USER MANUAL USB Multi-Function Datalogger Model RHT35 Additional User Manual Translations available at www.extech.
Introduction Thank you for selecting the Extech multi-function, easy-to-use, portable USB datalogger. The RHT35 offers temperature, humidity, and pressure logging. The USB datalogger can be configured and customized by the user by plugging it into a PC USB port, following the on-screen prompts, and making selections on the supplied ‘PDF Logger Configuration Tool’. This device is shipped fully tested and calibrated and, with proper use, will provide years of reliable service. Please visit our website (www.
8. USB plug. 9. Battery compartment (CR2032 x 2) on rear. 10. Wall hanging mount (rear). Mounting screw supplied. Button Descriptions POWER button. Short press to power ON or OFF. Note that the datalogger cannot be switched OFF while datalogging is in progress. START/STOP button (same physical button as the Power button above). Press and hold for 5 seconds to start or stop the datalogger. Note that the datalogger will not start unless it has been configured using the ‘PDF Logger Configuration Tool.
Display (LCD) Description oF oC RH% T1 H L REC Temperature unit of measure as programmed by the user Displayed when showing Relative Humidity reading Represents the internal sensor (air) temperature High Alarm triggered Low Alarm triggered REC flashes once per second when actively datalogging.
PDF Logger Configuration Tool Connect the datalogger to PC USB port. The PC will prompt to view files. Open the ‘PDF Logger Configuration Tool’ from the list of available files. Refer to the Operation Section for additional details on this tool: 2 3 1 4 5 15 6 14 7 13 8 9 10 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15.
Operation NOTES: 1. Adobe Reader® software is required. 2. Ensure the logger is at room temperature before inserting it into a PC port. 3. The executable file for programming is named “PDF Logger Configuration Tool”. 4. A datalogging session cannot start until the datalogger is properly configured. Configuring the RHT35 for a Datalogging session At any time before logging is started, the logger can be programmed and re-programmed. The previous logging session will be deleted once a new session is started.
• Alarm Modes Single Event Alarm mode: The LED immediately starts flashing red every 10 seconds when the measured value exceeds the alarm threshold. Cumulative Alarm mode: The LED begins flashing red only after the average value exceeds the alarm threshold and also after any programmed Alarm Delay time. See Alarm Delay parameter above. Alarm Disable (default): Alarm function disabled.
Start Datalogging 1. Configure the logger as previously described and then hold the Start/Stop for 5 seconds to start logging. button 2. Measurements update on the display every 10 seconds. The temperature, %RH, and pressure measurements toggle every 5 seconds. 3. If the logger is programmed with a Start Delay: After pressing and holding the Start/Stop button for 5 seconds to start logging, REC will appear on the LCD but will not flash until the delay time has elapsed and logging has begun. 4.
Specifications Display (LCD) 5-digit LCD with multi-function indicators Status indicator (LED) Dual color multi-purpose LED (red/green) for active logging, alarms, and PC connection status Temperature Sensors NTC Thermistors Temperature Range -30 ~ 70oC (-22 ~ 158oF) Temperature Resolution 0.1oC/oF Temperature Accuracy ±0.5oC (0.9oF) Humidity Sensor Capacitive (Relative Humidity) Humidity Range 0.1 ~ 99.9%RH Humidity Resolution 0.
Maintenance Battery Replacement The battery compartment is located on the back of the datalogger as shown in the Descriptions section. When the battery symbol flashes on the display, replace the batteries promptly. 1. Using a large coin, rotate the battery compartment lid clockwise approximately one quarter turn to open the compartment 2. Replace the two (2) CR2032 batteries with positive (+) side facing up 3. Replace the battery compartment lid and turn counterclockwise to secure it 4.
