Vaisala PTB220 - Manual (Page 39)

C HAPTER 4_____________________________________________________________ COMMISSIONING
V AISALA _________________________________________________________________________ 33
ENT CL
Hardware settings
Inside the barometer, there is the connector X15 (see F IGURE 4-2 ) and
the dip switch S1 (see F IGURE 4-3 ). These are used to make the main
hardware settings of the PTB220 series digital barometers.
With the connector X15, the user can select the RS 232C (RX, TX) or
TTL levels for serial communication. With TTL levels, the user also
has phase alternatives available for both input (RXD, RXD inverted)
and output (TXD, TXD inverted). See page 81 for further information
on the waveforms, voltage levels and phases of the RS232C/TTL level
serial interface signals.
TXD
RXD
X15
RX/RXD
TX
TXD
F IGURE 4-2 RS 232C/TTL level and phase selections
The half duplex two-wire RS485/422 serial interface of the PTB220
series barometers does not require any hardware settings to be made to
the barometer. See page 93 for quick reference information on how to
use the RS485/422 interface of the PTB220 series digital barometers.
Normally, the dip switch S1 settings are all OFF as in F IGURE 4-3
ON
OFF
SW1
SW2
SW3
SW4
SW5
SW6
SW7
SW8
S1
F IGURE 4-3 Basic dip switch S1 settings