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MMP8 catalogue
Smart Moisture in Oil Probe MMP8
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Vaisala MMT330 Moisture in Oil Transmitter Series – Discontinued
The Vaisala MMT330 Series provided continuous measurement of moisture and temperature in transformer oil, lubrication oil, hydraulic fluid and other liquid hydrocarbons.
- Discontinued series; not recommended for new installations
- Legacy MMT332, MMT337 and MMT338 probe configurations
- Measures water activity, relative saturation, temperature and calculated ppm
- Graphical display, data logging and versatile analogue or digital outputs
- Used for oil-condition monitoring, dryer control and free-water risk detection
- Use Vaisala MMP8 with an Indigo transmitter for new installations
Legacy Online Moisture Measurement for Oil
The Vaisala MMT330 was designed for continuous measurement of dissolved moisture in oil. It helped operators detect water ingress, monitor oil dryers and purifiers, and assess how close the oil was to the point at which free water could form.
The series combined a fixed probe with an IP66 metal transmitter housing. Depending on the selected model, the probe could be fitted to a high-pressure process, installed through a threaded connection in a restricted space, or inserted into a pressurised pipeline.
Discontinued series: For new projects, Vaisala directs MMT330 users to the MMP8 Moisture in Oil Probe. Pair it with a compatible Indigo transmitter when a display, analogue outputs, relays, Ethernet or additional system connectivity is required.
MMT330 Model Guide
| Legacy model | Probe arrangement | Typical installation | Replacement direction |
|---|---|---|---|
| MMT332 | Small flanged probe | High-pressure processes | MMP8 with the suitable process fitting and pressure review |
| MMT337 | Small pressure-tight probe with threaded connection | Restricted spaces and fixed process connections | MMP8 after checking available space, thread and insertion depth |
| MMT338 | Adjustable-length probe | Pressurised pipelines, including installations requiring controlled insertion depth | MMP8 with the appropriate ISO or NPT fitting and, where required, ball-valve installation kit |
Legacy MMT330 Measurement Specifications
| Specification | MMT330 Series |
|---|---|
| Primary measurement | Water activity from 0 to 1 aw |
| Water-activity accuracy | ±0.02 aw from 0 to 0.9 aw; ±0.03 aw from 0.9 to 1.0 aw |
| Moisture sensor | Vaisala HUMICAP® |
| Calculated quantities | Relative saturation and water concentration in ppm for configured oils |
| Temperature | Measured by the probe; applicable range depended on the selected model and installation |
| Display | Optional graphical display with trend and measurement history views |
Legacy Outputs and Transmitter Construction
| Feature | MMT330 provision |
|---|---|
| Analogue outputs | Two standard outputs with an optional third output; current and voltage selections were available |
| Digital communication | RS-232 standard; RS-485 with Modbus RTU available as an option |
| Relays | Optional potential-free relay outputs |
| Power supply | 10 to 35 VDC or 24 VAC, with additional power-supply options depending on configuration |
| Housing | Metal transmitter enclosure, IP66; display versions were IP65 |
| Mounting | Wall, DIN rail, pole or pipeline mounting accessories were available |
| Probe cable | Fixed probe cable; lengths depended on the ordered configuration |
MMT330 and MMP8 with Indigo Comparison
| Selection point | MMT330 Series | MMP8 with Indigo |
|---|---|---|
| Product architecture | Probe permanently connected to the transmitter | Interchangeable smart probe connected to a selected Indigo transmitter |
| Moisture accuracy at +20 °C | 2 %RS specified accuracy | 1 %RS specified accuracy under stated conditions |
| Temperature accuracy at +20 °C | ±0.2 °C | ±0.2 °C |
| Probe output | Signal processing tied to the transmitter | Standalone Modbus RTU from the MMP8, or expanded outputs through Indigo |
| Probe replacement | Probe and transmitter formed one measurement assembly | MMP8 can be exchanged independently, subject to configuration and system checks |
| PC software | Legacy service interface and terminal software | Vaisala Insight for configuration, diagnostics and calibration work |
| Display and local interface | Optional keypad display | Selected through the Indigo transmitter or Indigo80 handheld |
| System connectivity | Analogue outputs and optional Modbus RTU | Modbus RTU from the probe; analogue, relay, Modbus TCP and other options depend on the Indigo model |
Choose the MMP8 and Indigo Arrangement
| Requirement | Recommended starting point | Why it fits |
|---|---|---|
| Direct digital integration | MMP8 as a standalone Modbus RTU probe | Suitable where the host system can power and communicate directly with the probe |
| Compact local transmitter | MMP8 with Indigo200 | Adds a local display and practical analogue, relay or Modbus connectivity according to model |
| Rugged single-probe installation | MMP8 with Indigo300 | Provides an industrial metal enclosure, display and configurable analogue outputs |
| Closest flagship transmitter migration | MMP8 with Indigo510 or Indigo520 | Provides robust enclosure, graphical interface and expanded plant-system connectivity |
| Portable diagnostics and spot checks | Indigo80 with MMP8 | Allows portable display, logging, diagnostics and field configuration with the same probe platform |
Typical Moisture-in-Oil Applications
| Application | Measurement purpose | Selection consideration |
|---|---|---|
| Power transformers | Track dissolved moisture and changes in insulation-oil condition | Confirm the required ppm calculation and representative oil-circulation point |
| Lubrication systems | Detect water ingress before free water threatens bearings and oil performance | Review normal oil temperature, pressure, flow and contamination exposure |
| Hydraulic systems | Monitor moisture loading that can affect fluid and component life | Select a stable pressurised measurement point with safe service access |
| Oil dryers and purifiers | Monitor drying performance and control the treatment process | Compare inlet and outlet conditions under consistent temperature and flow |
| Marine and rotating equipment | Identify ingress and trend oil condition during operation | Consider vibration, access, installation pressure and probe-removal procedure |
Water Activity, Relative Saturation and ppm
Water activity, aw, indicates how close oil is to moisture saturation at the measured temperature. A value approaching 1 aw means the oil is approaching the condition in which free water may form. Relative saturation expresses the same relationship on a 0 to 100% scale.
A ppm value estimates the mass concentration of water in the oil. This conversion depends on the solubility behaviour of the specific oil, which can change with oil type, age and additives. Where ppm is required, the correct oil-specific coefficients and calculation method should be reviewed during migration.
Planning an MMT330 Replacement
- Identify whether the installed unit is an MMT332, MMT337 or MMT338.
- Record the complete order code, probe cable length, process fitting and mounting accessories.
- Confirm the oil type, normal temperature, operating pressure, flow and required insertion depth.
- List every required output, relay, communication protocol, supply voltage and local-display function.
- Check whether existing ppm conversion coefficients must be transferred or reviewed.
- Select the standard or long MMP8 and the correct ISO or NPT process fitting.
- Choose the Indigo transmitter from the required enclosure, display, outputs and communication interfaces.
- Verify the replacement at the same stable process condition before retiring the MMT330.
Vaisala MMT330 Replacement Support in Malaysia
Seacom Process Instruments supports users of the discontinued Vaisala MMT330 Moisture in Oil Transmitter Series in Malaysia and supplies the MMP8 and Indigo platform for new continuous and portable moisture-in-oil applications.
Our team can assist with legacy model identification, probe-length and process-fitting selection, ball-valve arrangements, transmitter outputs, system integration, oil-specific ppm configuration, commissioning and calibration planning.
Replacing an MMT330? Send Seacom a photograph of the transmitter label and probe installation, together with the oil type, temperature, pressure, fitting, insertion depth, supply voltage and required outputs. We will help check the suitable MMP8 and Indigo configuration.
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The Vaisala MM70 was a portable meter for spot-checking water activity and temperature in transformer, lubrication and hydraulic oils.
- Discontinued product; not recommended for new purchases
- Legacy MI70 handheld indicator with MMP78 moisture-in-oil probe
- Water-activity measurement from 0 to 1 aw
- Temperature measurement from −40 to +100 °C
- Direct insertion through a ball valve without draining the process
- Numerical display, trend graph and portable data logging
6 other products in the same category:
The Vaisala Indigo300 is a rugged industrial transmitter for one Vaisala Indigo-compatible smart probe, providing local measurement display and up to three configurable analog outputs.
Its corrosion-resistant IP66 metal enclosure, flexible probe mounting and interchangeable probe design make Indigo300 suitable for humidity, temperature, dew point, CO2, moisture in oil and other demanding industrial measurements.
The Vaisala Indigo200 Series is the standard transmitter platform for one interchangeable Indigo-compatible smart probe, providing local display and practical automation-system connectivity.
- Indigo201 with three analog outputs and two relays
- Indigo202 with Modbus RTU and two relays
- Colour display with numerical and graphical views
- IP65 enclosure for industrial measurement applications
The Vaisala MMP8 provides continuous online measurement of dissolved moisture and temperature in transformer oil, lubrication oil, hydraulic fluid and other liquid hydrocarbons.
- Measures water activity from 0 to 1 aw, relative saturation, temperature and ppmw
- Dry-end accuracy up to ±0.01 aw or ±1%RS
- Temperature measurement from −40 to +180 °C
- Available in standard 262 mm and long 448 mm probe versions
- Adjustable insertion depth with ISO 1/2 or NPT 1/2 process fittings
- Standalone Modbus RTU or connection to Vaisala Indigo transmitters
The Vaisala Indigo500 Series provides flagship industrial measurement integration: choose Indigo510 for a simplified single-probe system or Indigo520 for full dual-probe capability.
- Indigo510: one probe and two isolated analog outputs
- Indigo520: two probes, four isolated outputs and two relays
- Ethernet web interface and Modbus TCP communication
- Rugged IP66 and NEMA 4 metal enclosure
The Vaisala MM70 was a portable meter for spot-checking water activity and temperature in transformer, lubrication and hydraulic oils.
- Discontinued product; not recommended for new purchases
- Legacy MI70 handheld indicator with MMP78 moisture-in-oil probe
- Water-activity measurement from 0 to 1 aw
- Temperature measurement from −40 to +100 °C
- Direct insertion through a ball valve without draining the process
- Numerical display, trend graph and portable data logging
Vaisala HUMICAP® MMT310 Series provides continuous online measurement of moisture and temperature in transformer, lubrication and hydraulic oils.
The compact transmitter measures water activity (aw) or relative saturation (%RS), showing how close the oil is to forming free water. Optional ppm calculation is available for mineral transformer oil and configured oil types.
- Models MMT317 and MMT318
- Water activity range: 0 to 1 aw
- Temperature range: -40 to +180°C
- Two configurable analogue outputs and RS-232C
- Up to 40 bar with MMT318 and ball-valve installation
- IP66 compact transmitter enclosure
- Traceable calibration certificates included