Vaisala MMP8 Datasheet

MMP8 Moisture in Oil Probe

Features

• Continuous online measurement
of moisture in oil and temperature

• Temperature measurement range

−40 … +180 °C (−40 … +356 °F)

• Measurement accuracy up to
±0.01 aw (±1 %RS)

• Incorporates the proven Vaisala
HUMICAPâ sensor, used for over
20 years in oil applications

• Modbusâ RTU over RS-485

• Traceable calibration certificate:
6 points for humidity, 1 point for
temperature

• Compatible with Indigo series
transmitters and Insight PC
software

â

Vaisala HUMICAP

Moisture in Oil Probe MMP8 enables fast and reliable measurement
of moisture in oil. It uses the proven Vaisala HUMICAPâ sensor, which was developed
for demanding dissolved moisture measurements in transformer and lubrication oils,
hydraulic fluids, and other liquids.

Reliable Vaisala HUMICAP

â

technology

MMP8 incorporates the latest-generation
Vaisala HUMICAPâ 180L2 sensor, which is
the result of over 20 years of field
experience. It was developed for
demanding moisture measurement in
transformer and lubrication oils and
other liquids.

The sensor's excellent chemical tolerance
provides accurate and reliable
measurement over a wide measurement
range. The HUMICAPâ 180L2 sensor has
excellent sensitivity in the dry end of the
range, which is typically needed in
transformer applications.

Measure the margin to water
saturation

MMP8 measures dissolved moisture in oil
in terms of the water activity (aw),
relative saturation (%RS), and
temperature (T). Water activity or

relative saturation indicate directly
whether there is a risk of free water
formation. This data is relevant in
lubrication oil applications where
detecting water ingress and preventing
free water formation is crucial. The
measurement is independent of oil type
and age.

MMP8 can also output ppm, the average
mass concentration of water in oil.
Vaisala has this conversion readily
available for specific oils, including
mineral transformer oil. This allows
continuous measurement of ppm
concentration in power transformer
condition monitoring.

For other oils, the oil-specific conversion
coecients can be calculated if the
water solubility of the oil is known and
the solubility characteristic remains
constant.

Easy installation

When installed with the ball valve kit, the
MMP8 is ideal for installation into
processes where the probe needs to be
installed or removed while the process is
running. Probe installation depth is
adjustable. Pressure fitting options are
ISO 1/2" and NPT 1/2". MMP8 is delivered
with a manual pressing handle that
allows the probe to be pushed against
process pressure.

DNV GL type approval
certificate no. TAA00002YT

Technical data

000.1

±0.01

0.2

±0.02

0.3

±0.03

0.4 0.5 0.6 0.7 0.8

0.9

1.0

±0.04

a

w

reading accuracy

aw reference

T = 0 … +80 °C

T = −40 … 0 °C, +80 ... +180 °C

136 [5.35]

Probe cable 2 m [6.56 ft]

Ø 25

[0.98]

M12/5

Ø 5

[0.2]

262 [10.32]

224 [8.82]

35 ... 179 [1.37 ... 7.05]

35 [1.37]

Ø 13.5

[0.53]

Fitting body
ISO1/2” or NPT1/2”

Ø 12

[0.47]

mm
[in]

Measurement performance

Water activity

Measurement range 0 … 1 a

T90 response time

1)

Sensor

2)

Accuracy

w

10 min

HUMICAPâ 180L2

±0.01 aw (±1 %RS)

Temperature

Measurement range −40 … +180 °C (−40 … +356 °F)

Accuracy at +20 °C (+68 °F) ±0.2 °C (0.36 °F)

1) At +20 °C (+68 °F) in still oil.

2) In range 0 … 0.5 aw, including non-linearity, hysteresis, and repeatability. See accuracy graph below.

MMP8 Aw measurement accuracy

Operating environment

Operating temperature of probe head −40 … +180 °C (−40 … +356 °F)

Operating temperature of probe body −40 … +80 °C (−40 … +176 °F)

Storage temperature range −40 … +80 °C (−40 … +176 °F)

Operating pressure range 0 … 40 bar (0 … 580 psia)

Installation pressure Up to 10 bar (145 psia)

IP rating of probe body IP66

Ball valve

Operating temperature Up to +120 °C (+248 °F)

Operating pressure Up to 40 bar (0 … 580 psia)

Compliance

EU directives EMC Directive (2014/30/EU)

RoHS Directive (2011/65/EU)

EMC compatibility EN 61326‑1, industrial environment

Type approvals DNV GL certificate no. TAA00002YT

Compliance marks CE, China RoHS, RCM, WEEE

Mechanical specifications

Connector M12 5-pin A-coded male

Weight 510 g (18.0 oz)

Filter options Stainless steel grid standard filter

Stainless steel grid filter for high flow
rates (> 1 m/s)

Probe cable length 2 m (6.56 ft)

Adjustable installation depth 35 … 179 mm (1.37 … 7.05 in)

Materials

Probe AISI 316L

Probe body AISI 316L

Cable jacket FEP

MMP8 dimensions

Inputs and outputs

Operating voltage 15 … 30 V DC

Current consumption 10 mA typical

Digital output RS-485, non-isolated

Protocols Modbus RTU

Output parameters Relative saturation (%RS)

www.vaisala.com

Accessories

Ball valve ISO 1/2" with welding joint BALLVALVE-1

Ball valve ISO 1/2" – ISO 3/4" with
thread joint

1)

Temperature (°C)

Indigo USB adapter

1) Vaisala Insight software for Windows available at www.vaisala.com/insight.

Water activity
Water mass fraction (ppmw)

Published by Vaisala | B211795EN-B © Vaisala 2021

All rights reserved. Any logos and/or product names are trademarks of Vaisala or its individual partners.
Any reproduction, transfer, distribution or storage of information contained in this document is strictly
prohibited. All specifications — technical included — are subject to change without notice.

BALLVALVE-2

USB2