Dwyer Instruments 485-2 Specification And Operating Instructions

Operating Instructions & Specifications

Introduction

The Model 485 Digital Hygrometer is a versatile, hand-held,
battery-operated humidity and air temperature measurement
system. The instrument will directly measure temperature, in
either °C or °F, and percent relative humidity. The 485 will also
calculate the dew point temperature and the wet bulb tempera-
ture based on the relative humidity and temperature readings.
MIN and MAX functions are provided to save minimum and
maximum temperature and relative humidity readings. The
reading may also be frozen using the HOLD function. In addi-
tion, a memory function is provided which will hold up to 25
humidity and temperature samples.

Battery Installation

The unit is shipped with a separate 9 Volt alkaline battery
which must be installed before operation. Remove the two
screws holding the bottom endcap in place and remove it.
Connect the battery to the enclosed battery clip, observing cor-
rect polarity. Be careful not to trap the wires between the case
or foam pad which retains the battery. This could make it diffi-
cult to install the battery or remove it later for replacement. Be
sure the rubber gasket is properly seated in the gasket channel
and replace the endcap. Note that the endcap will only fit one
way because the holes are slightly off-center. Place the "Z"
shaped wrist strap clip in one of the screw recesses and replace
the screws. Do not overtighten. Attach the wrist strap to the
clip.
When battery replacement becomes necessary, use only 9
Volt alkaline type batteries such as a Duracell® MN1604, or
Eveready® 522 or equivalent. Zinc-carbon types, often labeled
Heavy-Duty are not recommended because of their shorter life
DWYER INSTRUMENTS, INC.
P.O. BOX 373 • MICHIGAN CITY, INDIANA 46361, U.S.A.
Model 485-2 Digital Hygrometer
Specifications and Operating Instructions

Specifications

Relative Humidity Measurement
Temperature Measurement
Ambient Temperature Operating Range
Storage Temperature Limits
Power Source
and an increased potential for leakage. Alkaline batteries are a
better value because they last typically up to three times longer
in this device.

On-Off Operation

The on-off control is a toggle function. Press the ON/OFF key
once to turn the unit on; again to turn it off. If the hygrometer is
left on with no activity for approximately 22 minutes, the unit
will turn itself off to conserve the battery. Each time a key is
pressed, the timeout will be reset to 22 minutes.
An extended timeout function is provided for situations
where the 22 minute timeout is not long enough. With the unit
off, press the ON/OFF key and the DP/WB/STORE key simulta-
neously during power on and release them together. The
"ALARM 2" annunciator will be illuminated. The power timeout
will now be approximately 23 minutes from the time the unit is
turned on. This function is also useful for min/max sampling.
Turn the unit on in the extended timeout mode then clear the
MIN/MAX memory and place the unit in the desired location. It
will record the minimum and maximum temperature and humid-
ity measured during the sample time.

Display Backlight

The Model 485 includes a display backlight to allow use in
the dark or in poor lighting conditions. The unit must be off
before this feature can be activated. Next, press and hold the
ON/OFF key down. After about 1 second the backlight will
come on and remain lighted for approximately 2 minutes after
which it will turn itself off to conserve the battery.

Selecting Temperature Units

The temperature readings may be displayed in either °F or
°C. The currently selected units will be indicated on the display.
Phone: 219/879-8000
Fax: 219/872-9057
Lit-By Fax: 888/891-4963
Range: 0-100%
Accuracy: ±2%
Resolution: 0.1%
Sensor Operating Temperature:
-22° to 185°F ( -30° to 85°C)
Range: -22° to 185°F (-30° to 85°C)
Accuracy: ±1°F (0.5°C)
Resolution: 0.1°
32° to 104°F (0° to 40°C)
-40° to 176°F (-40° to 80°C)
9 Volt Alkaline Battery
www.dwyer-inst.com
e-mail: info@dwyer-inst.com
Bulletin E-85-A