ROTRONIC HygroMet MP402H - Manual (Page 13)

E-M-HM-V1_12
Rotronic AG
Bassersdorf, Switzerland
Document code Unit
HygroMet MP Humidity Temperature
Meteorological Probe: User Guide Instruction Manual
Document Type
Page 13 of 20
Document title
© 2009-2011; Rotronic AG E-M-HM-V1_12
6.3.2 HygroMet : 3-wire version
Electrical diagram for voltage outputs
The maximum permissible cable length can be
determined under consideration of the voltage drop
caused by the current flowing to the devices
connected to the unit. The voltage drop in the cable
depends both on cable resistance and on the
equivalent resistance of the devices connected in
parallel to the unit. The total resistance connected to
each unit output should be at least 1000 ohms.
Cable resistance should not be more than 1/1000 of
the load resistance.
Electrical diagram for current outputs
The maximum permissible cable length, connecting
the unit 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.
Wiring color code
Wire color Description
Gray Power ground
Green Power supply (+) 5…24 VDC (depends on output signal type)
White – labeled 1
Output 1 (+) – default: relative humidity or calculated
parameter
White – labeled 2 Output 1 (-) – A-GND 1
Brown Output 2 (+) – default: temperature
Pink Output 2 (-) – A-GND 2
Red RS485 (RXD)
Blue RS485 (TXD)
Black Optional: additional Pt100 RTD probe – PT S
Purple Optional: additional Pt100 RTD probe – PT AS
Orange Optional: additional Pt100 RTD probe – PT R
Yellow Optional: additional Pt100 RTD probe – PT AR
Cable shield
Drain – should be connected to power supply (-) or to an
earth ground