Vaisala DMT345 and DMT346 High-Temperature Dew Point Transmitters – Discontinued

Vaisala DMT345 and DMT346 High-Temperature Dew Point Transmitters

The Vaisala DMT345 and DMT346 provided direct dew-point measurement in hot industrial drying processes. Both models are discontinued and replaced by Vaisala DMP5 or DMP6 smart probes with an Indigo transmitter.

  • DMT345: former solution for processes up to +180 °C
  • DMT346: former solution for very hot processes up to +350 °C
  • DMT345 replacement: DMP5 with a suitable Indigo transmitter
  • DMT346 replacement: DMP6 with a suitable Indigo transmitter
  • Direct in-process measurement without a conventional sampling system
  • Contact Seacom for mechanical and electrical migration review

Vaisala DMT345 and DMT346 High-Temperature Dew Point Transmitters

The Vaisala DMT345 and DMT346 provided direct dew-point measurement in hot industrial drying processes. Both models are discontinued and replaced by Vaisala DMP5 or DMP6 smart probes with an Indigo transmitter.

  • DMT345: former solution for processes up to +180 °C
  • DMT346: former solution for very hot processes up to +350 °C
  • DMT345 replacement: DMP5 with a suitable Indigo transmitter
  • DMT346 replacement: DMP6 with a suitable Indigo transmitter
  • Direct in-process measurement without a conventional sampling system
  • Contact Seacom for mechanical and electrical migration review

Product status: The Vaisala DMT345 and DMT346 are discontinued. Vaisala identifies DMP5 and DMP6 with an Indigo500 Series transmitter as their current equivalents: use DMP5 for high-temperature processes up to +180 °C and DMP6 for very-high-temperature processes up to +350 °C.

Legacy Direct Measurement in Hot Industrial Processes

The Vaisala DMT345 and DMT346 were developed for dew-point and humidity measurement in industrial drying processes where ordinary probes cannot tolerate the process temperature. Direct installation avoided long sampling lines, sample cooling and trace heating, helping the measurement represent the real conditions inside the process.

Typical applications included industrial ovens, kilns, dryers, food processing, ceramics, timber drying and other hot, low-humidity processes. The correct model depended primarily on the process-temperature range and the required probe installation.

DMT345 or DMT346?

Selection pointDMT345DMT346
Legacy application Hot and dry industrial processes Very-hot industrial processes
Process-temperature capability Up to +180 °C Best performance from approximately +140 to +350 °C
Probe arrangement Long stainless-steel probe with adjustable installation depth Probe installed through a passive cooling set
Cooling requirement No separate cooling system normally required Passive cooling set supplied as part of the measurement arrangement
Current equivalent DMP5 + Indigo transmitter DMP6 + Indigo transmitter

Current Replacement: DMP5 or DMP6

Selection pointDMP5DMP6
Replaces DMT345 DMT346
Best application Direct measurement in hot processes, ovens and dryers Direct measurement in very-hot processes and furnaces
Probe-head operating range −40 to +180 °C +100 to +350 °C for direct high-temperature operation
Dew-point range −40 to +100 °C Td/f −25 to +100 °C Td/f
Dew-point accuracy Up to ±2 °C Td/f Up to ±2 °C Td/f
Temperature measurement 0 to +180 °C; ±0.4 °C at +100 °C Cooling arrangement protects the sensor; select a separate temperature measurement if required by the application
Mechanical arrangement Long probe; optional flange and adjustable insertion depth Probe with passive cooling set and configurable cooling fins
Standalone communication Modbus RTU over RS-485 Modbus RTU over RS-485
Portable and service tools Indigo80 and Vaisala Insight software Indigo80 and Vaisala Insight software

Explore the Vaisala DMP5 for processes up to +180 °C

Explore the Vaisala DMP6 for processes up to +350 °C

DMP6 Passive Cooling for Very-Hot Processes

The DMP6 uses a passive cooling set to conduct heat away from the probe head and keep the sensor within its permitted temperature. The system has no moving parts and requires no cooling water, compressed air or separate electrical supply.

The cooling-fin arrangement must match the actual process temperature and air movement. High gas velocity can change the cooling performance, so the probe should be commissioned under representative conditions and its diagnostic values checked after stabilisation.

DMP6 installation limit: the process may reach +350 °C, but the sensor itself must remain within its permitted temperature. Cooling-set installation, insertion depth, cooling fins and process velocity must therefore be reviewed as one complete arrangement.

Selecting the Indigo Transmitter

DMP5 and DMP6 include Modbus RTU and can operate as standalone smart probes. Add an Indigo transmitter when the installation requires a local display, analog signals, relays, additional power options, data logging or Ethernet connectivity.

TransmitterTypical reason to select itMain system features
Indigo201 Compact single-probe installation requiring analog outputs and relays Three analog outputs and two relays
Indigo202 Compact single-probe installation using Modbus RTU and relays Digital communication and two relays
Indigo300 Rugged local display with straightforward analog integration Metal enclosure, colour display and up to three analog outputs
Indigo510 Flagship single-probe installation Two isolated analog outputs, Ethernet web interface and Modbus TCP
Indigo520 Dual-probe or relay-intensive installation Two probe inputs, four isolated analog outputs, two relays, logging and Modbus TCP
Indigo80 Portable commissioning, spot-checking and service work Connect up to two compatible probes for display, diagnostics, data logging, calibration and adjustment

Explore Vaisala Indigo201 and Indigo202 transmitters

Explore the Vaisala Indigo300 transmitter

Compare Vaisala Indigo510 and Indigo520 transmitters

Explore the Vaisala Indigo80 handheld indicator

Other Vaisala DMP Probes Available from Seacom

ProbeMain strengthTypical applicationProduct page
DMP1 Fixed probe for low-humidity rooms Battery dry rooms and semiconductor areas View Vaisala DMP1
DMP5 Long probe for temperatures up to +180 °C Ovens, dryers and high-temperature processes View Vaisala DMP5
DMP6 Passive cooling for temperatures up to +350 °C Very-hot dryers, ovens and furnaces View Vaisala DMP6
DMP7 Short remote probe for limited spaces Compact equipment, dry rooms and semiconductor tools View Vaisala DMP7
DMP8 Adjustable insertion for pressurised pipelines Compressed air and pressurised industrial gases View Vaisala DMP8

Information Needed for Replacement

  • Complete DMT345 or DMT346 order code
  • Normal, minimum and maximum process temperatures
  • Required dew-point and temperature ranges
  • Gas composition, pressure and flow velocity
  • Process-wall and insulation thickness
  • Existing flange, insertion depth and available clearance
  • Analog outputs, relays and communication requirements
  • Power supply, display, data logging and alarm requirements

The legacy probe flange or opening may not provide a direct mechanical fit for the new probe. Check insertion depth, sealing, cable routing and the surrounding temperature before manufacturing an adapter or modifying the process connection.

Existing DMT345 and DMT346 Installations

For an operating transmitter, retain its order code, probe arrangement, output scaling, relay settings, communication configuration, installation drawings and calibration history. These details are necessary for service support and for specifying the correct DMP and Indigo replacement.

A functioning legacy transmitter does not need to be removed solely because it is discontinued. Plan the change according to calibration status, spare availability, shutdown access and the risk that measurement failure presents to production.

Vaisala DMT345 and DMT346 Replacement Support in Malaysia

Seacom Process Instruments supports existing Vaisala DMT345 and DMT346 installations in Malaysia and supplies current DMP5, DMP6 and Indigo transmitter configurations for industrial dryers, ovens, kilns and other high-temperature processes.

Our team can assist with process-temperature review, cooling-set selection, insertion depth, mounting flanges, Indigo transmitter configuration, analog and digital integration, commissioning and calibration planning.

Contact Seacom with the legacy model code, process-temperature range, dew-point requirement, gas velocity, process dimensions, outputs and control-system details so we can assess the appropriate DMP5 or DMP6 replacement arrangement.

Download

  DMP6 Catalogue   (194.41k)

  DMP5 Catalogue   (175.49k)

  Indigo200 Catalogue   (204.62k)

  Indigo 500 Catalogue   (581.96k)

  DMT345 DMT346 Catalogue   (456.92k)

  DMT345 Order Form   (88.63k)

  DMT346 Order Form   (89.9k)

  Indigo300 Transmitter Catalogue   (366.5k)


Specific References

12 other products in the same category:

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Vaisala DMT143 and DMT143L Miniature Dew Point Transmitters

Vaisala DMT143 and DMT143L Miniature Dew Point Transmitters

Vaisala DMT143 and DMT143L Miniature Dew Point Transmitters

The Vaisala DMT143 and DMT143L provide compact, dependable dew-point measurement for small industrial dryers, compressed-air systems, glove boxes and OEM equipment.

  • Dew-point measurement range across the family from −70 to +60 °C Td/f
  • Accuracy up to ±2 °C Td/f
  • Vaisala DRYCAP® technology with automatic calibration
  • Resistant to condensation, compressor oil and particulate contamination
  • Analog output and RS-485 with Modbus RTU options
  • Compatible with the Vaisala Indigo80 handheld indicator
Smart Dew Point Probe and Transmitter DMP7

Vaisala DMP7 Compact Dew Point Probe for Tight Spaces

The Vaisala DRYCAP® Dew Point and Temperature Probe DMP7 is designed for accurate low-humidity measurement where installation space is limited.

  • Short 41 mm probe for remote installation in tight spaces
  • Dew point measurement range from −70 to +80 °C Td/f
  • Pressure-tight installation for processes from 0 to 10 bar
  • Use with Modbus RTU, an Indigo transmitter or the portable Indigo80 handheld indicator
  • Suitable for dry rooms, compressed air, industrial drying and semiconductor equipment
Vaisala DMP6 Dew Point Probe for Processes up to 350 °C

Vaisala DMP6 Dew Point Probe for Processes up to 350 °C

The Vaisala DRYCAP® Dew Point Probe DMP6 measures humidity directly inside very hot industrial processes using a robust probe and passive cooling set.

  • Direct in-line measurement at process temperatures from +100 to +350 °C
  • Dew point measurement range from −25 to +100 °C Td/f
  • Passive cooling requires no power, cooling water or moving components
  • Built-in Modbus RTU or integration with Vaisala Indigo transmitters
  • Connect to Indigo80 for portable display, diagnostics, configuration and field calibration
Vaisala DPT146 Dew Point and Pressure Transmitter – Discontinued

Vaisala DPT146 Dew Point and Pressure Transmitter – Discontinued

Vaisala DPT146 Dew Point and Pressure Transmitter

The Vaisala DPT146 combines dew-point and process-pressure measurement in one compact transmitter for compressed-air systems. This model is discontinued and should not be selected for new projects.

  • Dew-point measurement from −70 to +30 °C Td
  • Absolute-pressure measurement from 1 to 12 bar
  • Pressure-compensated dew point and ppm calculation
  • Analog outputs and RS-485 with Modbus RTU
  • Contact Seacom for existing-unit support and replacement assessment
Indigo200 Series Transmitters for Vaisala smart probes for Vaisala Smart Probes

Vaisala Indigo200 Series Transmitters

Vaisala Indigo200 Series Transmitters

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
Vaisala Indigo510 Indigo520 Malaysia

Vaisala Indigo510 and Indigo520 Flagship Transmitters

Vaisala Indigo510 and Indigo520 Flagship 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
Vaisala DPT145 SF6 Multiparameter Transmitter – Discontinued

Vaisala DPT145 SF6 Multiparameter Transmitter – Discontinued

Vaisala DPT145 Multiparameter Transmitter for SF6 Gas

The Vaisala DPT145 provides online dew-point, pressure and temperature measurement for SF6-insulated electrical equipment. The model is being discontinued and should not be specified for new projects.

  • Measures dew point, pressure and temperature
  • Calculates SF6 density, normalised pressure and moisture in ppm
  • RS-485 communication with Modbus RTU
  • Contact Seacom for availability and replacement assessment
Vaisala Dewpoint Probe DMP1

Vaisala DMP1 Dew Point and Temperature Probe for Dry Rooms

The Vaisala DMP1 Dew Point and Temperature Probe provides fast, dependable low-humidity measurement for dry rooms and moisture-sensitive manufacturing areas.

  • Dew point measurement range from −70 to +80 °C Td/f
  • Fast response for detecting changes across large dry rooms
  • Modbus RTU communication or integration with Vaisala Indigo transmitters
  • Connect to Indigo80 for portable display, data logging, diagnostics and field calibration
  • Suitable for battery production, semiconductor manufacturing and controlled dry environments
Vaisala DMT132 Dew Point Transmitter for Refrigerant Dryers

Vaisala DMT132 Dew Point Transmitter for Refrigerant Dryers

Vaisala DMT132 Dew Point Transmitter for Refrigerant Dryers

The Vaisala DMT132 is a compact and economical dew-point transmitter designed to verify refrigerant-dryer performance by measuring the actual outlet-air dew point.

  • Dew-point measurement range from −30 to +50 °C Td/f
  • Accuracy up to ±1 °C in the typical refrigerant-dryer range
  • Two-wire, loop-powered 4–20 mA output
  • Operating pressure up to 20 bar
  • Resistant to condensation and compressor oil
  • Optional warning LED and loop-powered display
Vaisala DMT340 Dew Point and Temperature Transmitter – Discontinued

Vaisala DMT340 Dew Point and Temperature Transmitter – Discontinued

Vaisala DMT340 Dew Point and Temperature Transmitter Series

The Vaisala DMT340 Series provided configurable dew-point and temperature measurement for industrial low-humidity applications. The series is discontinued and replaced by Vaisala Indigo500 transmitters with DMP7 or DMP8 smart probes.

  • Former models: DMT341, DMT342, DMT344, DMT347 and DMT348
  • Designed for dry rooms, industrial dryers, compressed air and process gases
  • Legacy display, data logging, analog, relay and communication options
  • Use DMP7 for compact, wall-mounted or tight-space applications
  • Use DMP8 for pressurised processes and pipelines
  • Pair the selected probe with an Indigo500 transmitter
Vaisala DMP5 Dew Point Probe for Processes up to 180 °C

Vaisala DMP5 Dew Point Probe for Processes up to 180 °C

The Vaisala DRYCAP® Dew Point and Temperature Probe DMP5 measures humidity directly in hot industrial processes with a long stainless-steel probe and adjustable installation depth.

  • Direct in-line measurement at process temperatures up to +180 °C
  • Dew point measurement range from −40 to +100 °C Td/f
  • Long probe reaches through insulation and thick process walls
  • Built-in Modbus RTU or integration with Vaisala Indigo transmitters
  • Connect to Indigo80 for portable display, diagnostics, configuration and field calibration
Dew Point Probe DMP8

Vaisala DMP8 Dew Point Probe for Pressurised Pipelines

The Vaisala DRYCAP® Dew Point and Temperature Probe DMP8 provides reliable low-humidity measurement in pressurised pipelines with adjustable installation depth.

  • Dew point measurement range from −70 to +80 °C Td/f
  • Designed for pressurised processes from 0 to 40 bar absolute
  • Adjustable insertion depth with ISO R 1/2 or NPT 1/2 process connection
  • Optional ball-valve kit permits insertion and removal without shutting down the process
  • Use with Modbus RTU, an Indigo transmitter or the portable Indigo80 handheld indicator
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