Extech Instruments RH520B User Manual

2 RH520B-en-US_v5.2 8/20
Introduction
Congratulations on your purchase of the Extech RH520B Temperature + Humidity Chart
Recorder. The RH520B measures and displays Temperature, Humidity, and Dew Point.
The remote (detachable) probe senses the ambient conditions while the LCD display graphs and
provides numerical representation of the readings. Programmable audio-visual alarms alert the
user when ambient conditions reach alarm presets. The optional alarm module permits
automatic relay switching when alarm presets are reached.
The RH520B Internal Memory can store up to 49,152 measurements for later transfer to a PC.
Careful use of this instrument will provide years of reliable service.
CAUTIONS
 This device is not a toy, it contains hazardous objects as well as small parts that children can
swallow. Contact a physician immediately if an object is swallowed.
 Do not leave batteries or packing material unattended; they can be dangerous to children.
 If the device is to be unused for an extended period, remove the batteries to prevent them
from draining.
 Expired or damaged batteries can cause cauterization on contact with the skin. Use
protective gloves when necessary.
 Do not short-circuit batteries or discard them in a fire.
FCC Compliance
This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to
part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful
interference in a residential installation. This equipment generates, uses, and can radiate radio frequency
energy and, if not installed and used in accordance with the instructions, may cause harmful interference to
radio communications. However, there is no guarantee that interference will not occur in a particular
installation. If this equipment does cause harmful interference to radio or television reception, which can be
determined by turning the equipment off and on, the user is encouraged to try to correct the interference by
one or more of the following measures:
1. Reorient or relocate the receiving antenna.
2. Increase the separation between the equipment and receiver.
3. Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
4. Consult the dealer or an experienced radio/TV technician for help.
WARNING
Changes or modifications not expressly approved by the party responsible for compliance could void the
user's authority to operate the equipment.

Extech Instruments RH520B Specifications

General

Humidity Range	0 to 100% RH
Dew Point	Yes
Wet Bulb	Yes
Datalogging	Yes
Sampling Rate	1 second
PC Interface	USB
Data Hold	Yes
Auto Power Off	Yes
Warranty	1 Year
Resolution	0.1°F/°C; 0.1%RH
Accuracy Temperature	±1.0°C
Display	LCD

Summary

Introduction

CAUTIONS

Safety precautions and warnings regarding device usage, battery handling, and potential hazards for users.

FCC Compliance

Information on the device's compliance with FCC rules for digital devices and potential radio frequency interference.

Getting Started

POWER

Details on how the RH520B operates on battery or AC power, including battery replacement advice.

MOUNTING THE RH520B

Instructions for placing the device on a table or mounting it on a wall using the provided holes.

MEASUREMENT PROBE

Information about the detachable sensor probe, its cable, and potential extension methods.

PUSH-BUTTON LOCK-OUT SECURITY FEATURE

Procedure to lock and unlock the device's push-buttons to prevent tampering or accidental changes.

Programming the RH520B

SETTING THE TIME AND DATE

Step-by-step guide to setting the device's internal clock and date for accurate logging.

CLEARING THE INTERNAL MEMORY

Instructions on how to reset display parameters and clear stored readings or alarm history.

SELECTING THE UNIT OF MEASURE FOR TEMPERATURE (°C/°F)

Guide to switching temperature display units between Celsius and Fahrenheit via an internal switch.

SETTING THE VERTICAL RESOLUTION FOR THE TEMPERATURE GRAPHIC DISPLAY

Procedure to adjust the upper and lower range limits for the temperature graph on the LCD.

SETTING THE VERTICAL RESOLUTION FOR THE RH GRAPHIC DISPLAY

Procedure to adjust the upper and lower range limits for the RH graph on the LCD.

SETTING THE RECORDING SAMPLE RATE

Instructions on how to set the interval at which the device records measurements.

SETTING THE TEMPERATURE ALARM LIMITS

Guide to configuring high and low alarm thresholds for temperature readings.

SETTING THE RH ALARM LIMITS

Guide to configuring high and low alarm thresholds for relative humidity readings.

Display Modes

STANDARD VIEW

Description of the default display state and how to return to it after other modes.

CURSOR

Explanation of the cursor's function for navigating and viewing data points on the graphs.

MAX-MIN DISPLAYS

ALARM DISPLAYS

USING THE CLOCK TO SORT THROUGH STORED READINGS

DEW POINT DISPLAY

SAMPLE RATE DISPLAY

Factory Default Settings

Alarm Conditions and the Alarm History

Battery Replacement

Instructions for replacing the device's batteries, including a note on battery life indicator.

Disposal

Legal obligations and methods for disposing of used batteries and the device itself.

Specifications

Two-year Warranty

Calibration and Repair Services

Contact Customer Support