Vaisala DRYCAP DMT143 - Basic Features and Options

Parameter Abbreviation Metric Unit Non-Metric Unit
ppm moisture, by volume H
2
0 ppm ppm
When dew point is below 0 °C, the transmitter outputs frost point for Td.
Dew point temperature in atmospheric pressure (T
d/f
atm) is a calculated parameter that
presents the dew point the gas would have at atmospheric pressure. For this calculation to
provide accurate results, it is important to have the correct pressure setting stored in the
transmitter. This setting is specified on the order form, and it can be changed using the RS-485
line or DM70 handheld dew point meter.
More Information
‣
DMT143 and DMT143L Transmitter Parts (page 12)
‣
DMT143 Specifications (page 69)
2.2
Basic Features and Options
• Maximum dew point measurement range of -70 ... + 60 °C (-94 ... +140 °F)
• Dew point measurement accuracy up to ±2 °C (±5.4 °F) T
d
in air or N
2
• Operating pressure range:
• DMT143: 0 ... 50 bar
a
(725 psi
a
)
• DMT143L: 0 ... 20 bar
a
(0 ... 290 psi
a
)
• Configurable for optimum dew point measurement accuracy: Pressure compensation
(fixed pressure setting or live pressure input through RS-485)
• Analog output: one output channel, selectable from:
• 0 ... 1 V (DMT143 only)
• 0 ... 5 V (DMT143 only)
• 1 ... 5 V (DMT143 only)
• 4 ... 20 mA (DMT143 and DMT143L)
• None (DMT143 and DMT143L, digital output only)
• Digital output: RS-485 (non-isolated). The following protocols are supported:
• Modbus RTU
• Vaisala Industrial Protocol
• LED for dew point level alarm and transmitter diagnostics
• DRYCAPâ polymer sensor:
• Autocalibration ensures accuracy in changing measurement conditions
• Sensor warming keeps the sensor dry in high humidity
• Sensor purge ensures long term stability
• NIST traceable (certificate included)
• Field check suitability with DM70 handheld dew point meter
DMT143 User Guide M211435EN-J
10