ROTRONIC HF65 - Manual (Page 21)

E-M-HF63_65-V1_11
Rotronic AG
Bassersdorf, Switzerland
Document code Unit
Instruction Manual
Document Type
HygroFlex HF63/HF65 Humidity Temperature
Transmitters: User Guide
Document title
Page 21 of 34
© 2008; Rotronic AG E-M-HF63_65-V1_11
RS-485 terminal block
Pins K3-1 and K3-2 can be used to power all
instruments on a RS-485 multi-drop from a single
external DC power supply with adequate mA rating.
In that case, do not use pin K6-2 and pin K6-3
(normally used to power the HF65).
6.4.3
Grounding (all models)
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).
7 Operation
7.1 Minimum load requirements for the HF63 with voltage outputs
The following requirements apply to any external device or circuit connected to the HF63 transmitter with
voltage outputs:
Terminals Description
K3-1: PWR
DC (+) 15…40 VDC (+)
(optional, see note below)
K3-2: GND Ground / Power supply (-)
K3-3: D+
RS-485 Bi-directional
TX+ / RX +
K3-4: D-
RS-485 Bi-directional
TX- / RX -
RL
GND
HF63
Voltage Output
HF63 output signal Input resistance RL
0…1V >=1kOhm
0…5V >=5kOhm
0…10V >=10kOhm