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<< Click to Display Table of Contents >> Navigation: Humidity & Temperature Devices > Transmitter > HF7A > Device Description |
The HF7 series offers the following user functions:
• User configurable settings
• Calculation of the dew or frost point
• Humidity temperature calibration and adjustment
• Simulator mode
This circuit type provide linear analog outputs signals for transmission over a length of cable to a remote display, recorder, controller or data processing unit and can be used to measure humidity only, temperature only or both parameters.
Wire |
Mount type |
Output |
Display |
|
HF732A |
3-Wire |
Q |
0/4...20mA 0...1/2/5/10V |
No Display |
HF732A |
3-wire, analog outputs |
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15 to 40 VDC (see note below) or 13 to 28 VAC. With both output circuits closed, the maximum current consumption is 100 mA for DC powered devices and 250 mA for AC powered devices.
Note: depending on the type of output signal, the HF73 will operate with the following minimum voltage
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The HF7 measures relative humidity with a ROTRONIC Hygromer® HT-1 capacitive sensor and temperature with a Pt100 RTD.
Using the ROTRONIC HW5 or HygroSoft software, the HF7 can be configured by the user to calculate either the dew point or the frost point.
With the ROTRONIC HW5 or HygroSoft software any of the two analog output signals can be made to correspond to one of the following:
• Relative humidity
• Temperature
• Dew or frost point
Any output can also be disabled.
The scale of each analog output can be set within the numerical limits of -999.99 and 9999.99.
The D/A converters used to generate the analog output signals feature a 16-bit resolution and exhibit a small positive offset at the bottom of the signal range as indicated below:
Signal type |
Maximum offset at range bottom |
0…1 V |
10 mV |
0…2 V |
20 mV |
0…5 V |
50 mV |
0…10 V |
100 mV |
0…20 mA |
0.2 mA |
4…20 mA |
No offset |
The ROTRONIC HW5 or HygroSoft software allows changing the type of output signal to one of the following: 0…20 mA, 4…20 mA, 0…1V, 0...2V, 0…5V or 0…10V. Both output signals are automatically configured with the same signal type. No calibration or adjustment is required after changing the type of output signal.
In the case of voltage output signals, load requirements apply to the external device or circuit connected to the HF732A transmitter. These requirements are defined in the “ Operating modes and wiring” chapter.
The service connector is a UART digital interface (Universal Asynchronous Receiver Transmitter) with a mini-USB type connector. This allows connecting the HF7 either to a PC running the ROTRONIC HW5 or HygroSoft software or to a probe input of another instrument that is compatible with the HygroClip Advanced (HC2A) probes. In both cases a service cable is required. See “ Maintenance” for the location of the service connector and for the type of service cable to be used.
•Connecting the HF7 to a PC is used to configure the HF7, gain access to the HF7 functions such as humidity and temperature adjustment, read data from the HF7 on the PC and update the AirChip3000 firmware.
•Connecting the HF7 to the probe input of another instrument is useful only when the other instrument has its own display and keypad, and has an internal menu equivalent to the menu of the HP23 hand-held calibrator. The connection allows showing the data measured by the HF7 on the other instrument display and also allows using the other instrument internal menu to do for example a humidity and temperature adjustment of the HF7.
A dust filter is required to protect the sensors against dust particles and high air velocity. The probe of the HF7 is equipped with a metal filter carrier SPA-SS. The filter insertion must be ordered separately. Filter SPA-SSS is suitable for most applications.