DMT345 and DMT346 DewpointTransmitters
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DMT345 and DMT346 Dewpoint Transmitters for High Temperature Applications Features • DMT345 measures humidity at temperatures up to 180 °C (356 °F) • DMT346 measures humidity at temperatures up to 350 °C (+662 °F) • Dew point accuracy ±2 °C (±3.6 °F) • Condensation-resistant • Unique auto-calibration feature • Analog outputs, RS-232/485, WLAN/LAN • Modbus protocol support (RTU/ TCP) • Vaisala DRYCAP® sensor provides accurate and reliable measurement with excellent long-term stability and fast response time • Graphical display and keypad for convenient operation • Optional alarm relays and mains power supply module Both transmitters incorporate the Vaisala DRYCAP® sensor, which is accurate, reliable, and stable. The sensor is condensation-resistant and is immune to particulate contamination, oil vapor, and most chemicals. The DRYCAP® sensor is notable for its swift response time and rapid recovery after getting wet. Measure Humidity Directly in Hot Processes DMT345 and DMT346 are built for direct measurement in hot processes. Therefore, there is no need for sampling systems and trace heating. As a result, high measurement accuracy and constancy are maintained. The accuracy and stability of DMT345 and the DMT346 are due to their unique auto-calibration function, developed by Vaisala. This feature allows the transmitter to perform calibration and adjustment by itself while the measured process is running. If the measurement accuracy is not confirmed, corrections are made automatically. The procedure is so quick and corrections so minor that it causes no disruption, ensuring easy maintenance and high performance. DMT345: Accurate in Hot and Dry Environments DMT345 is designed for accurate humidity measurement in hot and dry conditions. This model provides unmatched dry-end measurement accuracy at temperatures up to 140 °C; however, it can operate safely at temperatures up to 180 °C. The long and robust steel probe and an optional installation flange allow easy, adjustable installation depth through insulation for example in ovens. DMT346: Reliable in Very Hot Processes DMT346 provides the best measurement performance at process temperatures between 140 °C and 350 °C. DMT346 includes a cooling set as standard. The cooling set provides passive cooling by conducting heat away from the probe and thus reduces temperature to optimal range for the sensor. The cooling system has no moving parts, and requires no additional power or cooling utilities, so there is no risk of sensor damage due to mechanical cooling failure. Additionally, sensor warming minimizes the risk of condensation accumulating on the sensor. In low humidity conditions the combination of auto-calibration and DRYCAP® ensures accurate me

Graphical Display of Measurement Data and Trends for Convenient Operation DMT345 and DMT346 transmitters feature a large numerical and graphical display with a multilingual menu and keypad. It allows users to easily monitor operational data, measurement trends, and access measurement history for the past 12 months. The optional data logger, with real-time clock, makes it possible to generate over four years of measurement history and zoom in on any desired time or time frame. The display alarm allows tracking of any measured parameter, with freely configurable low and high limits. Versatile...

Dew Point Sensor Measurement range Accuracy Dew Point Sensor Measurement range Accuracy Vaisala DRYCAP 180S -40 ... +100 °C (-40 ... +212 °F) Td ±2 °C (±3.6 °F) Td See the accuracy graph below Vaisala DRYCAP 180S -25 ... +100 °C (-13 ... +212 °F) Td ±2 °C (±3.6 °F) Td See the accuracy graph below Temperature of measured gas (°C) Dew point accuracy vs. measurement conditions Response time 63 % [90 %] in flow rate From dry to wet: 5 s [10 s] 1 l/min and 1 bar pressure Temperature Measurement range Measurement range with sensor warming Accuracy Temperature sensor Relative Humidity Measurement...

Operating Environment, DMT345 and DMT346 ± 0.05% full scale ± 0.005%/°C full scale 0.5 mm2 (AWG 20) stranded wires recommended RS-232, RS-485 (optional) ASCII commands, Modbus RTU RS-232, USB 0.5 A, 250 VAC, SPDT 10 ... 35 VDC, 24 VAC ±20% Accuracy of analog outputs at 20 °C Temperature dependence of analog outputs Max. wire size Digital outputs Protocols Service connection Relay outputs 2+2 pcs (optional) Operating voltage Operating voltage with optional power 100 ... 240 VAC 50/60 Hz supply module Default Start-up Time Initial reading after power-up 3 s Full operation after sensor purge...

sintered filter (fixed on top of the cooling set) cooling element mounting flange cooling fins DMT345 Probe and Mounting Flange Published by Vaisala | B210723EN-G © Vaisala 2017 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 witho