PosiTector DPM Dew Point Meter INSTRUCTION MANUAL v. 2.0 Simple. Durable. Accurate.
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 The PosiTector DPM powers-up when any button is pressed.
Operation Overview Upon power-up, the following 5 parameters are displayed and updated automatically each second. RH - The relative humidity sensor is located inside the white plastic housing. The sensor may require a longer period to stabilize in the event of extreme humidity changes. Ta - The air temperature sensor is also located inside the white plastic housing. Ts - A surface temperature thermocouple is located on the tip of the silver probe.
Smart TrendTM Indicators - identify rising, falling or stable readings. The instrument compares each measurement with the average of recent values in an attempt to provide the current direction of change. Smart Trend Indicators 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.
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 Reset Gage Info Flip Display Units Language Set Clock 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.
Memory Management Memory The PosiTector DPM can record 2,500 datasets in up to 100 groups (batches) for on-screen analysis, for printing to an optional IR printer, or for downloading to a personal computer using optional PosiSoft software and USB cable. NOTE: A dataset contains 6 values: RH, Ta, Ts, Td, Delta and the date/time when they were recorded. New Batch -closes any currently opened batch and creates a new batch name using the next higher number.
Open -selects a previously created batch name to open and make current. The current batch name and number of stored datasets will be displayed. Close -stops the recording process, closes the current batch, and removes batch information from the display. Delete -removes a batch completely from memory. The name is deleted and its datasets are erased. View -lists all datasets beginning with the current or most recently used batch. First to appear is a graph of individual data points as shown in Figure 1.
Print -prints stored datasets and/or summary to the optional IR printer or to a PC’s default Windows printer via the optional USB cable and PosiSoft software. Press (-)(+) simultaneously to cancel printing. Downloading Measurements Stored in Memory Datasets stored in the instrument’s memory (in batches) can be downloaded to a computer using optional PosiSoft software and USB cable (pg. 12). Datasets are not erased from memory after downloading.
NOTE: To conserve battery life, displayed values only update at the Log Interval. The last recorded values will remain “frozen” on the display until the next interval values have been stored. Recorded datasets are stored into the currently opened batch. If no batch is open, a new batch will be created. Datasets are recorded regardless of the state of the Smart Trend Indicators (see pg. 4). To turn off Auto Log, press the button and hold until the next tick sound.
Setup Menu Setup Reset Reset restores factory settings and returns the instrument to a known, out-of-the-box condition. It is handy when you want to “start all over”. The following occurs: - all batches are closed and stored datasets are erased. - menu settings are returned to the following: Memory = OFF Alarm = ON A more thorough Reset can be performed by holding the (+) button when the instrument is powered down until the Reset symbol appears.
Available Options Magnetic Surface Temperature Kit Allows the instrument and surface temperature probe to be conveniently attached onto steel structures for hands-free recording. Ideal for unattended data logging during the work shift and overnight. Interchangeable lower unit (push to disconnect) Magnetic surface temperature probe Kit Includes: -Interchangeable lower unit with built-in air temperature/humidity sensor and a K-type connector that accepts the magnetic surface temperature probe.
This lower unit accepts other optional K-type thermocouple probes including: Hand-held Surface Temperature Probe -for spot checking hard-to-reach surfaces Self-adhering Surface Temperature Probe -sticks to solid materials including aluminum, wood, concrete, etc. Ideal for unattended monitoring. Liquid Temperature Probe -general purpose probe with stainless steel shaft PosiSoft® for Windows® analysis software Downloads stored datasets to a PC with included USB cable.
Troubleshooting When the surface temperature probe is not on a surface, Air Temperature and Surface Temperature appear to be different: Under normal conditions with the surface probe in air Ta and Ts should be within the combined tolerance of each sensor (typically 1°C). It is possible for the difference to be larger if the surface probe has recently been in contact with surfaces that are at a different temperature than air.
Changing The Batteries The battery icon displays four bars with fresh alkaline batteries installed. As the batteries weaken, the number of bars will be reduced. When the batteries become very weak the Power Warning image will display and the instrument will automatically power-down. To maintain user settings and stored measurements, the batteries must be replaced. USE ONLY “AAA” ALKALINE BATTERIES Power Warning This image appears if the memory of the instrument has become corrupt.
Returning for Service Before returning the instrument for service… 1.Install new Alkaline batteries in the proper alignment as shown within battery compartment. 2.Examine the surface temperature probe tip for dirt or damage. 3.Perform a Reset (pg. 10) If you must return the instrument for service, describe the problem fully and include measurement results, if any.
Certification All PosiTector DPM instruments ship with a Certificate of Calibration. For organizations with recertification requirements, instruments may be returned at regular intervals for calibration. DeFelsko recommends that customers establish calibration intervals based upon their own experience and work environment.
