OPERATION MANUAL
HEAT INDEX WBGT METER
8758
Model:
8778
8758
8778
INTRODUCTION
Thank you for purchasing the Heat Index
WBGT meter. The handy meter measures
air temperature, globe temperature, and
humidity to give heat stress index for
using in control of physical activity in hot
environment to limit the danger of heatrelated injuries
WBGT(wet-bulb globe temperature) was
developed as a monitoring basis at US
military training camps and became
widespread for the use in workplaces
and sports situations. It is suggested in
an international standard ISO 7243 and
many governments such as OSHA (US
Occupational Safety & Health Administration), SMA(Sports Medicine Australia),
and Japan Society for Occup ational
Health in establishing the permissible
heat exposure limits in occupational
health, sports or other physical activities.
(See appendix)
The applications of the heat index can be
in construction, iron and steel foundries,
bricks-firing plants, glass facilities, boiler
rooms, mi ning sites, army tra ining,
marathon, beach activities and so on.
Featu res:
Direct measu remen t of the ra diati on
effec t with a br ass bla ck ball .
Adjustable W BGT ala rm thre shold
Audible beeper for he at stre ss
monit oring
Sensor prote cting m echan ism
Easy se lf cali brati on for hu midit y
PC connect for d ata ana lysis
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CONTROLS AND INDICATORS
LCD dis play
Symbo l indic ation
WBGT Wet Bul b Globe Temper ature
TG Blac k Globe Tem perat ure
TA Air Tem perat ure
% Relat ive Hum idity
C/F Cel sius/ Fahre nheit
IN Indo or (no su n)
OUT Out door (full sun)
Low bat tery in dicat or
DP/RE C Vain ico ns in the se
model s.
Funct ion Key s
Turn on an d off the m eter
Enter a larm se tting m ode
NEXTNEXT
Selec t digit i n setti ng mode
Exit fr om sett ing mod e
MODEMODE
Selec t displ ay mode
Shift I N/OUT mode
Incre ase val ue in set ting
MODEMODE
+ Set as no n-sle ep
MODEMODE
NEXTNEXT
+ Selec t C or F
+ + Enter R H calib ratio n
MODEMODE
NEXTNEXT
o
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OPERATING INSTRUCTIONS
Pul l up to
pro tect se nsor
Des ign pat ent
pen ding
1. POWER ON/O FF
Press t o turn on a nd turn o ff the
meter. Al l indic ators a re show n on
the LCD w hen pow er on, an d then
enter m easur ing mod e.
2. MEASUREM ENT
Slide d own the p rotec ting sh eath
of sens or befo re meas ureme nts.
Selec t displ ay mode
The met er meas ures TA(A ir Temp),
TG (Glo be Temp .), RH (R elati ve
Humid ity), a nd calc ulate s WBGT.
Press t o selec t modes . An icon
shows o n the top t o indic ate the
curre nt oper ation m ode. (F ig. A)
MODEMODE
Fig. A
IN/OU T switc h
To measur e WBGT witho ut or wit h
direc t sun exp osure u nder IN /OUT
modes , hold do wn for mo re
MODEMODE
than 1 se cond to s witch .
Selec t Unit
Press a nd simu ltane ously i n
measu ring mo de to sel ect C or
MODEMODE
NEXTNEXT
o
o
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F.
3. ALARM SETTING
The met er feat ures au dible a larm
to give w arnin g for pos sible h eat
stres s in the en viron ment. W hen
WBGT va lue rea ches th e alarm
thres hold, t he valu e start s to blin k
with co ntinu ous bee p(abo ut 70 dB) .
The ala rm stop s when me asure d
value f alls be low the t hresh old or
the met er is tur ned off.
The ala rm thre shold i s adjus table
for dif feren t appli cations. Hold
down fo r 2 secon ds to tur n on
the met er and en ter ala rm sett ing.
The cur rent se tting displays with a
blink ing dig it. Pre ss to inc remen t
the val ue and to s elect d igit.
MODEMODE
NEXTNEXT
After ne w alarm t hresh old is se t,
press f or 2 seco nds to re turn to
NEXTNEXT
measu ring mo de.
The set ting ra nge is 20 .0~37 .2 C
(68.0 ~99.0 F). "O UT" wil l show if
o
o
setti ng is out o f range . (Fig. B )
Fig. B
4. BATTERY RE PLACEMENT
appea rs on the L CD when b atter y
volta ge gets l ow. To repla ce batt ery
by open ing the c ompar tment o n the
rear of t he mete r.
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5. AU TO POWER OF F
The met er turn s off automatically
after 2 0 minut es non- opera tion.
To overri de the fu nctio n, hold d own
and for 2 s econd s to turn o n
MODEMODE
the met er. The LC D will di splay “ n”
and the n enter m easur ing mod e.
(Fig. C )
Fig. C
6. TRIPOD MOU NTING
The met er can fi t on a tripod for long
time mo nitor ing. A buil t-in th read is
on the re ar side o f the met er.
RH CALIBRATION
The met er can be c alibr ated on t he
humidity by en d users w ith 33% a nd
75% salt solut ion. Th e ambie nt
condition is r ecomm ended t o be at
o
23+/- 2 C and stable humidity. Users
can ter minat e the cal ibrat ion any time
by turn ing off t he mete r.
Unscrew the bl ack
globe with sen sor
sheath (see pi c. A)
befor e calib ratio n.
Follo w the ill ustra tion
on page 7 to recap
sensor sheat h after
completing c alibr ation .
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Black globe
with sensor
sheath
Sensor
connector
Sensor
probe
Pic. A
Salt so lut ion
Pic.A 1
33% calibration
Plug the sensor pro be into 33% salt
bottle(Pic A1), hol d down , ,and
MODEMODE
NEXTNEXT
buttons for 2 secon ds to power on the
meter until blink ing “3X.X%” ap pears.
Meter is now calibr ating, and wil l finish
in about 60 mins. whe n the value stop s
blinking.
Not e:
Str ongly recomm end to use one han d to
press one button, a nd use two finge rs
of th e other hand to pr ess two button s
simultaneousl y . This is eas ier for you
to op erate 3 keys.
75% calibrat ion
After 3 3% cali brati on, plu g the sen sor
probe into 75% s alt bot tle, th en pres s
MODEMODE
for 2 sec onds to s tart.
The bli nking “ 7X.X% ” shows o n the
screen and meter is now c alibr ating .
Wai t about 6 0 mins. until b linki ng stop s
,it mea ns the ca libra tion is c omple ted
and meter retu rns to me asuri ng mode .
Note:
The RH va lue dif feren ce betw een the
meter d ispla y and cal ibrat ion sta ndard
should be with in +/-0 .3%, ot herwi se
it is a fai led cal ibrat ion.
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CAUTION:
Reassemble the globe with caution by
fitting the pin (Pic. B) into the connector
(Pic.C). It helps to position by targeting
the screw holes on the sheath and the
meter. Incorrect installation may
damage the sensor.
Sen sor
pin
Pic.B
Sen sor
connec tor
Pic .C
Imp ort ant :
Screw ho les
for t arg eti ng
to as semble
the g lobe.
Pic. D
TROUBLESHOOTING
? Power on but no display
Check whether the batteries are in
good contact and correct polarity, or
take out the batteries for one minute
and reinstall and retry.
? Calibration failure
a.Check the battery voltage or replace
with new batteries.
b.Check whether the sensor is well
plugged into the salt bottle and no air
comes in. Check ambient condition.
? Error message on the display
E2: The value is under range. Improper
sensor installation.
E3: The value is over range.
E4: The value is in error because of
the original data. Improper sensor
installation.
E11: RH calibration error. Do the
calibration again.
E32/E33: Circuit error. Return to the
vendor for repair or replacement.
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RS232 INTERFACE
8758 8778
Black ball size
40(D)x35(H)mm 75(D)x75(H)mm
Air Temp. range
0~50℃ (32~122℉)
Air Temp. accuracy
±0.6℃
Globe Temp. range
0~80℃ (32~176℉)
Indoor
±2℃ (15~40℃)
±2.5℃ (Others)
±1℃ (15~40℃)
±1.5℃ (Others)
Globe
Temp.
accuracy
Outdoor
±3℃ (15~40℃)
±3.5℃ (Others)
±1.5℃ (15~40℃)
±2℃ (Others)
WBGT Temp. range
0~50℃ (32~122℉)
WBGT Formula
Indoor/Outdoor and no sun:
WBGT=0.7WB + 0.3TG
Outdoor and full sun:
WBGT=0.7WB + 0.2TG + 0.1TA
RH range
0~100%
RH accuracy
±3% (10~90%RH)
±5% (other range)
Resolution
0.1℃/℉, 0.1%RH
Response time
15 seconds typical
Operating condition
0~50℃, 0~95% RH
Storage condition
-20~65℃, 0~95% RH
Meter size
40(H)x48.7(W)x254(L)mm – 8758
75(H)x75(W)x278.2(L)mm – 8778
Battery life
(without beep)
1000 hours (Alkaline)
250 hours (General purpose)
The met er can do P C link fo r
logging and via RS232
data an alysi s
inter face an d softw are.
The pro tocol i s as foll ows.
A.9600 bp s, 8 data bit s, n o parit y.
B.For mat
(Tr ans mit tin g ASCII code by ever y
secon d whi le me ter i s on. )
Wxxx. xC(F) :Txxx .xC(F ):Txx x.xC( F)
:Hxx. x%LRC CRLF
Note: The 1st value is W BGT, th e 2nd i s
TA, th e 3rd i s TG, a nd th e 4th i s RH.
on-line
SPECIFICATION
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MATERIALS SUPPLIED
This pa ckage c ontai ns:
Meter
2pcs AAA ba tteri es
Opera tion ma nual
Plain box packaging
Optio nal acc essor y:
33% calibration sal t (HR33 )
75% calibration sal t (HR7 5)
RS232 cable and softw are(ASFTKIT)
WARRANTY
The meter is warranted to be free from
defects in material and workmanship
for a period of two years from the date
of purchase. This warranty covers
normal operation and does not cover
misuse, abuse, alteration, neglect,
improper maintenance, or damage
resulting from leaking batteries. Proof
of purchase is required for warranty
repairs. Warranty is void if the meter
has been opened.
RETURN AUTHORIZATION
Authorization must be obtained from
the supplier before returning items for
any reason. When requiring a RA
(Return Authorization), please include
data regarding the defective reason,
the meters are to be returned along
with good packing to prevent any
damage in delivery and insured against
possible damage or loss.
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APPENDIX
Recom men dat ion s to he at exposure lev el
for wor kin g and p hys ica l activity!
PERMIS SIB LE HE AT EXP OSU RE THRESHOLD LIMIT
Valu e:W BGT
Wor k/re st regi men Light Moder ate H eav y
(Ea ch hour )
Con tinuo us work 3 0 C 2 6.7 C 2 5 C
/86 F /8 0 F / 77 F
75% w ork, 25 % rest 30.6 C 28 C 2 5.9 C
/87 F /8 2 F / 78 F
50% w ork, 50 % rest 31.4 C 29 .4 C 27 .9 C
/89 F /8 5 F / 82 F
25% w ork, 75 % rest 32.2 C 31 .1 C 30 C
/90 F /8 8 F / 86 F
Sou rce: AC GIH 19 92( The Am eri can Co nfe ren ce
of Go ver nme ntal I ndu str ial Hy gie nis ts)
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WBGT INDEX AN D PHY SICAL EX ERCISE
WBGT Flag Act ivi ty Intensity
o
< 80 F Wh ite N ormal activit y. Caution
o
< 26. 7 C should be ta ken .
o
80- 84.9 F Gr een Discretio n is re qui red
o
26. 7-29. 4 C in plan nin g int ens e
physical a cti vit y.
o
85- 87.9 F Yell ow Intense a
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29. 4-31 C an d una cclimati zed
persons sh oul d be
curtaile d.
o
88- 89.9 F Re d Int ens e exercise must
o
31- 32.2 C be c urt ailed for those
with less th an 12 w eek s
training i n hot w eat her.
Be on high ale rt
o
> 90 F Bl ack C ancel all outdo or
o
> 32. 2 C exercise .
Sou rce: Ma nual of Nava l Pre vent ive M edi cine
(NAV MED P -50 10)
ctivi ty fo r new
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