# Extech SDL500 Hygro-Thermometer/Datalogger # Extech SDL500 Hygro-Thermometer/Datalogger ## Key Features At A Glance - Measures relative humidity (5% to 95%), temperature (32 to 122°F), dew point, and wet bulb in one instrument - Datalogger date/time stamps and stores readings on an SD card in Excel format for direct transfer to a PC - Adjustable data sampling rate from 1 to 3600 seconds for flexible logging intervals - Stores 99 readings manually and up to 20M readings via SD card (using 2G SD card) - Type K/J Thermocouple input extends temperature measurement to -148 to 2372°F (Type K) and -148 to 2192°F (Type J) - Large backlit dual LCD display with Record/Recall MIN/MAX, Data Hold, and Auto power off with disable function - Ships with 6 x AA batteries, SD card, carrying case, and Humidity/Temperature probe The Extech SDL500 is a Hygro-Thermometer/Datalogger that combines four environmental measurements — relative humidity, temperature, dew point, and wet bulb — in a single handheld instrument with integrated SD card data logging. Readings are date/time stamped and stored directly on the SD card in Excel format, which allows the logged data to be moved to a PC for analysis without intermediate software conversion. Applications listed for the SDL500 center on accurately measuring temperature and humidity in environmentally sensitive areas. The instrument's combination of continuous logging, adjustable sample rate, and the ability to record both ambient conditions and high-temperature thermocouple measurements makes it suited to monitoring scenarios where conditions need to be documented over time in one location or across a series of measurement points. ValueTronics stocks and ships the Extech SDL500 from a 20,000 square-foot secure warehouse at 1675 Cambridge Drive in Elgin, Illinois, where every new unit is handled, inventoried, and prepared for shipment in-house rather than drop-shipped from a third party. This direct stewardship of the inventory — the same building that holds it tests, documents, and ships it — is what separates a specialist test-and-measurement supplier from a pass-through broker, and it is why technical buyers who need a Hygro-Thermometer/Datalogger configured correctly the first time work with ValueTronics rather than searching marketplace listings. ## Brand Heritage Extech Instruments became part of FLIR Systems in 2007, and FLIR Systems in turn was acquired by Teledyne Technologies in 2021, becoming Teledyne FLIR. The Extech product line, including the SDL Series dataloggers, continues to be sold under the Extech brand within the Teledyne FLIR portfolio. ## Compare Other Models in This Series The SDL Series from Extech is a family of SD-card data loggers built around a common logging architecture: readings are date/time stamped and written directly to a removable SD card in Excel format, with adjustable sampling intervals and a backlit dual LCD display. Within the family, individual models are differentiated by the physical parameter being measured — the SDL500 covered here is configured for relative humidity, temperature, dew point, and wet bulb, with an added Type K/J thermocouple input for extended temperature measurement. Because the SDL Series shares its logging, storage, and PC-transfer workflow across models, customers standardizing on the SD-card-to-Excel approach across multiple measurement parameters often find it efficient to deploy several SDL units alongside each other rather than mixing logger families. Each new SDL500 listed below is its own dedicated product page with condition-matched pricing and inventory. Confirm the specific model and accessory configuration on the product page that matches your application before placing an order. The SDL500 specifically combines four measurement outputs — RH, temperature, dew point, and wet bulb — in one handheld unit, with the addition of a Type K/J thermocouple input that extends usable temperature range from the ambient 32 to 122°F window up to 2372°F. Within the SDL Series, this combination is what positions the SDL500 for users who need both environmental monitoring and the ability to log a separate high-temperature point with the same instrument. Models within the SDL Series differ primarily by which physical parameters they measure and log. The SDL500 covers humidity, temperature, dew point, wet bulb, and thermocouple temperature; other SDL Series instruments are built around different sensor sets but share the same SD-card logging, Excel-format storage, and PC transfer workflow. When evaluating across the SDL Series, the key comparison points are the primary measurement parameters of each model, the resolution and accuracy at the ranges relevant to your application, and the accessory ecosystem (probes, AC adaptors, NIST calibration option) listed for each unit. Refer to the comparison table below for the specifications most relevant to that selection. Model Measurement Type Range Resolution **SDL500** Humidity / Temperature / Dew Point / Wet Bulb / Type K / Type J 5 to 95% RH; 32 to 122°F (0 to 50°C); Type K -148 to 2372°F; Type J -148 to 2192°F 0.1% / 0.1° SDL500-NIST Humidity / Temperature / Dew Point / Wet Bulb / Type K / Type J 5 to 95% RH; 32 to 122°F (0 to 50°C); Type K -148 to 2372°F; Type J -148 to 2192°F 0.1% / 0.1° Additional differences in specifications beyond the few shown above are not listed here — see each model's full specifications below. ## Accessories Supplied - 6 x AA batteries - SD card - Carrying case - Humidity/Temperature probe ## Product Core & Specifications Specifications Range Resolution Basic Accuracy Humidity 5% to 95% 0.1% ±3% Temperature 32 to 122°F (0 to 50°C) 0.1° ±1.8°F (±1°C) Dew Point \-13.5 to 120.1°F (-25.3 to 48.9°C) 0.1° calculated Wet Bulb \-6.9 to 122°F (-21.6 to 50°C) 0.1° calculated Type K Temperature \-148 to 2372°F (-100 to 1300°C) 0.1° ±(0.4% + 1.8°F/1°C) Type J Temperature \-148 to 2192°F (-100 to 1200°C) 0.1° ±(0.4% + 1.8°F/1°C) Memory 20M data records using 2G SD card Dimensions 7.2 x 2.9 x 1.9" (182 x 73 x 47.5mm) Weight 23.1oz (655g) **Important:** Memory specification: 20M data records using 2G SD card.**Important:** Thermocouple probes (Type K and Type J) are not included with the standard SDL500 and must be ordered separately for high-temperature measurements via the Type K/J thermocouple input.**Important:** AC adaptors (153117 or UA100-240) are not included with the standard SDL500; the unit ships with 6 x AA batteries. Order an AC adaptor separately if line-powered operation is required.Recommended pairing: for high-temperature measurements above the SDL500's ambient sensor range, add the TP870 Type K bead wire probe (-40 to 482°F / -40 to 250°C) or the TP400 Type K clamp probe (-4 to 450°F / -20 to 232°C) named in the datasheet's accessory list. **Please review the Manufacturer's Data Sheet to verify published specifications. Feedback on this webpage is always welcome — please reach out to your Test Architect at any time for questions or concerns. Thank you, we truly appreciate you being our customer.** ## Details - **Price:** 489.0 USD - **Vendor:** Extech - **Type:** Data Log - **Tags:** Extech, Manufacturers, Meters & DAQ, Other, product_manual_group_2, Product_new ## Variants | Variant | Price | Available | |---------|-------|-----------| | Default Title | 489.00 USD | In stock | ## Images - SDL500 Extech Meter --- > Source: [ValueTronics](https://valuetronics.com/products/sdl500-extech-meter-new) > Updated: 2026-05-30