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Teledesign TS4000 900MHz UHF/VHF

True cloud-based sensor configuration, logging, reporting and data analysis all-in-one.


Shark (RS232/RS485 Bluetooth Serial Adapter)


A cloud-based interface to configure hardware, visualize data, analyze measurements, manage alarms, calculations, and set up data routing.

MEASUREMENTS TO MIND (M2M) is a growing suite of Stevens products that embraces cloud-computing with an all-inclusive vision of shortening the communication path from the sensors to data on-line. That is, what the sensors MEASURE the MIND sees.

The product finder lets you explore our catalog visually and filter products by type of monitoring, manufacturer, and more.


SOLO (smart SDI-12 power manager)
JL-2 (solar charge controller)
Power Supplies
Solar Panels

Smart SDI-12 power manager that also provides remote power cycling.

The product finder lets you explore our catalog visually and filter products by type of monitoring, manufacturer, and more.

The product finder lets you explore our catalog visually and filter products by type of monitoring, manufacturer, and more.

Vaisala Humicap® HMP155

Humidity and temperature sensor

Part # 51070

vaisala hmp155

The Vaisala Humicap HMP155 humidity and temperature probe provides reliable humidity and temperature measurement. The HMP155 has a new generation Vaisala Humicap®180R sensor that has excellent stability and withstands harsh environments. The probe structure is solid and the sensor is protected with a sintered teflon filter, which gives maximum protection against liquid water, dust, and dirt.

Measuring humidity reliably is challenging in environments where humidity is near saturation. Measurements may be corrupted by fog, mist, rain, and heavy dew. A wet probe may not give an accurate measurement in the ambient air.

This is an environment to which Vaisala has designed a patented, warmed probe for reliable measuring. As the sensor head is warmed continuously, the humidity level inside it stays below the ambient level. Thus, it also reduces the risk of condensation forming on the probe.

The HMP155 is especially designed for use in meteorological applications, such as synoptic and hydrological weather stations, aviation, and road weather.

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What's the Easiest and Quickest Way to Start Collecting Data and Access it Anywhere?

The Answer's in the Cloud.

eTracker is a cellular modem and "virtual" cloud-based data logger in one (meaning you don't need to install a separate data logger). Simply connect your sensor and a power source to eTracker and you're done. Configure (or reconfigure) anytime from any Internet-connected device, and use Stevens-Connect to retrieve your data, or forward it to your favorite software system.

Technical Specifications

Relative Humidity

Measurement range

0 ... 100 %RH

Accuracy (incl. non-linearity, hysteresis and repeatability) at
+15 to +25 °C (+59 to +77 °F)

-20 to+40 °C (-4 to 104 °F)
-40 to -20 °C (-40 to -4 °F)
+40 to +60 °C (+104 to +140 °F)
-60 to -40 °C (-76 to -40 °F)
Factory calibration
uncertainty (+20 °C /+68 °F)

±1 %RH (0 ... 90 %RH)
±1.7 %RH (90 ... 100 %RH)
±(1.0 + 0.008 x reading) %RH
±(1.2 + 0.012 x reading) %RH
±(1.2 + 0.012 x reading) %RH
±(1.4 + 0.032 x reading) %RH
±0.6 %RH (0 to 40 %RH)
±1.0 %RH (40 ... 97 %RH)

Response time at +20 °C in still air with a sintered PTFE filter

20 s
60 s


Measurement range

-80 °C to +60 °C (-112 °F to +140 °F)

Accuracy with voltage output at
-80 to +20 °C
+20 to +60 °C
passive (resistive) output according to IEC 751 1/3 Class B
RS485 output
-80 to +20 °C
+20 to +60 °C

±(0.226 - 0.0028 x temperature) °C
±(0.055 + 0.0057 x temperature) °C
±(0.1 + 0.00167 x |temperature|)°C

±(0.176 - 0.0028 x temperature) °C
±(0.07 + 0.0025 x temperature) °C

Temperature sensor

Pt100 RTD Class F0.1 IEC 60751

Response time with additional temperature probe in 3 m/s air flow

<20 s
<35 s


Operating temperature range

-80 °C to +60 °C (-112 °F to +140 °F)

Storage temperature range

-80 °C to +60 °C (-112 °F to +140 °F)


8-pin male M12 connector

Connection cables

3.5, 10, and 30 m

Cable material


Wire size


Service cables

USB connection cable
MI70 connection cable

Additional T probe cable length

2 m

Housing material


Housing classification


Sensor protection

sintered PTFE
optional membrane filter

Weight (probe)

86 g


267 mm L x 40 mm Ø

Electromagnetic compatibility

Complies with the EMC standard EN61326-1, Electrical equipment for measurement control and laboratory use - EMC requirement for use in industrial locations

Inputs and outputs

Operating voltage

7 to 28 VDC
Note: minimum operating voltage 12 V with 0 to 5 V output and 16 V with 0 to 10 V output, probe heating, chemical purge or XHEAT.


voltage output (0 - 1 V, 0 - 5 V, 0 - 10 V)

resistive Pt100 (4-wire connection)

Average current consumption (+15 VDC, load 100 kOhm)
0 to 1 V output

0 to 10 V output


during chemical purge
with warmed probe

<3 mA
+0.5 mA
<4 mA
max 110 mA
max. 150 mA

Settling time at power-up
voltage output

2 s