek s of the fruit
midway b etween the stem and
bottom on sun and shade sides.
Then proceed with pun cture test.

D. Zero adjustment

Hold t he FHT verticall y with the
plunger tip hanging in the ai r, the

reading on the display should be 0.
If not, depress the 'ZERO' key to
make the FHT tester display '0'.

E. Hold th e fruit against a har d

s u r f a ce a n d f or c e t h e t i p
ve rticall y i nto the p ulp at a
un iform speed ( take abou t 3
seconds).

F. T he tip sh oul d c onsis te ntly

penet rate to th e break in tip
diameter or to the scribed line on

some tips.
G. Record reading on the disp lay.
H. If a maximu m reading is need ed,

just press the key 'MAX' till t he

mark 'Max' shows on the display

before taking measureme nts.

The appear ance of mark 'Max ' is

controlled by the key 'MAX' .
I. To take the next measurement, just

depress the 'ZERO' key and repeat
steps from E to G.

J. Unit conversion is contr olled by

depressing the key 'UNIT' .
K. For the model FHT-803, make sure

th e plun ger ti p is in a ccordance

with th e tip siz e on the display. If
not, pres s the key '7.9 /11.1' to
choose.

Smaller Fruits

Similar to large fruit testing except:

A. Make a p uncture test o n only

one cheek midwa y between
the stem and t he bottom.

B. R e mov a l of the s kin i s

unnecessary.

C . P en e t r at i o n s h o u l d b e

suf f ici e nt t o obta i n pea k
reading. Repet itive testi ng is
a perfect testing techniq ue for
small fruits.

6. BATTE RY REPLA CEMEN T

A. When the batte ry symbol

appears on the display, it is
time to repl ace the batteri es.

B. Slide the Battery Cover aw ay

from the tes ter and remove th e
batterie s.

C. Install batteries payi ng

careful at tention to pola rity.

7. MAINTENANCE

A. Before daily use, exerci se th e

pl unger in and o ut for 1 0
s e c o n d s t o e n s u r e t h e
mechanis m functions fre ely.

B. A fter da ily use, cl ean the

penetrometer ti ps. C arefully
hold th e tester with the loa d
shaft po inting down under a
slowly flowi ng w ater faucet
for a few seconds, dry with a
towel and allo w to dry fur ther
by s tan din g i t wit h sha ft
pointing down.

C. Th e FHT tester shoul d nev er

be lubricat ed w ith oil since
thi s w ill acc umu l ate dus t
causing increa sed fr iction and
decreased accuracy.

WARNING

!

PART 8 AND 9 ARE ONLY FOR
SKILLED AND PROFESSIONAL
PERSONNEL ONLY.

Users are not suggested to try
to c arry out the operations in
part 8 a nd p art 9 . Improper
operation will lead to the FHT
tester i naccu rate, ev en could
not work.

8.HOW TO SET THE TIME OF
AUTO PO WER OFF

The default sett ing for auto po wer
off at th e f actory is 5 mi nutes.
That means the tester will auto
power off 5 min utes from the t ime
of last key operat ion. Users can
change it to any val ue between 0­9 m inute s by fo llowing step s.
Depress the PO WER for ab out 4
seconds, release it after "OFF"
shows on di splay, then press the
key 'MAX' to preset the time as
desired. To disable the fun ction of

auto power off, just preset the
time to 0. the tester will only be
shut down ma nually in such a
case.To quit t he ti me setti ng, j ust
press the key ZERO.

9.ACCURACY VERIFI CATION

Prior to use , t he F HT te ste r
accuracy sh ould be verif ied by

testing with weights.

FHT accuracy can be easily
verified by the following formula.

P=N/S

Here P is FHT rea ding
N is the force applied to the

plunger tip

S is the area on w hich the

force is applied.
Based on the above formula,
coefficient s are given for
different mod els below.

Model

FHT-801

FHT-802

FHT-803

Tip

3.5mm

3.5mm k=10.3 99

7.9mm

11.1mm

Coeffi cie nt

k=10.3 99

k=2.04 1

k=1.05 3

Apply a f orce N to the ti p.
When r eadi n gs are a l most
u n change d, p res s t he k e y
'MAX' to hold the reading P
w h i c h s hould s atisfy t he
equation b elow.

P=k×N

e.g. if a pplying 0.4 kgf to FHT­801 or 802, the reading shoul d
be

×

0.4 10.399=4.16
Max. deviation is
±(4.16*1%+0.1)=±0.1 4
so correct reading should l ie in

4.16±0.14
=4.02-4.30kgf
But if apply ing 11.0 kgf to

FHT-803 (7.9mm) the readin g

should be
11x2.041=22.45
Max. deviation is
±(22.45*1%+0.1)=±0. 32
so correct reading should l ie in

22.45±0.32
=22.13-22.77kgf

If the deviat ion is bey ond its

accuracy, D epress P ower key

an d not rele ase it till 'C O'

appears o n the Display. It t akes

about 6 seconds from startin g

depressing Powe r key. Then

adjust the reading P by the

'MAX' key (inc rease) or 'UNIT'

key (decrea se) to the desired

value. store that value and quit
by pressing Zero key.

10. COMMUNICATE WITH P C

A． Insta ll the optional R S232C

software to the PC.

B．C onnect th e test er to the COM

or USB po rt of the PC with the
opt io nal RS2 32 cab les . To
connect to a USB port, a USB
adaptor is r equired.

C. Run the software on the desktop

and se lect the C OM port or
U S B p ort i n t h e s yste m
settings .

D . C l i c k t h e b utton o f d at a

coll ec t ion, t h en clic k t he
button of Be gin/Continu e.