Manual
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
12 of 20
Document title
© 2009-2011; Rotronic AG E-M-HM-V1_12
6.3 Wiring color code
The HygroMet MP is supplied with 3m (9 ft) of PUR cable with tinned ends. Before connecting the
power, please make sure that there is no wiring error. Improper wiring may damage the HygroMet MP.
To facilitate maintenance of the HygroMet MP, keep the probe cable short. Do not replace the cable
supplied with the probe with a much longer cable. If a long length of cable is required, use an extension
cable with a maximum length of up to 330 feet (100 meters). When transmitting analog voltage signals
over a long distance, you should use separate wires for power ground and for each signal ground.
6.3.1 HygroMet: 2-wire version, loop powered
Electrical diagram
The maximum permissible cable length connecting
the HygroMet MP 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
Measuring humidity or temperature only
Unless configured to measure either humidity only or temperature only, proper operation of the HygroMet MP
requires both current loops to be closed. The HygroMet MP can be ordered from the factory to measure either
humidity or temperature only. When necessary, any unused output of the HygroMet MP can be disabled with
the ROTRONIC HW4 software. When the HygroMet MP is configured with one of the two outputs disabled,
close only the loop that is being used.
Wire color
Description
Green
Power supply (+) 10…28 VDC
White
Output 1 (+) – default: relative humidity or calculated parameter
Brown
Output 2 (+) – default: temperature
Black
Optional: additional Pt100 RTD probe
Purple
Optional: additional Pt100 RTD probe
Orange
Optional: additional Pt100 RTD probe
Yellow
Optional: additional Pt100 RTD probe
Cable shield
Drain – should be connected to power supply (-) or to an earth
ground
OUT 1
OUT 2