Vaisala HMP230 - Manual (Page 35)

HMP230 SERIES
M210225en-B User's Guide
29
In calibrating or changing the settings of the transmitter it can be more con-
venient to use the connector X17, if connector X6 is already in use. This con-
nector, however, transfers only RS 232C signals. If an RS 485/422 serial port
module or a current loop module has been installed, it has to be removed be-
fore communicating through the X17 connector.
RX GND TX
X17
Figure 27 Location and connections of connector X17
NOTE
Some PC computers can generate interferences to the
measured humidity and temperature values if the
transmitter and the PC are connected to different mains
outlets. To minimize the possibility of these interfer-
ences, always use the same mains outlet (same phase of
the mains electricity) for the PC and the power supply
of HMP230. This is especially the case when using the
serial line connector X17. The serial line connector X6
is more immune to these interferences than connector
X17.
4.4.1. Reverting to factory settings of the serial port
If the serial port settings are not known, no commands can be given via the
serial interface. The settings can be reverted to the factory settings by inserting
a jumper in connector X16. The jumper must be inserted when the power is
on!
OPENED COVER OF THE HMP230
X16
Figure 28 Forcing the serial port settings back to factory settings