RH BluePeg Probe

RH BluePeg probes are used with Lignomat’s RH meters or data loggers. To connect the RH probe to one of the meters or data loggers an in-between connection is needed, either the RH adapter or a RH cable.

Thermo-Hygrometer:  RH meters and data loggers function as thermo-hygrometers after the RH BluePeg Probe has been connected.  The meters indicate ambient relative humidity, temperature, dew point temperature, and grains per pound. For a short connection the handy RH adapter is available. For remote measurements cables up to 50 ft long are available. Standard length supplied is 6ft.

Concrete in-situ RH Moisture Testing:  Lignomats RH BluePeg system is designed to measure moisture in concrete complying with ASTM standard F2170. The unique system uses reusable, removable RH BluePeg probes for multiple testing. RH Probes, sleeves, cables and meters allow for a fast, simple and fail-proof test procedure.

Lignomat offers three RH meters and two data loggers:
— Ligno-Tec RH  — Ligno-DuoTec BW  — Ligno-VersaTec

— RH data logger BL2 Memo-Chip
— MC Moisture Tracker

Item Number: RH-BP

Starting at $85.00

Product Description

The RH BluePeg is a fast-reacting, accurate relative humidity and temperature probe. The RH BluePeg probe has been designed to comply with requirements of ASTM standard F2170 for in-situ concrete moisture testing.

The RH BluePeg probe has a diameter of 0.5 inches, length is 1.35 inches with 0.5 inch slots for air circulation around sensing element.

The RH probe is equipped with a 3.5mm stereo jack. The RH adapter or a RH cable is necessary to make the connection to Lignomat’s RH meters and data loggers. Adapter and cable are equipped with 3.5mm stereo plugs. The 3.5mm stereo connectors are simple, fast-to-connect and failproof. No pin arrangements have to be fitted, not on the RH meter and not on the RH probe. As soon as the RH probe is connected, the meter automatically switches to the RH mode and indicates relative humidity, ambient temperature, dew point temperature and grains per pound. The data loggers are set up to indicate RH, T, DT, GPP and EMC.

The RH BluePeg probe uses a single micro-chip humidity and temperature sensor, factory calibrated to NIST standards. A NIST certificate can be found on this web page in the Document tab. During the first year we offer to check the accuracy of the probe calibration three times at no extra cost. This is helpful for our customers, who use the RH probes for in-situ concrete testing, because ASTM regulations require a calibration check when the probes are being re-used. Click for specifications.

RH meters indicate the measured values for RH, Temp, DewT and GPP. Each RH probe has an individual probe number programmed on the micro-chip. The last 3 digits of this number are displayed on the RH meters.


When used as thermo-hygrometer, the RH BluePeg probe is connected to the RH meter with the RH adapter. If the probe needs to stick out further than 2.25″ above the top of the meter, RH depth-adapters can be added. A RH cable 6 ft long is available for remote measurements. Longer or shorter cables can be custom-cut.

When used for in-situ probe testing in concrete, the RH BluePeg probes fit into the RH sleeves and are connected with the RH concrete cable. The cable is a standard 3.5mm stereo cable with a special fitting on one end to fit into the sleeve for measurements.

More info on in-situ probe testing
– More info on Lignomat’s RH in-situ probes

RH BluePeg probes are used with:

— Ligno-Tec RH: RH only
— Ligno-DuoTec BW: RH and pinless
— Ligno-VersaTec: RH and pinless and pin 

— RH data logger BL2 Memo-Chip
— MC Moisture Tracker: RH and moisture content

The RH adapter connects RH BluePeg probes to RH meters and data loggers.
If you need a cable for remote RH measurements, click here to order the RH cable.
If you need a cable for in-situ RH concrete moisture testing, click here to order the RH concrete cable.

For more information please contact Customer Service at 1-800-227-2105.

Lignomat USA Ltd, 14345 NE Morris Crt., Portland OR 97230, USA,


Properties RH Measurements with RH BluePeg Probes
Relative Humidity Range 0% to 99.9% 
±2% for 10% to 90%
±3% for below 10% and above 90%
Resolution for entire range is 0.1%
Range 5°F to 160°F  (-15°C to 70°C)
±0.5°F for 32°F to 120°F  (±0.3°C for 0°C  to 50°C, )
±1°F for 5°F to 32°F .(±0.5°C for -15°C to 0°C, )
±1°F for 120°F to 160°F .(±0.5°C for 50°C to 70°C, )
Resolution for entire range  is 0.1°F (0.1°C)
DPT -17.8°F to 160°F (0°C to 70°C)
GPP 0-99.9
RH Probe Ø 0.5 inches (1.27cm), length 1.35 inches (3.8cm)
RH Probe
Easy-to-connect 3.5 mm stereo connectors.
RH probe comes with jack.
RH adapter and RH cables come with plugs on both ends to connect RH BluePeg probe to moisture meters or data loggers.
Calibration All RH BluePeg probes are NIST certified
Calibration Salts for 33 and 75% RH available.
During the first year Lignomat checks the calibration three times at no charge.
Warranty All moisture meters have a 2 year warranty. All accessories incl. RH BluePeg probe have a 1 year warranty and battery is excluded


For more information please contact Customer Service at 1-800-227-2105.

Lignomat USA Ltd, 14345 NE Morris Crt., Portland OR 97230, USA,