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Grant Instruments 2YL-RH20-4M integral temperature and humidity data logger

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The compact simple to use 2YL-RH20-4M, 2YL-RH20E-4M, 2YL-RH23-4M and 2YL-RH23E-4M Yoyo data loggers from Grant Instruments are designed to measure temperature and humidity with a 4 million readings standard memory. The sensors are covered by a rugged IP65 housing to protect them from the elements.

The 2YL-RH20E-4M and 2YL-RH23E-4M models are fitted with 100 mm probe for external fitting.

The 2YL-RH23-4M and 2YL-RH23E-4 models has three integral sensors. In addition to measuring temperature and humidity, this instrument also has the capability of measuring barometric pressure.


Standard delivery includes: 1 data logger, 1 standard battery, software YoyoView, USB cable, manual, and manufacturers declaration of conformity

Grant Instruments offers a range of Yoyo data loggers including versions for temperature, humidity, condensation, extra-low voltage, strain gauge, voltage, current, pulse, barometric pressure, as well as light and solar radiation. Please contact our sales team on 01344 459314 or if the version you require is not listed within the website.

Basic YoyoView software

The basic software, included with the logger is suitable for configuring the data logger, downloading and exporting basic data. All loggers are connected to a PC or laptop via a USB cable.

YoyoView Plus software

In addition to the functionalities of the basic software, the optional upgrade offers more complex analyses of data, charts and statistics.

  • Three scaleable Y-axes
  • Zoom function
  • Cursor readings
  • Display in spreadsheet format
  • Combination of a series of measurements in one chart
  • On-line metering
  • Statistical functions


Type 2YL-RH20-4M and 2YL-RH20E-4M integral temperature and humidity sensors

Ambient temperature range -40 to 90 °C

Measuring range -40 to + 90 °C

Accuracy ± 2 % RH and ± 0.3 °C

Internal sensor resolution 0.01 K

Memory capacity (readings) 4 million

Dimensions d x h RH20 - 50 mm x 30 mm RH20E - 50 mm x 130 mm

Sensor type RH20 - 1 x temperature, 1 x humidity RH20E - 1 x 100 mm ext. temperature, 1 x humidity steel tube

Humidity sensor (internal and external) 0 to 100 % rh / 0.01 % rh

Logging interval 1 second to 24 hr

IP rating IP65

Battery type Lithum (LITH-12)

Battery life 4 years @ 1 min. / 230 days @ 10 sec. / 25 days @ 1 sec

Type 2YL-RH23-4M and 2YL-RH23E-4M Specification similar as 2YL-RH20(E) models except with the following additional features:

Accuracy ± 1.5 % hPA / ± 0.5 % hPA

Dimensions d x h RH23 - 50 mm x 33 mm RH23E - 50 mm x 130 mm

Sensor type RH23 - built-in temperature, rh and pressure RH23E - built-in temperature and rh, 2 x ext. PT1000

Barometric pressure range & resolution 10 to 1100 hPa / 0.1 hPa

Logging interval 1 second to 24 hr or Fastmode 2 Hz

Support documents

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Grant Yoyo logger user manual.pdf Grant Yoyo logger user manual
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Grant YoyoGraph software user manual.pdf Grant YoyoGraph software user manual
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Grant Yoyo logger data sheet.pdf Grant Yoyo logger data sheet
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