Display option, General description, Power supply – ROTRONIC HF3 User Manual

Page 5: Measured parameters, E-m-hf3-v1_22, 3general description, 1 display option, 1 power supply, 2 measured parameters

E-M-HF3-V1_22

Rotronic AG
Bassersdorf, Switzerland

Document code

Unit

HygroFlex HF3 Transmitters and Thermo-
hygrostats: User Guide

Instruction Manual

Document Type

Page 5 of 27

Document title

2.1 Display option

The LC display option is available only with type R
and type S mechanical configurations. The upper line
of the display corresponds to relative humidity or dew
/ frost point and the bottom line corresponds to
temperature.

The display can be configured to show a trend
indicator on each line:

▲: increasing value
▼: decreasing value

In the event of an alarm the display shows the
symbol [ ! ] to the right of the value.

For instructions see the following HW4 manual:
E-M-HW4v3-F2-002.

The display option for the HF33 has a backlight. The display option for the HF32 does not have a backlight.

General description

3.1 Power supply

Depending on the circuit type, the HF3 requires the following power supply:

a) HF32 (2-

wire, loop powered): 10…28 VDC - depending on the load connected to the output(s). The

minimum supply voltage can be determined as follows:

V min = 10 V + (0.02 x Load*) *Load resistance in ohms.

For the maximum load of 500 , the minimum supply voltage is 10 + (0.02 x 500) = 20 VDC. With both
output circuits closed, the maximum current consumption is 40 mA.

b) HF33 (3-wire with analog outputs): 15 to 40 VDC (see note below) or 12 to 28 VAC. With both output

circuits closed, the maximum current consumption is 50 mA.

Note: depending on the type of output signal, the HF33 will operate with the following minimum voltage

0…1 V outputs:

5 VDC or 5 VAC

0…5 V outputs:

10 VDC or 8 VAC

0…10 V outputs:

15 VDC or 12 VAC

0…20 mA or 4 …20 mA outputs:

6 VDC or 5 VAC with 0 load

15 VDC or 12 VAC with 500 load

c) HF34 (3-wire): 8 to 40 VDC or 12 to 28 VAC. With both relays energized, the maximum current

consumption is 50 mA.

3.2 Measured parameters

The HF3 measures relative humidity with a ROTRONIC Hygromer

IN1 capacitive sensor and temperature

with a Pt100 RTD.