2YL-M91-4M Multi Input Logger (Internal Temp./Rel. Humidity, Pressure + Light)


Grant Instruments


Datalogger with integrated sensors for humidity, temperature, light and barometric pressure as well as two sockets for external probes and signals. 4 Million readings, operating range -40 to +90ºC, IP65 rated.
Supplied with YoyoLog View software, USB lead and long life battery.

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Environment of Use Indoor/Outdoor
Type of Logger Miniature
Measured Parameters Temp./Rel. Humidity, Pressure, Light.
Number of Channels 6 channels
ADC Bits 20 bit
Precision -40 to +90ºC
With Display No
IP Classification IP65
Communications USB
Battery Life 4 years
Memory Capacity 4 million readings

• Rugged IP65 housing
• Status LED: - Indicates Alarm - Low Battery Warning
• Accepts 2 x External Probes
• Multi function logger
• Intergrated Barometric Pressure, Temperature and Humidity sensors

Software YoyoView (YY-100)

The basic software (YY-100), included with the logger, is suitable for configuring the logger, downloading basic data and exporting data. The yoyo logger can be connected to laptop or PC via a USB port.

It is also available for download here:

Dimensions (d x h) 50 x 33mm
Ambient temperature range -40 to +90ºC
Measuring range -40 to +90ºC
Internal sensor resolution 0.01K
Memory capacity (readings) 4 million
Active start
Sensor type Internal Temperature/Humidity, Pressure + Light

Humidity Sensor
(Internal and External)

0 to 100% RH/0.01% RH

Barometric Pressure Range
+ Resolution

10 to 1100 hPa/0.1 hPa


1 second to 24 hours
IP rating 65
Battery type LITH-12

Battery life (Logging Speed)
1 minute

4 years
10 seconds 230 days
1 second 25 days
Robust, shock proof

** Higher voltage levels up to 24 Volts require the YY-CP cable.

  • Test and measurement

Uptime monitoring of harbour cranes, photovoltaic systems. Tyre manufacturing, raingauge, water supply counte

  • Weather monitoring

Monitoring outside temperature / humidity and via connected sensors also soil moisture and rainfall

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