Digi-Sense 37950-11 User manual

OPERATION MANUAL

THERMO-HYGROMETER

Model:8903/8904/8906

Model:

8711
8721

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ON

o

o

C / F HOLD

OFF

PRG

RESET

MN / MX

MX / td

MODEL: 8721

ON

OFF MN / MX

o

C / FHOLD

RESET

MODEL: 8711

o

FUNCTION KEYS

1) ON key - Power on

2) OFF Key - Power off

3) PRG Key (8721 only)

- Switch to alarm check mode from
measuring mode

- Switch to alarm setting mode from
alarm check mode

- Save the alarm settings and
calibrations

- Switch to temperature and humidity
calibration

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4) C/ F Key

- Switch between display of C and F

1

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5) RESET Key

- Reset Min/Max memory

- Erase alarm settings

- Skip calibration mode

- Switch back to normal measuring
mode from alarm check mode or
calibration mode

6) HOLD Key

- Hold display

7) MN/MX Key

- Display minimum value of memory

- Display maximum value of memory

- Increase/Decrease the temperature
deviation value

- Sleep/Non-Sleep mode switch

8) NX/td Key (8721 only)

- To flash next digit for alarm setting

- To display the next alarm setting
value

- To flash next digit for calibration

- Dew Point read out

9) 9V DC power jack

10) Probe socket

11) RS232 output socket

QUICK REFERENCE

A. MEASURING MODE

This is the basic function to measure
temperature ( C or F) and relative
humidity.

B. CALIBRATION MODE

With our HR33 & HR75 humidity
reference, the end users can do the
calibration themselves. This feature

oo

provides a DO-IT-YOURSELF
accuracy maintenance and
replacement of the probe.

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C. LOW/HIGH HUMIDITY CALIBRATION MODE

Two points' calibration is necessary for
maintaining the accuracy of the meter.

D. ALARM CHECK MODE

An environment monitoring system
is implanted in the meter for special
uses. A monitoring range can be set
up earlier,the user will be warned for
any out-of-range reading.This Mode
provides you to check the alarm
settings to see if they are under your
requirement.

E. ALARM SETTING MODE

Set, adjust and cancel the alarm
settings.

F. RS232 OUTPUT
To link to the computer gets records.
G. SLEEP MODE OPTION
We have a Non-sleep mode and a 20

minutes sleep mode. You can switch
easily between two.

H. MN/MX MODE
Maximum and Minimum monitoring.

You can find out the minimum and
maximum values of previous recording
simply by pressing MN/MX key
sequentially. The screen will display
Fig. 1 & Fig. 2. Press it again to go
back to normal mode or the meter will
return to normal mode in 10 seconds.

RS232

FIG 1

%RH

o

F

MIN

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RS232

FIG 2

%RH

o

F

MAX

I. HOLD MODE
Hold the screen for specific measuring.

Simply press HOLD key when you do
the measurement. The screen will
display Fig. 3. Press it again to go back
to normal mode.

RS232

FIG 3

HOLD

%RH

o

F

OPERATION MODES

The 8721/8711 provides 6 operation
modes, 3 output port, sleep mode switch

oo

and C/ F switch.

A. MEASURING MODE

This is the normal operation mode for
measuring relative humidity and
temperature in the default unit.
When the power is first on, the full LCD
display will appear as Fig. 4.

Full display will appear for 1 second, then
readings for humidity and temperature,
(Big characters is humidity and small
characters is temperature) will display.
Fig. 5

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FIG 4

td

MAX

HOLD

BAT
MIN

RS232

%RH

RS232

LOTEMP

HITEMP

LO%RH

HI%RH

o

F

o

C

FIG 5

%RH

o

F

B. LOW HUMIDITY CALIBRATION MODE
(The calibration solution is optional,
not included in standard package.)

Two points' calibration is necessary for
the accuracy of the meter.

1. Power off. Push ON & PRG at the
same time and hold till the LCD displays
CAL (Fig. 6). As ON & PRG are
released, the C ( or F, depended on

oo

which is the default unit) will display at the rig
bottom corner (Fig. 7).

FIG 6

FIG 7

o

C

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2. Gently open the cover of HR33 ref.salt.
Insert the probe into the container from
the top until you reach the end.
( Warning: Be very careful and slow
while inserting the probe or pulling it
out. Any rough movement may damage
the Humidity Reference Bottle).

3. Press RESET one time, the 32.X%RH
and MIN will appear on LCD (Fig. 8).
The low humidity calibration will be in
process automatically. This process will
be completed in about 40 minutes with
SA, MAX and MIN shown by LCD display
(Fig. 9). (Warning: Do not touch any
keys before the process is completed.)

FIG 8

%RH

MIN

FIG 9

MAX

NOTE:

The 40 minutes is suggested for a stable
temperature environment. If the
temperature variation is above 0.5 F in
5 minutes, the calibration time will be
extended automatically. It is recommended

MIN

o

to isolate or insulate the standard Humidity
Reference if the environment temperature
is not stable.

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4. After 40 minutes, low humidity
calibration is completed. Now you can
press OFF to end the process or
continue to process high humidity
calibration. To do this, insert the probe
into HR75 and press the NX/td key, the
LCD will display 75.X and MAX (Fig. 10)
which indicates the high humidity
calibration will soon be in process
automatically.

FIG 10

%RH

MAX

NOTE:

A convenient look-up table has been built
in to aid calibration.

HR 33 MgCl

ooooo

TEMP

RH%

If different temperatures, say 25 C, the
RH of MgCl is 32.78 and in 30 C, the RH
is 32.44.
The same reference says 30 C , the RH
of Nacl is 75.09 RH% humidity and in

o

35 C , the RH is 74.87% .(See the table)

15 C 20 C 25 C 30 C 35 C

33.30 33.07 32.78 32.44 32.05

o

o

o

HR75 NaCl

ooooo

TEMP

RH%

The relations are recorded in the look-up
table.
Once the calibration mode in ON,
the meter will search the right humidity
value according to the current tempera­ture to get more accurate calibration.

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15 C 20 C 25 C 30 C 35 C

75.61 75.47 75.29 75.09 74.87

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WARNING!

For Relative Humidity calibration , to
ensure the longer life of the salt bottle
.Keep the bottle in the bag when not in
use and seal the bag tightly .

a. If you are sure of that temperature is
stable and humidity is in equilibrium.
You can reduce the time of the above
process by pressing the PRG key. A
SA will be shown on the screen. Be
very careful with this. If the time
interval is not long enough for unit to
catch the right humidity, whole
measurement later will not be valid.

b. To skip the on-going calibration
process, press RESET. If you are not
sure of the on-going process, press
OFF.

c. After humidity calibration is done, if the
measuring mode displays E2 instead
of the RH and temperature readings,
this means something is wrong.
Please refer to error messages section.

C. HIGH HUMIDITY CALIBRATION MODE

1. There are two ways to enter the high

humidity calibration mode:

a. Turn off the meter. Plug probe into
HR75, then press ON & PRG at the
same time. Hold till CAL is displayed
on screen. Release ON & PRG and
press RESET twice, the LCD will show

75.X% and MAX (Fig. 10). This
indicates that the high humidity
calibration is in automatic process.

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b. When the automatic process for low
humidity calibration is completed, the
LCD displays SA, MAX and MIN
(Fig. 9). Insert the probe into HR75,
then press NX/td. The LCD will show

75.X% and MAX (Fig. 10). This
indicates that the high humidity
calibration is in automatic process.

2. Once the meter starts the automatic
calibration process, do not touch any
key until the meter switches to
measuring mode.

3. To reduce the time for calibration
process, press PRG. Be cautious
with this, refer to NOTE a. of the Low
Humidity Calibration .

4. To skip the on-going calibration
process, press RESET. Turn off the
meter if you are not sure of the on­ going process.

D. ALARM CHECK MODE

1. In measuring mode, press PRG key.

The LCD will display the indicators
LOTEMP, HITEMP, LO%RH, HI%RH
plus XX.Xwith LOTEMP flashing first
(Fig. 11).

2. XX.X is the numeric value previously set
for the flashing indicator. If --- instead
of a reading is displayed, it indicates
that there is no alarm setting for this
option.

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3. Press NX/td key to check the value of
HITEMP(HITEMP is flashing now), and
press NX/td again to check LO%RH ,
and so on.

4. In monitoring range, LOTEMP indicates
the warning point for low temperature.
HITEMP indicates the warning point
for high temperature. LO%RH indicates
the warning point for low humidity.
HI%RH indicates the warning point for
high humidity.

5. Press RESET key to switch the mode
back to the normal operation mode, i.e.
The measuring mode.

LOTEMP

FIG 11

HITEMP

LO%RH

HI%RH

o

F

E. ALARM SETTING MODE

For example, if a user needs to be

alarmed when the temperature reading
goes below 58 F or above 100 and

o

o

F

when the relative humidity reading goes
below 56% or above75%, the user
should set LOTEMP, HITEMP, LO%RH,

o

and HI%RH as follows: LOTEMP=58 ;

o

HITEMP=100 LO%RH=56%; HI%RH

F

F

=75%; Once the meter readings go out
of the range, the alarm will start to beep.
The LCD will also display which indicator
is alarmed. Steps to set up the alarm
are as follows

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1. Power on the meter. When the %RH
reading and the temperature reading
are displayed (Fig. 5). Press PRG to
switch from the measuring mode to
alarm check mode (Fig.11 w/ LOTEMP
flashing).

o

2. Press PRG key, it will display XX as

F

Fig. 12 with " X " flashing. LOTEMP
means we are in low temperature alarm
setting screen.

3. Press NX/td key to change the digital
flash. Press MN/MX and change the

o

number until it displays 58 as Fig. 13.

F

LOTEMP

FIG 12

o

F

LOTEMP

FIG 13

o

F

4. Press PRG key until it displays SA,
release it, the display will show as Fig.
14 with LOTEMP flashing.

5. Press the NX/td key until HITEMP flash.

6. Press the PRG key. Repeat step 2, 3.

Change the number to 45 C. Press

o

PRG to save the setting. It will show
as Fig. 15 with HITEMP flashing.

7. Press NX/td until LO%RH flash as
Fig. 16.

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FIG 14

FIG 15

FIG 16

LOTEMP

HITEMP

LO%RH

HI%RH

LOTEMP

HITEMP

LO%RH

HI%RH

LOTEMP

HITEMP

%RH

LO%RH

HI%RH

o

F

o

F

8. Press PRG, it will display as Fig. 17
with " 5 " flashing.

9. By Pressing NX/td, MN/MX to change
the number to 56. Then press PRG
key to save. It shows as Fig. 18 with
LO%RH flashing.

10. Press NX/td one time and it will flash
HI%RH.

11. Do step 8, 9 but change the number
to 75. It will show Fig. 19 with HI%RH
flashing.

12. Press OFF, turn off the meter or press
RESET (after hearing the beep,
release the key) and goes back to
measuring mode.

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FIG 17

FIG 18

FIG 19

%RH

%RH

LOTEMP

HITEMP

%RH

LO%RH

HI%RH

LO%RH

LOTEMP

HITEMP

LO%RH

HI%RH

13. In measuring mode, if the meter reads

75.1% and 74.9 , it will continue
beeping and display as shown in Fig.

20.LOTEMP, it means temperature is
below our setting. HI%RH, it means
the humidity is above our setting.

14. Cancel setting: when in step 4
(or step 9), if you press RESET and
hold it for 2 seconds and hear beeps.
This means the setting has been
cancelled and it will display as Fig. 21.

LOTEMP

FIG 20

o

F

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NOTE:

You can also cancel the whole setting by
the following: Turn off the meter. Press
RESET and ON at the same time the
meter will display OAL one second as
shown in Fig. 22 with two beeps, then
turns to the normal mode. Thus LOTEMP,
HITEMP , LO%RH,and HI%RH settings
will be cancelled at one operation.

LOTEMP

FIG 21

HITEMP

LO%RH

HI%RH

o

F

FIG 22

F. RS232 OUTPUT(Optional)

Plug the earphone jack of the cable

VZRS232M into RS232 socket on the
meter and connect 9-pin D-sub to the
computer's available COM port. Press
ON key to start measurement. The
VZRS232M is optional accessory.
Contact with the store for more cable
& software purchasing information.

G. SLEEP MODE OPTION

1. In default, if there is no key pressed

in 20 minutes, the meter will go off
automatically. A warning continuous
beep will sound shortly before 20
minutes, press any key can restart the
20 minutes counts.

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2. You can switch the meter to non­ sleep mode by first turn the meter off,
then push and hold MN/MX and ON at
the same time until nSL is displayed as
shown in Fig. 23. Release the key and
you are in Non-Sleep mode.

oo

H. C/ F SWITCH MODE
You can change the C/ F display

oo

anytime you want by pressing the

oo

C/ F key during operation. You can
also change the default display by the
following:
For example, if the meter default to F,

o

while turning off the meter, press PRG
& ON at the same time until CAL is
shown in one second, then release the
keys. F will display on the right bottom

o

corner of the LCD. See Fig. 24

Press MN/MX to change F to C ,then

o

o

press PRG until it displays SA in one
second and XX.X%RH and MIN will
appear on the left corner , turn off the
meter. Now when you turn on the meter,
it will default to C

o

FIG 23

FIG 24

o

F

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ERROR MESSAGES

1. Display OP with continuous beeps
as shown in Fig. 25:
Probe is not connected in the right
position.

2. Display 0.0%, 99.9% for a long
period of time:
Probe damaged. Please replace a
new probe.

3. Display Er 1, Er 2, Er 3 and Er 4
with a beep as shown in Fig. 26:

Er 1, Er 3 and Er 4: Circuit error
Er 2: Improper calibration; Probe
damaged

4. Screen flashing:
It means battery is weak, the batteries
needs to be replaced .

FIG 25

FIG 26

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TECHNICAL SPECIFICATION

1.Humidity measurement range:
8711: 5%-95%
8721: 0%-100%
Temperature measurement range:
8711: -10~50 C
8721: -20~50 C

2.Humidity Accuracy:
2% from 0~95% at 25 C (8721)
3% from20~90% at 25 C (8711)

Temperature Accuracy:
1 C from -20~50 C

3.RS232 output: Baud rate: 1200bps
Data bit: 7 ,
Stop bit:1 ,
Parity: None
Format:

4.Storage Temperature: -20 C to 60 C

TXXX.XC(F):HXX.X%

oo

5.Operating Temperature: 0 C to 50 C

oo

6.Power requirements: Single 9V battery

7.Battery life: 100 hours typical (alkaline)

8.Optional accessories:
a. Calibration salt
VZ0033AZ or VZ0033AZ1 for 33%
VZ0075AZ or VZ0075AZ1 for 75%
b. RS232 cable with software CD.

9.This package contains :
a. Meter x1 b. Hard carry case x 1
c. Battery 9 volt x 1
d. Operation instruction x 1

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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
shipment and insured against possible
damage or loss .

WARRANTY

The meter is warranted to be free from
defects in material and workmanship for
a period of one years from the date of
purchase.

This warranty covers normal operation
and does not cover batteries,misuse,
abuse, alteration, tampering, neglect,
improper maintenance, or damage
resulting from leaking batteries.
Proof of purchase is required for
warranty repairs.

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2006/07,1000

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