Vaisala MMT330 - Manual (Page 79)

Chapter 4 _________________________________________________________________ Operation
VAISALA ________________________________________________________________________ 79
User Port Connection
Use suitable serial cable between the user port RxD, GND and TxD
screw terminals and the PC serial port, see Figure 48 below.
Table 13 Default Serial Communication Settings for the User
Port
Parameter Value
Bauds 4800
Parity Even
Data bits 7
Stop bits 1
Flow control None
0506-033
Figure 48 Connection Example between PC Serial Port and User
Port
Connections to pins 4,6,7 and 8 on PC serial port are required only if you
are using software requiring hardware handshaking.
User Port Operating Modes
When the transmitter is powered up, it will behave according to its
configured operating mode:
- In STOP mode, the transmitter outputs the software version and the
command prompt (if echo is on).
- In RUN mode a measurement output starts immediately.
- In SEND mode one measurement message is printed and command
prompt is displayed (if echo is on).
- In POLL or MODBUS mode, the transmitter does not output anything
after power-up.
For a description of the modes, see section SMODE on page 108.
NOTE RS-232 User Port cannot be used when a communication module
(LAN, WLAN, or RS-422/485 interface) has been installed.
1 2 3 4 5
6 7 8 9
+
–
RxD
GND
TxD
Ch1+
Ch1–
Ch2+
Ch2–
ANAL
OG
O
UT
PUT
S
US
ER P
ORT
POWE
R
RS
-232
10…
36 V
=
24 V
~
IOIOI