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OPERATING INSTRUCTIONS
MODEL 804R
DUAL INPUT RTD THERMOMETER
INTRODUCTION
This instrument is a 4½ digit, compact-sized portable
digital thermometer designed to use external 100
Ω
Plati-
num RTD as temperature sensor. Temperature indication
follows Reference Temperature/Resistance Tables (Pt385
for European Curve, Alpha=.00385. Pt3926 for American
Curve, Alpha=.003926.)
Features of the instrument include:
y
Dual Input Function
y
Pt3926/Pt385 RTD Standard
y
According to temperature standard ITS-90
y
Resistance Measurement
y
One-second measurement cycle
y
Real Time indicate
y
MAX/MIN with elapsed time
y
AVG, REL, HOLD function
y
Warning beeper with Hi/Lo setting
y
Time setting
y
REL Setting
y
°C/°F user-selective
y
Temperature resolution: 0.1°C or 0.1°F
y
Reading Resistance resolution: 0.1
Ω
y
Reading Resistance resolution by PC: 0.01
Ω
y
Multiple signal: 3000 samples with start-time data
y
Single signal: 32 samples with real-time data
y
Support user-linear table setting by PC
y
USB Mini-B interface standard
y
Optional 12V DC power
SAFETY INFORMATION
It is recommended that you read the safety and opera-
tion instructions before using the thermometer.
WARNING
To avoid electrical shock, do not use this instrument
when working voltages at the measurement surface
over 24V AC or DC.
WARNING
To avoid damage or burns, do not make temperature
measurement in microwave ovens.
SPECIFICATIONS
ELECTRICAL
Temperature Scale:
Celsius or Fahrenheit user-selectable.
Measurement Range:
Pt385(100
Ω
) -200°C to 800°C, (-328°F to 1472°F)
Pt3926(100
Ω
) -200°C to 630°C, (-328°F to 1166°F)
Temperature Resolution:
0.1°C or 0.1°F
Temperature Accuracy:
±(0.05% rdg + 0.2°C) on °C scale
±(0.05% rdg + 0.4°F) on °F scale
Accuracy is specified for operating temperatures over the
range of 18°C to 28°C (64°F to 82°F), for 1 year, not in-
cluding RTD probe error.
Temperature Coefficient:
0.1 times the applicable accu-
racy specification per °C from 0°C to 18°C and 28°C
to 50°C (32°F to 64°F and 82°F to 122°F).
Resistance Range:
0 to 400
Ω
Resistance Resolution:
0.1
Ω
(Meter Reading)
0.01
Ω
(PC Reading)
Resistance Accuracy:
±(0.05% rdg + 2dgts) Meter Reading
±(0.05% rdg + 4dgts) PC Reading
Input Protection:
24V dc or 24V ac rms maximum input
voltage on any combination of input pins.
Input Connector:
Accepts for RTD 4 wires subminiature
4-Prong type connectors.
Maximum Differential Common Mode Voltage:
1volt. (Maximum Voltage between T1 and T2 during
measurement)
Back Side:
1. USB Port
2. DC power JACK(12V)
ENVIRONMENTAL
Ambient Operating Ranges:
0°C to 50°C (32°F to 122°F) <70% R.H.
Storage Temperature:
-20°C to 60°C (-4°F to 140°F) <80% R.H.
GENERAL
Display:
4½ digit liquid crystal display (LCD) with
maximum reading of 19999.
Overload:
“----.-”or “OL” is display.
Battery:
1.5V x 4 PCS (SIZE AAA) UM-4 R03.
Battery Life:
120 hours typical with carbon zinc battery.
Reading Rate:
1 times per second.
Auto Power Off:
30 minutes, press power key to resume
operation.
Dimensions:
160mm(H) x 83mm(W) x 38mm(D).
Weight:
Approx. 260g including batteries.
OPERATING INSTRUCTIONS
1. “ ”
Power Switch
The “ ” key turns the thermometer on or off. In the
SET mode can not be powered off. Exit SET mode to
power off.
APO function mode
Press “
” power key for more than 6 seconds to
disable the auto-power function. The display will show
“APO OFF”.
2. “°C/°F/
Ω
” Selecting Button
To change the scales of °C/°F/
Ω
, press the “°C/°F”
key to cycle through °C, °F and
Ω
. When the ther-
mometer is turned on, it is set to the temperature scale
that was in use when the thermometer was last turned
off.
3. “ ” Display Back-Light
Press the “
” key to turn on or turn off the
Back-Light.
4. “T1 T2/T1-T2” Main display Input Selection
The input selection indicates which input is selected
for main display; T1 probe, T2 probe or the difference
between the two probes (T1-T2). When the thermometer
is turned on, it is set to T1, when main display input se-
lected T1, then T1 input can select alternate of probe by
pressing “Pt385/Pt3926” key switch.
5. “TYPE” (Pt385/Pt3926)Main display Input
RTD Probe Select
The “TYPE” key switches the T1 input to select the
Pt385 or Pt3926 or User Liner RTD probe as input
when main display input selected T1. It is invalid for the
selection of these parameters when the main display se-
lects T1-T2. When the thermometer is turned on, it is set
to the probe selected that was in use when the ther-
mometer was last turned off. Switch flow: Pt385,
Pt3926, User Linear.
(*)User Linear please refer section 16.
6. “MAX/MIN”
With Time record Mode (only Main display)
Press “MAX/MIN” key to enter the MIN MAX Re-
cording mode, (displays the Maximum reading with
time, Minimum reading with time and Average reading
stored in recording mode). In the this mode the auto-
matic power-off feature is disabled and “
” key,
“°C/°F” key, “REL” key, “SET” key, “Hi/Lo LIMITS”
key and main display “T1 T2 T1- T2” key, “TYPE” key
are disabled. The beeper emits a tone when a new
minimum or maximum value is recorded.
Push “MAX/MIN” key to cycle through the MAX,
MIN and AVG readings.
If an overload is recorded, the averaging function is
stopped. In this mode, press “HOLD” key to stop the
recording of readings, all values are frozen, press again
to restart recording. To prevent accidental loss of MAX,
MIN, and AVG data, this mode can only be cancelled
by pressing and holding the “MAX/MIN” key for 2
seconds. All recorded readings are erased.
7. “REL” Relative Mode(only Main display)
Press the “REL” key to enter the relative mode, zero
the display, and store the displayed Reading as a refer-
ence value. REL is shown on the display. Press “REL”
key again to exit the relative mode. The relative refer-
ence value can also be entered by the user. (See “SET
mode” later in this manual). When the desired relative
value has been entered, press “REL” key to enter the
relative mode and than press “SET” key use the entered
relative value as a reference value. Press “REL” key
again to exit the relative mode. In the relative mode, the
value (can not >±1999.9 counts) shown on the LCD is
always the difference between the stored reference and
the present reading.
8. “HOLD” Mode(only Main display)
Press the “HOLD” key to enter the Data Hold mode,
the “HOLD” annunciator is displayed. When HOLD
mode is selected, the thermometer held the present
