Vaisala PTB220 Series Guide de l'utilisateur télécharger pdf (Page 39)

CHAPTER 4_____________________________________________________________ COMMISSIONING

VAISALA _________________________________________________________________________ 33

ENTCL

Hardware settings

Inside the barometer, there is the connector X15 (see FIGURE 4-2) and

the dip switch S1 (see FIGURE 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

TXD

FIGURE 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 FIGURE 4-3

OFF

SW1

SW2

SW3

SW4

SW5

SW6

SW7

SW8

FIGURE 4-3 Basic dip switch S1 settings

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Vaisala PTB220 Series Guide de l'utilisateur Page 39