OPERATING INSTRUCTIONS
HH804U
DUAL INPUT RTD THERMOMETER
®
HH804U
MADE IN TAIWAN
INTRODUCTION
This instrument is a 4_ digit,
SAFETY INFORMATION
It is recommended that you read the safety and operation 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 take temperature measurements in micro-
wave ovens.
ENVIRONMENTAL
Ambient Operating Ranges:
0°C to 50°C (32°F to 122°F) <70% R.H.
Storage Temperature:
GENERAL
Display:
4_ digit liquid crystal display (LCD) with maximum reading of 19999 Overload:
Battery:
1.5V x 4 PCS (SIZE AAA) R03P.
Battery Life:
200 hours typical with carbon zinc battery Auto power off: 30 minutes
Dimensions:
160mm(H) x83mm(W) x 38mm(D) Weight: Approx. 255g including batteries.
SPECIFICATIONS
ELECTRICAL
Temperature Scale: Celsius or Fahrenheit
Measurement Range:
Pt385(100_)
Pt3916/Pt3926(100_)
Resolution: 0.1°C or 0.2°F
Accuracy:
Accuracy is specified for operating temperatures over the range of 18°C to 28°C (64°F to 82°F), for 1 year, not including RTD probe error.
±(0.05% rdg + 0.2°C) on °C scale ±(0.05% rdg + 0.4°F) on °F scale
Temperature Coefficient:
0.1times the applicable accuracy 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).
Input Protection:
24V dc or 24V ac rms maximum input voltage on any combination of input pins.
Maximum Differential Common Mode Voltage (Maximum Voltage be- tween T1 and T2 during measurement): 1volt.
Reading Rate: 1sample/second.
Input Connector:
Accepts 4 pin
OPERATING INSTRUCTIONS
1. 
Power Button
The 
button turns the thermometer on or off. In the SET mode the unit cannot be powered off. Exit the SET mode to power off.
APO function mode
Press “ ” power button for more than 6 seconds to disable auto power function. The display will show “APO OFF”.
2.°C/°F Selecting the Temperature Scale (Main display)
Readings are displayed in either degrees Celsius(°C) or degrees Fahren- heit(°F). When the thermometer is turned on, it is set to the temperature scale that was in use when the thermometer was last turned off. To change the temperature scale, press the °C/°F key.
3.“ ” Display
Press the “ ” key to turn on or turn off the back light.
4.T1 T2/T1-T2 Main display Input Selection
The input selection button determines which input is shown on the display; T1 ,T2 or the difference between the two probes
5.TYPE(Pt385/Pt3926/Pt3916) Input RTD Probe Select (Main display) The TYPE button selects the RTD curve to use for the input currently shown. When the thermometer is turned on, it is set to the curve that selected when the thermometer was last turned off.
6.MIN MAX with Time record Mode (only Main display)
Press MIN MAX key to enter the MIN MAX Recording mode, (displays Maximum reading with time, Minimum reading with time and Average reading stored in recording mode). In the this mode the automatic
feature is disabled and key, °C/°F key, REL key, SET key, Hi/Lo Li key and main display T1 T2 T1- T2 key, TYPE key are disabled. beeper emits a tone when a new minimum or maximum value is recorded. Push MIN MAX key to cycle through the MAX, MIN and AVG readings. If an overload is recorded, the averaging function is Stopped. In the mode, press HOLD key to stop the recording of readings, all values are zen, press again to restart recording. To prevent accidental loss of MAX and AVG data, in this mode can only be cancelled by pressing hold down the MIN MAX key for 2 seconds to exit and erased recorded readings.
7.REL Relative mode (only Main display)
Press REL key to enter the Relative mode, zero the display, and store displayed Reading as a reference value and annunciator REL is displayed. Press REL key again to exit the relative mode. The relative value can
be entered by the user. (See “SET mode”later in this manual.) When the sired Relative value has been entered, press REL key to enter the Relative mode, press SET key use set Relative value as a reference value. Press key again to exit the relative mode. In the Relative mode, the value (can >±1999.9 counts) shown on the LCD is always the difference between 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 sent readings and stops all further measurements. Press the HOLD again to cancel HOLD mode causing thermometer to resume taking ureents. In the MIN/MAX recording mode, press HOLD key to stop the cording. Press HOLD key again to resume recording. (Previously recorded read are not erased).
9.SET mode (Relative value set, Time set and Hi/Lo Limits value set)
Press SET key to enter Relative values SET mode (Press ENTER key escape relative values set mode), REL set mode. = = = =.= is displayed main display. Relative value is entered via overlay numbers, then
