Vaisala HMP228 - Manual (Page 45)

HMP228
M210282en-A Operating Manual
39
24V
Sensor connections
Current loop or
RS485 module
Ch1 Ch2
+ - nc
Tx
GND
Rx
- - + +
X16
Figure 4.9.2 Forcing the serial port settings back to factory settings
When the jumper is inserted the serial line factory settings become valid, but
only temporarily. The transmitter must be given new settings; otherwise
the transmitter uses the old, unknown settings after power-up. When the
new settings have been given, the transmitter must be reset. The jumper must
be removed before the transmitter is reset; if the jumper is in place when
power is turned on, the transmitter does not work.
After jumper insertion the transmitter is in STOP mode, ready to receive
commands.
The same method is used when the transmitter is in POLL mode and the user
has forgotten its address.
CAUTION
Inserting a jumper in any other place in connector X16
voids the guarantee of the transmitter.