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HMT370EX catalogue
Intrinsically Safe Humidity and Temperature Transmitter Series HMT370EX
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Vaisala HMT360 Intrinsically Safe Humidity and Temperature Transmitter – Discontinued
The Vaisala HMT360 Series was an intrinsically safe transmitter platform for humidity, temperature and moisture measurement in hazardous areas. It is discontinued and replaced by the Vaisala HMT370EX with an application-specific probe.
- HMT361 wall mounting → HMP371
- HMT363 ducts and confined spaces → HMP373
- HMT364 high pressure and vacuum → HMP374
- HMT365 high temperature → HMP375
- HMT367 high humidity → HMP377
- HMT368 pressurised pipelines → HMP378
Product status: The Vaisala HMT360 Series is discontinued. For new hazardous-area installations and planned migrations, use the Vaisala HMT370EX intrinsically safe transmitter with the probe and regional certification selected for the application.
Vaisala HMT360 for Existing Hazardous-Area Installations
The Vaisala HMT360 Series provided intrinsically safe humidity and temperature measurement for potentially explosive gas and dust environments. Different probe versions supported wall mounting, confined spaces, high pressure, vacuum, high temperature, high humidity and pressurised pipelines.
Configuration-dependent versions also measured moisture in industrial oil, JET A-1 fuel and natural gas. The transmitter used two-wire 4–20 mA measurement channels through an approved intrinsic-safety interface, with service communication used for configuration and calibration.
HMT360 to HMT370EX Replacement Guide
| Legacy model | Original application | Current HMT370EX probe | Migration note |
|---|---|---|---|
| HMT361 | Wall-mounted ambient measurement | HMP371 | Fixed probe for wall or enclosure installation |
| HMT363 | Ducts, channels and confined spaces | HMP373 | Check probe cable material, insertion depth and temperature class |
| HMT364 | High-pressure processes and vacuum | HMP374 | Confirm process pressure, fitting and safe isolation arrangement |
| HMT365 | High-temperature processes | HMP375 | Check probe-head temperature against the required Ex temperature class |
| HMT367 | Continuous high humidity and demanding wet conditions | HMP377 | Review probe heating and external temperature compensation requirements |
| HMT368 | Pressurised pipelines | HMP378 | Confirm insertion depth, fitting body and ball-valve arrangement |
Explore the Vaisala HMT370EX replacement platform
Special HMT360 Moisture and Natural-Gas Versions
| Legacy configuration | Original medium or use | Current starting point | Important requirement |
|---|---|---|---|
| HMT368F / HMT360F | Moisture in industrial oil | HMT370EX with HMP378F | Confirm oil type, water-solubility coefficients, process fitting and certification |
| HMT368H / HMT360H | Moisture in JET A-1 fuel | HMT370EX with HMP378H | Confirm aviation-fuel application, installation and applicable approval |
| HMT362N | Natural gas with a flanged probe arrangement | Application review required | Do not assume a current standard probe duplicates the legacy flange and certification |
| HMT364N | High-pressure natural gas | HMT370EX with HMP374 as the technical starting point | Gas compatibility, pressure, process sealing and hazardous-area approval must be confirmed |
| HMT368N | Natural-gas pipeline installation | HMT370EX with HMP378 as the technical starting point | Confirm gas service, pipeline pressure, insertion method, fitting and certification |
Special-medium warning: a similar probe shape or pressure rating does not by itself approve a replacement for natural gas, oil or aviation fuel. The measured medium, complete Ex marking, sealing materials, pressure boundary and regional certification must be reviewed for the exact ordered configuration.
HMT360 and HMT370EX Comparison
| Comparison point | HMT360 Series | HMT370EX Series |
|---|---|---|
| Product status | Discontinued | Current replacement platform |
| Safety concept | Intrinsically safe legacy transmitter | Current intrinsically safe Ex i transmitter |
| Probe options | HMT361, HMT363, HMT364, HMT365, HMT367 and HMT368 variants | Interchangeable HMP371, HMP373, HMP374, HMP375, HMP377 and HMP378 probes |
| Special moisture versions | Oil, JET A-1 and selected natural-gas configurations | HMP378F for oil and HMP378H for JET A-1; natural gas requires application review |
| Relative-humidity range | 0 to 100 %RH | 0 to 100 %RH within model and dew-point limitations |
| Best stated RH accuracy | Up to ±1.0 %RH at +20 °C | Up to ±0.8 %RH at +23 °C |
| Temperature measurement | Probe-dependent, up to −70 to +180 °C | Probe- and certification-dependent, up to −70 to +180 °C |
| Analogue outputs | Two-wire 4–20 mA, configuration-dependent | Two configurable two-wire 4–20 mA channels |
| Probe servicing | Legacy removable-probe arrangement | Interchangeable smart probes with independent calibration |
| Ingress protection | IP65 legacy enclosure | Up to IP66 with the probe connected; configuration-dependent |
Hazardous-Area Migration Checks
Replacing an intrinsically safe transmitter requires more than matching the measured parameter. Review the complete electrical and mechanical installation before changing the device.
- Record the complete HMT360 model code, Ex marking and certification documents.
- Confirm the gas or dust zone, gas group, dust group and required equipment protection level.
- Check the required temperature class and maximum ambient and process temperatures.
- Verify the safety barrier or galvanic isolator against the HMT370EX entity parameters.
- Include field-cable capacitance, inductance and cable length in the intrinsic-safety assessment.
- Confirm whether one or two 4–20 mA measurement channels are required.
- Map the existing measurement ranges, engineering units and receiving-system scaling.
- Check probe fitting, pressure rating, insertion depth, sealing materials and removal procedure.
- Select the correct regional certificate for the country where the equipment will be installed.
Probe Temperature and Ex Temperature Class
The maximum measuring range of a probe is not automatically the permitted temperature in every hazardous-area installation. The allowed temperature depends on the probe model, cable material, gas or dust classification and required Ex temperature class.
| Example temperature class | Published upper probe-head limit for applicable configurations | Selection guidance |
|---|---|---|
| T6 | Approximately +55 °C | Use the exact limit stated in the regional safety guide and ordered configuration |
| T5 | Approximately +100 °C | Applicable probe and cable configuration must be confirmed |
| T4 | Up to approximately +135 °C for applicable remote probes | Do not use the general probe range as the certified limit |
| T3 | Up to +180 °C for applicable probe configurations | Confirm the complete Ex approval, ambient conditions and installation method |
Can an Existing HMT360 Remain in Service?
A functioning HMT360 does not need to be removed solely because the series is discontinued. Keep the transmitter label, probe model, barrier information, control drawing, wiring diagram, calibration certificates and configuration records while the installation remains in service.
For a critical hazardous-area measurement, check calibration and repair availability and plan migration before a failure creates an extended process interruption. Any service work must preserve the approved intrinsic-safety installation and be carried out by suitably competent personnel.
Vaisala HMT360 Support and HMT370EX Replacement in Malaysia
Seacom Process Instruments supports existing Vaisala HMT360 intrinsically safe transmitters in Malaysia and supplies the current HMT370EX platform for chemical production, pharmaceuticals, paint booths, powder handling, fuel storage, oil and gas processes and other hazardous areas.
Our team can assist with identifying the legacy probe, selecting the HMT370EX configuration, reviewing process fittings and pressure limits, mapping 4–20 mA outputs, coordinating safety barriers, commissioning and calibration planning.
Contact Seacom with the complete HMT360 model code, nameplate photographs, hazardous-area classification, measured medium, process temperature and pressure, existing barrier details and required outputs so we can review a suitable migration arrangement.
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The Vaisala HMT370EX provides intrinsically safe humidity and temperature measurement with HMP-series probes. The new DMP370 configuration combines the HMT370EX transmitter with a DMP37X DRYCAP® probe for low-dew-point measurement in hazardous locations.
- HMP probes for relative humidity and temperature
- DMP370 dew-point measurement from −70 to +10 °C Td/f
- Two two-wire 4–20 mA outputs
- Certified configurations for hazardous gas and dust areas, up to Zone 0 / 20
- Detachable probes and traceable calibration
DMP370 availability: Vaisala plans first deliveries for Q1 2027. Contact Seacom for configuration and project lead time.
16 other products in the same category:
The Vaisala HMM170 provides accurate and stable humidity and temperature measurement for demanding environmental chambers, including vacuum and pressurised applications.
- Humidity accuracy up to ±1.0% RH
- Temperature measurement from −70 to +180 °C
- Modbus RTU and three configurable analog outputs
- Probe heating, sensor warming and chemical-purge options
The Vaisala HMM100 provides reliable humidity measurement and a configurable analog output for integration into environmental chambers and OEM equipment.
- 0–100% RH measurement range
- Relative-humidity or dew-point output
- Current and voltage output options
- Plastic or stainless-steel probes for temperatures up to +180 °C
The Vaisala HMDW80 Series provides cost-effective humidity and temperature measurement for routine HVAC and building-automation applications.
- Humidity accuracy up to ±3% RH
- Wall, duct and outdoor installation models
- Current or voltage output configurations
- Replaceable INTERCAP® humidity sensor
The Vaisala HMM105 provides reliable humidity measurement for integration into environmental chambers, incubators and OEM equipment.
- 0–100% RH measurement range
- I2C output for relative humidity or dew point
- Detachable 12 mm probe with 300 mm flexible cable
- Probe withstands +180 °C continuously and +200 °C temporarily
The Vaisala HMT140 Wi-Fi Data Logger has been discontinued and is no longer recommended for new monitoring systems.
- Primary replacement: Vaisala RFL100 with AP10 VaiNet Access Point
- Existing HMT140 installations can continue to be supported
- Migration should be checked against the existing sensor and input type
- Contact Seacom for replacement selection and viewLinc compatibility
The Vaisala PTU300 combined barometric pressure, relative humidity and temperature in one transmitter. The series is discontinued and has been replaced by a suitable Indigo520 barometric-pressure configuration with an application-specific HMP probe.
- Legacy three-in-one pressure, humidity and temperature transmitter
- PTU301, PTU303, PTU304, PTU305, PTU307 and PTU308 variants
- Former applications include laboratories, meteorology and semiconductor measurement
- Current replacement platform: Indigo520 with barometric-pressure measurement
- Humidity probe selected according to mounting and process conditions
- Existing wiring, outputs and process connections require migration review
The Vaisala HMD60 Series provides high-accuracy humidity and temperature measurement for demanding HVAC ducts and light-industrial applications.
- Humidity accuracy up to ±1.5% RH
- Temperature accuracy up to ±0.1 °C
- Analog, Modbus RTU and BACnet MS/TP options
- Robust IP66 metal enclosure
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 HMP3 is a high-accuracy, field-maintainable probe for industrial HVAC, air-handling units, cleanrooms, paint booths and environmental chambers.
- Humidity accuracy up to ±0.8% RH
- Temperature measurement from −40 to +120 °C
- Field-replaceable filter and HUMICAP sensor option
- Standalone Modbus RTU or Vaisala Indigo transmitter operation
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 HMX110 Series provides accurate humidity and temperature measurement for demanding indoor, duct and outdoor HVAC applications.
- Humidity accuracy up to ±2% RH
- Wall, duct, outdoor and immersion models
- 4–20 mA or Modbus RTU configurations
- Traceable calibration certificate included
The Vaisala HMP110 is a high-accuracy humidity and temperature probe designed for demanding equipment integration, environmental chambers, data loggers, incubators and controlled-environment applications.
It provides ±1.5% RH accuracy, a 0–100% RH range, −40 °C to +80 °C temperature measurement, a chemically resistant HUMICAP 180R sensor and analog or Modbus RTU output options.
The Vaisala MGP261 measures methane, carbon dioxide and humidity directly in raw biogas. Its in-situ design avoids a separate sampling system and helps operators monitor gas quality while protecting downstream equipment.
- Measures CH4, CO2 and water vapour in one probe
- 0–100 vol-% measurement range for methane and carbon dioxide
- Humidity output as 0–25 vol-% H2O or −10 to +60 °C dew point
- Heated optics help prevent condensation in wet biogas
- Three isolated 4–20 mA outputs and RS-485 Modbus RTU
- Ex-certified construction for direct installation in hazardous process areas
The Vaisala HMP4 provides high-accuracy humidity and temperature measurement in compressed air, breathing air, industrial gases, vacuum systems and other processes operating at pressures up to 100 bar.
- Operating pressure below 100 bar, including vacuum applications
- Humidity accuracy up to ±0.8% RH
- Temperature range from -70 °C to +180 °C
- Standalone Modbus RTU or connection to an Indigo transmitter
The Vaisala GMW90 Series provides stable wall-mounted carbon-dioxide and temperature measurement, with optional humidity, for demanding HVAC and building-automation applications.
- Carbon-dioxide measurement from 0 to 5000 ppm
- CO₂ accuracy up to ±(30 ppm + 2% of reading)
- Temperature measurement from −5 to +55 °C
- Optional HUMICAP® relative-humidity measurement from 0 to 95 %RH
- Voltage, current or Modbus RTU output models
- Display and CO₂ status-indicator options
- Field-exchangeable calibrated measurement modules
- Traceable three-point CO₂ calibration certificate included
The Vaisala HMT120 and HMT130 provide accurate, stable humidity and temperature measurement for cleanrooms, laboratories, data centres and demanding HVAC applications.
Product transition: HMT120/HMT130 are expected to be phased out. For new projects, the Vaisala Origo10 is the recommended replacement platform.
- Humidity accuracy up to ±1.5% RH
- HMT120 loop-powered 4–20 mA output
- HMT130 voltage outputs, RS-485 and relay
- Interchangeable fixed or remote measurement probe
- Origo10 recommended for new installations