Product
Specications
& Features
Operating
Information &
Display Symbols
Charts &
Accessories,
Calibration
Instrument
Anatomy
Getting
Started/
Installation
Keypad
Operation
Dip Switch
Setup &
Warranty
Troubleshooting
Factory Service
& Returns
DICKSON
Charts (for current pricing go to www.dicksonweb.com or call 1-800-323-2448)
Range 24 Hour Chart 7 Day Chart 31 Day Chart
-20 to +120°F C415 C417 C480
+40 to +110°F C476 C477 C481
-20 to +50°C C472 C473 C482
+5 to +40°C C478 C479 C483
Accessories (for current pricing go to www.dicksonweb.com or call 1-800-323-2448)
Description Order #
NIST Traceable Calibration 3-pt. (new unit) N300
A2LA Accredited Calibration 3-pt. (new unit) N400
RH Calibration Kit (33% and 75%) A834
Pens (3 red/3 blue) P246
10’ Probe Extension Cable A860
50’ Probe Extension Cable A865
100’ Probe Extension Cable A866
Carrying Case A709
Probe Dust Filter (see note)* A867
*to protect probe & increase life - please use dust lter in dusty environments or where RH exceeds 70%. Probe dust lter will slow down
response time.
Calibration
Your instrument was carefully tested and calibrated
before being shipped from the factory. For greatest
accuracy, we recommend factory re-calibration every
6-12 months. Call customer service at (630) 543-
3747. If you wish to do calibration yourself, follow
these procedures. Factory supplied calibration salt
capsules or electronic instruments recently calibrated
at a certied lab are recommended. Sling psychrom-
eters and instruments using mechanical sensing ele-
ments (human hair, wood elements, bimetals, etc.)
should not be used. NOTE: The unit does not have to
be recalibrated if you used a longer probe cord.
Calibrate Humidity/Dew Point (using a
controlled chamber)
1. Turn the unit on and use dip switch #5 to select
humidity or dew point (RH=#5 off, Dew
Point=#5 on). Use dip switch #3 to select °F or
°C (°F=#3 off, °C=#3 on).
2. To activate the calibration mode, turn the unit
off. Now press the “On/Off” key and the up
arrow key at the same time. The “UC” symbol
will appear in the display to indicate you are in
“User Calibration” mode.
3. Place the probe of the unit along with your
precision relative humidity/dew point instrument
(RH/Dew Point standards) into a controlled
environment chamber and allow 15 minutes for
the unit to stabilize. For best results, calibrate
the unit at levels typically monitored during
normal operation.
4. Match the THDx reading with your precision
RH/Dew Point instrument. To raise the RH/Dew
Point reading, press the up arrow key. To lower
the RH/Dew Point press the down arrow key.
5. When calibrating is complete, simply press the
“On/Off” key to save calibration setting.
Calibrating in an open room, without the use of a
salt capsule or a chamber, is not recommended as
humidity can vary greatly within a very small area.
Calibrate Temperature
1. Press the “On/Off” key and the up arrow
simultaneously to enter the “User Calibration”
mode. Use dip switch #3 to select °F or °C.
(°F=#3 off, °C=#3 on). The display should read
“UC” in the upper right hand corner of the
display.
2. Place the THDx probe, along with your precision
temperature instrument (your temperature
standard) into a controlled environmental
chamber allowing both instruments to completely
stabilize for approximately 1 hour.
3. Match the THDx reading with your precision
temperature instrument.
4. To raise temperature reading, press the “Alarm
Set” key. To lower the temperature reading press
the “Alarm On/Off” key. Each key press adjusts
the reading by 1°F.
5. When calibration is complete, simply press the
“On/Off” key to save calibrated changes.
Calibration is stored in memory even after you turn
the unit off. User calibration information will not be
lost of AC power fails.
