Vaisala HMT120 HUMICAP Humidity and Temperature Transmitters

Vaisala HMT120 Series HUMICAP Humidity and Temperature Transmitters measure relative humidity and temperature and outputs the measurements to voltage outputs and RS-485. Other quantities, such as dewpoint (Td) can be calculated from the basic RH and T values according to the device configuration. HMT130 is powered with a 10 ... 35 VDC or a 24 VAC supply (15 ... 35 VDC or 24 VAC required when using 0 ... 10 V output). It outputs two analog voltage signals with nominal 0 ... 10 V range. HMT120 has also an RS-485 digital interface and a relay.

The Vaisala HUMICAP HMT120 transmitters are suitable for clean rooms, museums, laboratories and data centers. Maintaining measurement traceability is easy due to field exchangeable intelligent measurement probes. These can be exchanged with minimal downtime and process disturbance. The humidity parameter options available are: relative humidity, dew point/frost point, wet bulb temperature, enthalpy, absolute humidity, mixing ratio, vapor pressure, and saturation vapor pressure.

Wall, remote or outdoor mounted transmitter shall incorporate a thin film polymer capacitive HUMICAP® relative humidity sensor. Electronics shall be protected from: condensation, chemicals and dust in a NEMA-4 enclosure. Sensors to be able to withstand wash down with no lasting detrimental effect to transmitter performance. Accuracy to be ± 1.5% RH between 0 to 40°C (32 to 104°F) for the 0 to 90% RH range, and ± 2.5% RH for the 90 to 100% RH range. Shall have a typical stability of ±0.5 %RH per year. Transmitter will be powered by 15 to 35VDC or 24 VAC. Transmitter with optional display shall operate over a temperature range of -20° to 60°C (-4° to +140°F) and transmitter without display shall operate -40° to 60°C (-40° to +140°F). Transmitter shall have a linear selectable output signal of 0 to 1V, 0 to 5V or 0 to 10V corresponding to 0 to 100% RH (dewpoint, enthalpy and wet bulb optional). Optional temperature sensor to be a platinum 1000* RTD having a linear selectable output signal of 0 to 1V, 0 to 5V or 0 to 10V corresponding to -40° to 60°C (-40° to +140°F) for fixed probe and -40° to 80°C (-40° to +176°F) for remote probe. Accuracy to be ±0.2°C (0.36°F) at +15 ...25 °C. Probes shall be interchangeable for minimal maintenance downtime. Transmitter shall also have the ability to calibrate relative humidity, without disturbing operation, using a single point electronic field calibrator. NIST traceable calibration and certificate included. Shall have an optional solar radiation and precipitation shield for outdoor mounting.

HMT120 transmitter's output quantities are configurable. Available quantities for outputs are limited to two at the time. These two quantities can be used freely at any outputs (display, service port and voltage outputs).

Available quantities are RH, T, T_d, T_d/f, a, x, h, T_w, p_ws, and p_w.

The default output quantities are set at the factory during order time. These factory preset quantity selections can be changed afterwards via service port if necessary.

The HMT130T and HMT130H models are single-parameter transmitters. The only output quantity of HMT130T is temperature. The output of the HMT130H can be con®gured to be any one of the humidity-related quantities (RH, T_d, T_d/f, a, x, h, T_w, p_ws and p_w).

Performance

HMT120 incorporates Vaisala HUMICAP technology that measures relative humidity accurately and reliably. Vaisala HUMICAP is resistant to dust and most chemicals. The transmitter enclosure is optimized for use in clean rooms. The smooth surface of the enclosure makes it easy to clean and the enclosure material is chosen to tolerate purifying agents. Furthermore, the cabling can be done through the back wall of the transmitter.

Interchangeable Probe

The HMT120/130 transmitters use a fully interchangeable relative humidity probe. The probe can be easily removed and replaced with a new one without having to adjust the transmitter, which allows for easy and quick recalibration of the transmitter. The probe can be adjusted using one of Vaisala’s portable meters as a reference.

Also available is a constant output probe with fixed RH and T output for convenient inspection of the monitoring system and signal transfer line.

Available Options

The HMT120 transmitters are available as wall mounted or with a remote probe. For high temperature applications or where space is limited, the remote probe is ideal. The optional LCD display shows the measurement results of selected parameters in selected units. The parameters are displayed simultaneously at two separate rows on the display.

Options

• Humidity parameter options: relative humidity, dew point/frost point, wet bulb temperature, enthalpy, absolute humidity, mixing ratio, vapor pressure, and saturation vapor pressure
• 2-wire loop-powered or 3-wire voltage output configurations
• Optional LCD display
• USB cable available for a PC connection for maintenance
• Wall-mounted or with a remote probe
• Constant output probe available
• Can be mounted outdoors using a Vaisala installation kit and the Vaisala Radiation Shield DTR504A

Dimensions

Ordering Informations

*) Voltage output value between 0...10 V

Selections in bold are included in the prices of the basic versions
Selections in italic are available at an extra cost