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Vaisala PTB200 User Manual

Page 15

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PTB 200

14 (28)

Digital Barometers

SSD/Operating Manual

24th February 1993

PTB200-O0284-1.1

UNIT

Setting the pressure unit

UNIT x

where
x

hPa*, kPa, mbar, inHg, mmHg, torr, psia (* factory setting).

Command UNIT is used to select the pressure unit. Type the selected
pressure unit as given above.

Example of changing the pressure unit to mbar:

>UNIT mbar

MTIM

Setting the measurement time parameters

MTIM

The MTIM command is used to set the number of measurement sam-
ples (MTIM value) integrated to get a pressure reading. The basic
measurement sample time is about 25 milliseconds. The MTIM value
can range from 4 to 255.

The MTIM factory setting of the PTB 200 A is 64; this ensures a stable
resolution of 0.01 hPa. The integration time is then 64 x 25 ms = 1600
ms. The settling time including initialization and integration time is ap-
proximately 2 s.

The MTIM factory setting of the PTB 201 A is 16; this ensures a stable
resolution of 0.1 hPa. The integration time is then 16 x 25 ms = 400 ms.
The settling time including initialization and integration time is approxi-
mately 1 s.

The MTIM value affects the settling time of the barometer: the longer
the integration time, the longer the settling time.

The FILT command also affects the integration and settling times (see
FILT command).

Example of changing the MTIM value:

>MTIM
Mtim : 64 ? 150