Checkline PT-DPM User Manual

PosiTector DPM

Dew Point Meter

INSTRUCTION MANUAL v. 2.0

Simple. Durable. Accurate.

Introduction

Introduction

The Dew Point Meter is a hand-held, electronic
instrument that measures, calculates and records
climatic parameters, quickly and accurately.

Measured parameters are:

RH - Relative Humidity
Ta - Air Temperature
Ts - Surface Temperature

Td - Dew Point Temperature

- Surface minus Dew Point
Temperature

Surface
Temperature
Sensor

Air temperature
and humidity
sensor

Power-up / Power-down

Power-up / Power-down

The PosiTector DPM powers-up when any button is
pressed. To preserve battery life, the instrument
powers-down after approximately 3 minutes of no
button activity. To power-down immediately, hold
both (-)(+) buttons for 5 seconds. Settings are
retained during power-down.

2

Operation Overview

Operation Overview

Upon power-up, the following 5 parameters are
displayed and updated automatically each second.

RH - The relative humidity

the white plastic housing. The sensor may require a
longer period to stabilize in the event of extreme
humidity changes.

Ta - The air temperature

inside the white plastic housing.

sensor is located inside

sensor is also located

Ts - A surface temperature thermocouple is located

on the tip of the silver probe. It is spring loaded and
designed to quickly self-align on a surface. Press it
against a surface and allow a few seconds for the
value to stabilize. Do not drag the sensor over the
surface. Wet the surface for a faster response.

NOTE:

For surface temperature measurement over
a long period of time, consider using the optional
Magnetic Surface Temperature kit (pg. 11).

Td - The dew point temperature is a function of air

temperature and relative humidity (see ISO 8502-4
Annex A). It is the temperature to which a volume of
air must be cooled in order to reach saturation.

- The delta value is the surface minus dew poin

temperature (Ts - Td). This value is important in
judging the risk of condensation, or dew, forming on
a surface. For example, ISO 8502-4 recommends
that, unless otherwise agreed, the temperature of a
steel surface generally should be at least 3°C (5°F)
above the dew point when paints are applied.

NOTE:

before the above climatic parameters stabilize. This
is most noticeable when the instrument is relocated
from one extreme environment to another (i.e. from
a warm location to a cold location). A period of up to
30 minutes should provide adequate time for
stabilization.

The instrument may require a period of time

t

3

Smart Trend

or stable readings. The instrument compares each
measurement with the average of recent values in
an attempt to provide the current direction of change.

While the absence of an arrow does not necessarily
signify stability, it can be taken to mean that particu­lar parameter is undergoing little or no change. Slow
changes in a parameter could therefore occur
without being noted by an indicator arrow. When
instructed to manually store a dataset into memory
(pg. 6), the instrument will wait for these Smart Trend
Indicators to disappear before recording all values to
memory.

Button Shortcuts:

(-) Button: causes the display to rotate 180°. Ideal

for right-side-up viewing when sensors are pointing
away from you. Press (-) again to restore display
position.

(+) Button: freezes the display. The instrument will
measure one more time, then hold all values and
display the hold icon . Press (+) again to unfreeze
the display. This feature does not work while in
Memory Mode.

TM

Indicators - identify rising, falling

Smart Trend
Indicators

Button: accesses the instrument menu (pg. 5).

Within the menu, the button is used to select an
option.

4

Menu Operation

Menu Operation

Instrument functions are menu controlled. To access
the Menu, turn the instrument on, then press the
button.

Memory
Auto Log
Alarm

9

Setup

Current selection is displayed
with darkened background

To navigate, press (-) to scroll DOWN, (+) to scroll UP
and to SELECT. Press both (-)(+) buttons at any
time to exit any menu or select Exit from the Menu.

List boxes have a down arrow on the right-hand side.
Use the (-) and (+) buttons until your desired choice
appears, then press to select this choice and
move focus onto the next item.

a “tick” indicates this square

box has been selected

“Radio” buttons. Only one
can be selected at a time.

“Focus” is currently at this
unselected (empty) Radio button

Reset

Gage Info

Flip Display

Units
Language

Set Clock

“List“ box

5