Vaisala WAC155 Guide de l'utilisateur télécharger pdf (Page 18)

User's Guide ______________________________________________________________________

16 ___________________________________________________________________M210822EN-A

6. Attach the unit on the top of a pole mast with the mounting clamp

as shown in Figure 17 on page 28.

7. Mount the sensors onto the cross arm. Refer to Figure 18 on page

29 and the sensors' manuals.

8. Align the cross arm as instructed in section Alignment on page 29

before erecting the mast.

Jumper Settings

RS-485 serial bus termination can be selected with the on-board jumper.

Termination is on when pins 1 and 2 are shorted, and termination is off

when pins 2 and 3 are shorted or when the jumper plug is fully

disconnected. Termination is implemented by a 120 resistor on the

component board.

In a simple point-to-point configuration where only one WAC155

transmitter is used the jumper is always in ON position. In a multidrop

configuration where several WAC155 transmitters share the single

RS-485 communication line, the termination jumper is in ON position

only at the physically farthest transmitter (i.e. at the end of the

communication line), and in OFF position at the other transmitters.

0701-017

Figure 4 RS-485 Termination

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Vaisala WAC155 Guide de l'utilisateur Page 18