Vaisala MM70 Handheld Moisture & Temperature Meter For Spot Checking In Oil


  • Rugged and reliable construction
  • Excellent pressure and temperature tolerance
  • Data can be logged and transferred to a PC
  • Compatible with Vaisala’s fixed oil moisture instruments
  • No reference oil needed for recalibration
  • Traceable calibration (certificate included)
  • Measurement independent of oil type, age and temperature
  • In-line process checking through ball valve, no need to drain the oil
  • Proven Vaisala HUMICAP Sensor: over 15 years in oil applications

Dpstar is a leading supplier of environmental measurement sensors for temperature, relative humidity, pressure, dew point, CO2, and other environmental condition monitoring for industrial process application and research. Since the ’90s, we earned a reputation as a trusted partner to our clients through our commitment and dedication. We are an authorized distributor and supplier of measuring sensors solutions from renowned manufacturers Vaisala. Vaisala is a global leader in environmental and industrial measurement. Building on 80 years of experience, Vaisala provides observations for a better world. Vaisala is a reliable partner for customers around the world, offering a comprehensive range of innovative observation and measurement products and services.

MM70 incorporates the latest generation of the Vaisala HUMICAP Sensor, developed for demanding moisture measurements in liquid hydrocarbons. The sensor’s excellent chemical tolerance provides accurate and reliable measurement over the measurement range. Vaisala HUMICAP Handheld Moisture Meter for Oil MM70 enables reliable detection of moisture in oil. The probe can be inserted directly into the process pipe through a ball valve without draining the oil in the system. MM70 measures moisture in oil in terms of the water activity (aw) and temperature (T). Water activity directly indicates whether there is a risk of free water formation. The measurement is independent of oil type, age and temperature.

Key Benefits

Easy In-line Process Checking

The probe can be inserted directly into the process pipe through a ball valve without draining the oil in the system. No need to drain the oil.

No reference oil needed for recalibration.

cost-effective Multi-probe Operation
Supports the use of Vaisala’s humidity, dew point, and carbon dioxide probes, making it a versatile investment applicable to several multi-parameter applications. One or two probes can be connected simultaneously.


Measurement Performance, MMP78 Probe
Water Activity
Measurement range aw 0 … 1
Accuracy (including nonlinearity, hysteresis and repeatability) when calibrated against salt solutions (ASTM E104-85):
0 … 0.9 ±0.02
0.9 … 1.0 ±0.03
Maximum achievable accuracy (including nonlinearity, hysteresis and repeatability) when calibrated against high-quality, certified humidity standards:
0 … 0.9 ±0.01
0.9 … 1.0 ±0.02
Response time (90%) at +20 °C (+68 °F) in still oil (with stainless steel filter) 10 min
Sensor Vaisala HUMICAPâ 180L2
Recommended recalibration interval 1 year
Typical long-term stability better than 0.01 aw / year
Measurement range (-40 … +100 °C) (-40 … +212 °F)
Typical accuracy at +20 °C ±0.2 °C (±0.36 °F)
Sensor Pt100 RTD Class F0.1 IEC 60751
Probe Operating Environment
Operating temperature for electronics (-40 … +60 °C) (-40 … +140 °F)
Operating pressure range max. 20 bar
Operating pressure range during installation through ball valve max. 10 bar
Oil flow range max. 1 m/s
Typical temperature dependence of electronics ±0.005 °C/°C (±0.005 °F/°F)
EMC compliance EN61326-1, Portable Equipment
Probe Mechanical Specifications
Housing classification IP65 (NEMA 4)
Probe material Stainless steel (AISI316L)
Housing material APS/PC Blend
Cable length between probe and indicator 1.9 m, 10 m extension available
Weight 506 g
MI70 Measurement Indicator
Operating Environment
Operating temperature (-10 … +40 °C) (+14 … +104 °F)
Operating humidity 0 … 100 % RH, non-condensing
Storage temperature (-40 … +70 °C) (-40 … +158 °F)
Inputs and Outputs
Max. no of probes 2
Power supply Rechargeable NiMH battery pack with
AC adapter or 4xAA size alkalines,
type IEC LR6
PC interface MI70 Link software with USB or serial
port cable
Analog Output
Scale 0…1 VDC
Output resolution 0.6 Mv
Accuracy 0.2 % full scale
Temperature dependence 0.002 %/˚C full scale
Minimum load resistor 10 kΩ to ground
Mechanical Specifications
Housing classification IP54
Housing materials ABS/PC blend
Weight 400 g
EMC compliance EN61326-1, Portable Equipment
Menu languages English, Chinese, Spanish, Russian,
French, Japanese, German, Swedish,
Display • LCD with backlight
• Graphic trend display of any
• Character height up to 16 mm
Alarm Audible alarm function
Data logging capacity 2700 real time data points
Logging interval 1 s to 12 h
Logging duration 1 min … memory full
Resolution 0.01 %RH, 0.01 °C/°F, 0.01 hPa,
0.01 aw, 10 ppm / 0.01 %CO2
Battery Operation Time
Typical charging time 4 hours
Operation Times with MMP76 and MMP78
Continuous use MMP78
Continuous use 48 h typical at +20 ˚C (68 °F)
Data logging use up to a month
Spare Parts and Accessories
Weatherproof Carrying Case MI70CASE4
Ball valve set (incl. fitting body & blanking plug) HMP228BVS
Probe cable extension, 10 m 213107SP
MI70 Link software with USB cable 219687
MI70 Link software with serial port cable MI70LINK
Analog output cable 27168ZZ
Sensor protection HM47453SP
Dew point measurement probes DMP74A/B
Relative humidity measurement probes HMP75, HMP76, HMP77
Transmitter Connection Cables
MMT162 219980SP
MMT310 DRW216050SP
MMT330 211339


Vaisala-MM70-Handheld Moisture and Temperature Meter for spot checking in oil_DpstarGroup