ROTRONIC HF62 - Manual (Page 15)

E-M-HF62-V1_11
Rotronic AG
Bassersdorf, Switzerland
Document code Unit
Instruction Manual
Document Type
HygroFlex HF62 Humidity Temperature
Transmitters: User Guide
Document title
Page 15 of 27
© 2008; Rotronic AG E-M-HF62-V1_11
Measuring humidity or temperature only
Operation of the HF62 does not require both current loops to be closed. When using the HF62 to measure
either humidity only or temperature only, power and close only the loop that is being used. Any unused output
of the HF62 can be disabled with the ROTRONIC HW4 software.
o
Model with LC display: the humidity loop must be closed for the display to operate.
6.3.2 HF62 with direct RTD option: 2-wire, loop powered transmitter
Electrical diagram
The maximum permissible cable length
connecting the HF62 to other devices is
determined by the total resistance resulting
from the addition of the cable resistance and
that of the devices connected in series with
the unit. This resistance should not exceed
500 ohms.
Terminal block diagram
Terminals Description
K1-1: H-OUT
Relative humidity or dew point (+)
OUT-1
K1-2: V+ Power supply: 10…28 VDC (+)
Terminals Description
K3-1 Pt100 direct - S
K3-2
Pt100 direct - AS
K3-3 Pt100 direct – AR
K3-4 Pt100 direct - R
6.3.3 Grounding
We generally recommend grounding the (-) side of the power supply, especially if the electronics will be
subjected to a low humidity environment (35 %RH or less).