ROTRONIC MP400H - Manual (Page 14)

E-M-HM-V1_10
Rotronic AG
Bassersdorf, Switzerland
Document code Unit
HygroMet MP Humidity Temperature
Meteorological Probe: User Guide Instruction Manual
Document Type
Page 14 of 19
Document title
© 2009; Rotronic AG E-M-HM-V1_10
o Instruments connected to the same RS-485 network must use the same baud rate and each instrument
must be given a unique RS-485 address (the address requirement applies to the HygroMet MP but not to
its probe)
o RS-485 Compatibility: The communications protocol used by the HygroMet MP is the RO-ASCII
protocol. This protocol is not compatible with the protocol used by the previous generation of ROTRONIC
products. Do not connect legacy products and the HygroMet MP to the same RS-485 multi-drop network.
The specifications of the RS-485 interface are as follows:
Baud rate : 19200
Parity : none
Data bits : 8
Stop bits : 1
8 Maintenance
8.1 Service cable
Cable AC3006 is used to connect the HygroMet MP to a USB port of a PC running the ROTRONIC HW4
software. The AC3006 cable does not power the HygroMet MP and the HygroMet MP should be powered
separately.
Prior to using this cable you must install the ROTRONIC USB driver on the PC (available from the HW4 CD or
from www.rotronic-humidity.com). For instructions see the HW4 manual E-M-HW4v2-Main (§ 6.3)
8.2 Location of the service connector (mini USB type)
WARNING: the service connector is a UART interface with a mini-USB connector type. Do not connect the
service connector directly to the USB port of a PC or hub.
The service connector is located on the PCB of the HygroMet MP. To gain access to the service connector
proceed as follows:
a) Unscrew the curly cable grip from the barrel of the HygroMet MP
b) Slide back the sealing grommet over 15 cm (6”) of cable
c) Unscrew the barrel from the bulkhead of the HygroMet MP
d) Pull the barrel back to uncover the PCB
8.3 Periodic calibration check of the HC2-S3 probe
Both the Pt 100 RTD temperature sensor used in the HC2-S3 probe and associated electronics are very
stable and should not require any calibration after the initial factory adjustment.
Long term stability of the ROTRONIC Hygromer humidity sensor is typically better than 1 %RH per year.
For maximum accuracy, calibration of the probe should be verified every 6 to 12 months. Applications
where the probe is exposed to significant pollution may require more frequent verifications.
Using the HW4 software to adjust the probe connected to the HygroMet MP: