Extech Instruments RH520B User manual

USER MANUAL
Paperless Humidity/Temperature Chart Recorder
Model RH520B
Additional User Manual Translations available at www.extech.com

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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.

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RH520B Description
1. Remote sensor
2. Sensor cable
3. LCD Display
4. Swivel keypad / table-top
stand
5. PC interface jack
6. Universal alarm module jack
7. AC adaptor jack
8. DATA RESET button (clears recorded measurement data and alarm history)
9. Temperature units select switch (C or F)
10. PROGRAMMING RESET button (clears programming changes but retains measurement
data and alarm history)
11. Display CONTRAST adjust
12. Sensor cable storage area
13. ‘AA’ 1.5V batteries
14. Sensor cable run
15. Wall mount holes
1
2
3 4
5
6
7

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DISPLAY DESCRIPTION
1. Temperature measurement graph
2. Internal memory usage meter
3. Vertical axis scale limits
4. Cursor / Alarm indicators
5. Push-button lock-out status indicator
6. Time display
7. Relative Humidity (RH) measurement graph
8. Date display
9. Function indicators
10. Numerical temperature reading display
11. Numerical RH reading display
12. Battery status indicator
2
3
4
3
5
6 7 8
9
9
10
11
9
12
MAX
MIN
ALARM
MAX
MIN
SET
DEW POINT

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PUSH-BUTTON DESCRIPTION
VIEW Return the LCD to the Standard View
Escape from any setting function without storing value changes
Scrolls highest and lowest (MAX/MIN) readings when in Standard View
ALARM Display or Set alarm values
TIME Display a reading stored at specific Time and Date
Set and Display the recording Sampling Rate
Set the Time and Date
SET Used in combination with other buttons to set new parameter values
Stores new parameter values and returns to the Standard View
TEMP Used in combination with other buttons to set the vertical graph range
Used in combination with other buttons to set temperature alarm values
Used in combination with the RH button to display Dew Point
RH Used in combination with other buttons to set the vertical graph range
Used in combination with other buttons to set RH alarm values
Used in combination with the TEMP button to display Dew Point
Right, left, down, and up arrow buttons for scrolling data and navigating the
display

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KEYPAD QUICK REFERENCE (ALSO SHOWN ON REAR OF THE RH520B HOUSING)
Key-press
Function
Second / Alternate Keystrokes
VIEW
Selects view mode
VIEW modes: Normal, TEMPmax,
RHmax, TEMPmin, RHmin
SET
Saves new settings
VIEW to cancel, exit mode
ARROW KEYS
Scroll through selections
Movers cursor through stored
points
TIME
View reading at specific
time/date
Arrow keys to select, VIEW to
exit
TEMP + RH
View Dew Point temp.
VIEW to exit
ALARM
Step back through ALARM
points
ALARM selects next Alarm, VIEW
to exit
SET + TEMP +
ALARM
Enters Set TEMP Alarm mode
ALARM selects HIGH/LOW, SET to
save
SET + RH + ALARM
Enters Set RH Alarm mode
ALARM selects HIGH/LOW, SET to
save
TIME + VIEW
View Sample Rate
VIEW to exit
SET + TIME + VIEW
Enter Set Sample Rate mode
SET to save, VIEW to exit
SET + TIME
Enter Set Time/Date mode
SET to save, VIEW to exit
SET + TEMP + UP
Enter Set TEMP Vertical Scale
mode
TEMP selects upper/lower, SET to
save
SET + RH + UP
Enter Set RH Vertical Scale
mode
RH selects upper/lower, SET to
save

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Getting Started
POWER
1. The RH520B runs on battery power or AC adaptor (5VDC 1A). Battery power consists of three
(3) ‘AA’batteries. See the Battery Replacement section of this manual when
changing/installing the batteries. Note: Batteries and adaptor are supplied.
2. Plug the AC adaptor in the AC adaptor jack shown in the Description section. The batteries
will act as battery back-up in the event of an AC power failure.
3. Once the batteries are installed or the adaptor properly connected, the RH520B will begin
displaying.
4. In the unlikely event that the AC power AND the battery back-up fails, the RH520B will
require a “Programming Reset” to reset the display. Press the RESET button located inside
the battery compartment. “Reset” clears all settings. Time, Date and the logging interval
need to be entered. The measurement data and alarm history, however, will still be retained
in the non-volatile memory.
5. The 5-segment battery life indicator allows the user to track the status of the battery. When
all 5-segments are dark, the battery is fully charged. Segments switch off as the battery ages.
When the battery indicator has only one segment left the batteries must be replaced
immediately.
NOTE: Always set the Date, Time, and Sample rate immediately after batteries have been
installed or after the RESET button in the battery compartment has been pressed.
Then press the Data Reset button on the rear face of the meter for >4 seconds to
clear any recorded data.
MOUNTING THE RH520B
The RH520B can be used in the following ways:
1. Placed on a table top where the swivel keypad is employed as the table stand
2. Wall mounted using the rear mounting holes
MEASUREMENT PROBE
The probe is attached to the meter with a 1-meter cable and can be used stored in the RH520B
probe cradle or remotely. The probe cable length can be easily extended with an RJ45 cable and
a gender changer.
PUSH-BUTTON LOCK-OUT SECURITY FEATURE
The RH520B can be secured from tampering by having its push-buttons locked.
1. Press for approx. 1 second and release the UP, DOWN, LEFT, and SET arrow buttons
simultaneously to lock-out the push-buttons.
Note: The security lock-out can only be performed from the main view screen. If a scroll key
or the time button was pressed prior to setting up the lock-out, the user must scroll back to
the main screen.
2. Press for approx. 1 second and release the UP, DOWN, LEFT, and SET arrow buttons
simultaneously to restore the operation of the push-buttons

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Programming the RH520B
SETTING THE TIME AND DATE
1. From the Standard View, press the SET and TIME buttons simultaneously
2. The SET indicator will appear
3. Use the UP and DOWN arrow buttons to set the time
4. Use the LEFT and RIGHT arrow buttons to step through the minutes, hours, AM/PM/24-
Hour, day, month, and year parameters
If AM or PM is selected, the date format will be MONTH-DAY-YEAR
If 24-hour is selected, the date format will be DAY-MONTH-YEAR
5. Press SET at any time to store the new value and revert to the Standard View
6. Press VIEW at any time to return to the Standard View without storing any changes
CLEARING THE INTERNAL MEMORY
Press the RESET button (located inside the battery compartment) to clear the display and
measurement parameters (sample rate, vertical resolution), and to reset the display.
Press the DATA RESET button (located on the back of the unit) to clear all the stored readings,
the MAX/MIN values, and the Alarm history.
SELECTING THE UNIT OF MEASURE FOR TEMPERATURE (oC/oF)
The oC/oFswitch, located inside the battery compartment, is used to select the unit of measure
for temperature displays
SETTING THE VERTICAL RESOLUTION FOR THE TEMPERATURE GRAPHIC DISPLAY
1. Press the SET, TEMP, and UP arrow buttons simultaneously
2. The upper temperature range indicator will flash, and the SET icon will appear
3. Use the UP-DOWN buttons to change the upper temperature value (5° increments).
4. Press the TEMP button and the lower temperature range indicator will flash
5. Use the UP-DOWN buttons to change the lower temperature value (5° increments) Note that
the upper and lower temperature values cannot overlap, and the upper value cannot be less
than zero
6. Press the TEMP button to toggle upper and lower range values
7. Press the SET button at any time to store a value and return the instrument to the Standard
View
8. Press VIEW at any time to return to the Standard View
Important: After powering on the unit and setting the Date, Time, or Sample Rate you
MUST clear the internal data memory. If you do not clear the internal data memory
you will not get the correct Time and Date stamps (2004) with your recorded data.
Press the Data Reset button on the rear face of the meter for >4 seconds.

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SETTING THE VERTICAL RESOLUTION FOR THE RH GRAPHIC DISPLAY
1. Press the SET, RH, and UP arrow buttons simultaneously
2. The upper RH range indicator will flash, and the SET icon will appear
3. Use the UP-DOWN buttons to change the upper RH value in 10% increments
4. Press the RH button and the lower RH range indicator will flash
5. Use the UP-DOWN buttons to change the lower RH value in 10% increments
6. Note that the upper and lower RH values cannot overlap
7. Press the RH button to toggle upper and lower range values
8. Press the SET button at any time to store a value and return the instrument to the Standard
View
9. Press VIEW at any time to return to the Standard View
SETTING THE RECORDING SAMPLE RATE
The Sampling Rate is the rate at which the RH520B automatically records measurements
1. Press the SET, VIEW, and TIME arrow buttons simultaneously from the Standard View
2. The current Sample Rate (in minutes) will appear in the numerical temperature display area
3. The whole minutes area of the numeric display will flash
4. The MIN and the SET icons will switch on. All other TEMP and RH indicators and numeric
displays will switch off
5. The projected TIME and DAYS representing the moment the internal memory will be full
(based on the sample rate) is displayed in the TIME and DATE display areas.
6. Use the UP-DOWN arrow buttons to increment/decrement the rate. Use the LEFT-RIGHT
arrow buttons to step through the units of time
7. Sample rates can be set from 0.1 minutes (6 seconds) up to 199.9 minutes
8. Press the SET button at any time to save changes and return to the Standard View
9. Press VIEW at any time to return to the Standard View without saving the changes
SETTING THE TEMPERATURE ALARM LIMITS
1. Press the SET, TEMP, and ALARM buttons simultaneously from the Standard View
2. The ALARM, SET, and MAX indicators will switch on. All of the RH indicators will switch off
3. Use the UP-DOWN arrow buttons to increment/decrement the HIGH temperature alarm
limit. Use the LEFT-RIGHT arrow buttons to step through the decades
4. Press the ALARM button. The MIN (low alarm) indicator will switch on
5. Use the UP-DOWN arrow buttons to increment/decrement the LOW temperature alarm
limit. Use the LEFT-RIGHT arrow buttons to step through the decades
6. The HIGH and LOW alarm limits cannot overlap
7. Use the ALARM button to toggle between the HIGH and the LOW alarm limits
8. Press the SET button at any time to save changes and return to the Standard View

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9. Press VIEW at any time to return to the Standard View without saving the changes
SETTING THE RH ALARM LIMITS
1. Press the SET, RH, and ALARM buttons simultaneously from the Standard View
2. The ALARM, SET, and MAX indicators will switch on. All of the TEMP indicators will switch off
3. Use the UP-DOWN arrow buttons to increment/decrement the HIGH RH alarm limit. Use the
LEFT-RIGHT arrow buttons to step through the decades
4. Press the ALARM button. The MIN (low alarm) indicator will switch on
5. Use the UP-DOWN arrow buttons to increment/decrement the LOW RH alarm limit. Use the
LEFT-RIGHT arrow buttons to step through the decades
6. The HIGH and LOW alarm limits cannot overlap
7. Use the ALARM button to toggle between the HIGH and the LOW alarm limits
8. Press the SET button at any time to save changes and return to the Standard View
9. Press VIEW at any time to return to the Standard View without saving the changes