MODEL 306 DUAL CHANNEL DATALOGGING THERMOMETER
4.0Operating Instructions:
4.1Preparation for Measurement
Plug the first thermocouple into the socket marked T1, taking care to observe the polarity of the thermocouple pins. If dual sensors are being used, plug the second thermocouple into the socket marked T2.
4.2Power
Press the 
button to turn the thermometer ON or OFF.
When first powered on, the LCD will show how much memory
space is available for use.
Example: Display at right indicates 16,000 records of available memory.
4.3Selecting the Temperature Scale
When first turned on, the instrument defaults to reading in Celsius (°C). The instrument toggles between Celsius (°C) and Fahrenheit (°F) each time the °C/°F button is pressed. The instrument remembers the scale setting when last turned off and powers on in that setting the next time.
4.4Data-Hold Function
The present reading is held on the display by pressing the HOLD button. Pressing the HOLD button again releases the hold function and returns the instrument to continuous reading.
In the HOLD mode, the TIME, MAX MIN and °C/°F buttons are disabled, as indicated by two consecutive beeps when pressed.
4.5Clock Setup
To set the real time clock:
1. Press and hold the MAX MIN button and then power on the meter.
2. Press TIME (clock).
3. Press REC (ν) or °C/°F (π) to increase or decrease the number.
4. Press TIME to move to the next item. The adjusting order is: year; month; day; hour; minute.
5.Press TIME again after the last setting to complete the process. To abort during a setup process, press the 
button.
4.6Time Function
Once set up, pressing the TIME button displays time as follows: top of the LCD – year; bottom left of the LCD - month and day; bottom right of the LCD - hour and minute. Press the TIME button or any other button to exit this mode. This operation will not interrupt the recording and MAX/MIN operation.
4.7Recording Interval Setup
To set the recording interval:
1. Press and hold the MAX MIN button and then power on the meter.
2. Press HOLD.
3. Press REC (ν) or °C/°F (π) to increase or decrease the number.
4. Press HOLD to advance to the next item.
5. Press HOLD again after the last setting to complete the process. | ||
To abort during a setup process, press the | button. | |
MODEL 306 DUAL CHANNEL DATALOGGING THERMOMETER
4.8 Recording Data
Each momentary press of the REC button will alternately start and stop recording. To clear the memory, power off the meter, press and hold the REC button followed by the 
button, holding both on simultaneously for at least 2 seconds. Then release both buttons. The display will show "CLR" (as shown to the right) indicating that the memory has been cleared.
4.9MAX/MIN Operation
Press the MAX MIN button to enter the MAX/MIN mode. In this mode, both the maximum and minimum values are simultaneously retained in memory and updated with every new data sample. The instrument first enters the MAX mode, and the MAX symbol and value are both displayed. Pressing MAX MIN again advances the display to the MIN symbol and value. The next press of the MAX MIN button will cause both the MAX and MIN symbols to flash. This indicates that the maximum and minimum values have been updated in memory and the displayed reading is the present temperature. Each successive press of the MAX MIN button circulates the display mode among these options. To exit the MAX/MIN mode, press and hold the MAX MIN button for two seconds. In the MAX/MIN mode, the °C/°F button is disabled, as indicated by two consecutive beeps if pressed.
4.10Auto Power Off
By default, the instrument powers on in the ‘Auto Power Off’ mode and will automatically shut off 30 minutes after the last key operation or RS232 communication.
To disable this feature, press and hold the HOLD button and then power on the meter.
Two successive beeps will indicate that ‘Auto Power Off’ is disabled, and the 
will not be displayed.
4.11Low Battery Condition
When the battery voltage is at or below the minimum for proper operation, the
symbol will show on the LCD indicating that the battery must be replaced.
4.12Calibration
Calibration is conducted by adjusting the following potentiometers to within the tolerances shown.
(Ambient Temperature: 23 ± 3°C)
Input | Adjust VR | Tolerance | A simple single point calibration may be | |
0 | °C | VR1 | ± 0.1 °C | performed by adjusting VR1 to 0 °C with |
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190 | °C | VR2 | ± 0.1 °C | thermally stabilized ice water. |
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1000 | °C | VR3 | ± 1 °C |
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1900 °F | VR4 | ± 1 °F | TX RX GND | |
4.13 Digital Output |
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The Digital Output is a 9600 bps N 81 serial interface. | ||||
RX is a 5V normally high input port. |
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TX is a | 5V normally high output port. |
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Appendix: Thermocouple Probe Specifications |
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Model |
| Range | Tolerances | Description |
| ±2.2°C or ±0.75% | Teflon insulation. Maximum insulation | ||
Wire probe | ±3.6°F or ±0.75% | temperature: 260°C (500°F) | ||
Probe for general condition measurements, especially for complex and hard to reach places.
3 | 4 |