Vaisala PTB210 SERIES Guide de l'utilisateur télécharger pdf (Page 21)

Chapter 4 ________________________________________________________________ Operating

VAISALA _______________________________________________________________________ 19

.CALD Setting the Calibration Date

With this command, the last calibration date can be stored in the

memory of the barometer.

.CALD.xxx

xxx = calibration date; max. 15 characters

Example:

.CALD.991015<cr>

Setting the RS485 Terminating

Resistor On/Off

The PTB210 series barometers have a built-in RS485 terminating

resistor, which is set, as default, OFF. The resistor can be set either ON

or OFF with the .ROFF/.ROFF commands. If the barometer is in the end

of the serial line, the resistor should be set ON, especially, when long

cables are used.

In case several barometers are connected to same line, only the

resistor of the last one is set ON, with the others it should be OFF. This

prevents formation of excessive load on the line. The maximum

amount of barometers on same line is 32.

At the end of the serial bus there must be a PTB210 barometer, a

dynamic line adapter or a line master (see figure below).

HOST

COM PUTER

PTB210

X/T

RX / T X

120R

33nF

DYNAM IC LINE TERMINATION REQUIRED

IF NO DEVICE AT THE END OF THE BUS

..........

1 2 ... 16 17 18 19 20 21 22 23 24 25 26 ... 31 32

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Vaisala PTB210 SERIES Guide de l'utilisateur Page 21