Atmospheric Pressure Compensation - Ahlborn ALMEMO 2590-2A Operating Instructions Manual

Universal measuring instruments and data loggers

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Table Of Contents

Table of Contents

11. Measuring menus

If the temperature of the medium deviates from 25°C the following measuring

errors must be considered :

e.g. Errors per 10 °C

Dynamic pressure

pH probe

approx. 3.3%

For temperature compensation of these sensors there are 2 possibilities :

Enter compensation temperature

in function

Both in this function and in the measured value the symbol

Continuous temperature compensation with external temperature sensors

can be activated either via the reference channel (see 13.12.6) of the sensor to

be compensated or by configuring any temperature sensor as reference sensor

with a ´*T´ in the designation (see 13.2).

While the temperature is being measured, a point flashes

behind the symbol ´CT´

Flow values (velocity or volume flow) acquired with temperature com-



pensation can by means of ´#N´ in the designation (see 13.2) be con-

verted to standard conditions of 20°C (see Manual 6.7.5).

11.2.5

Measured variables dependent on the ambient atmospheric pressure (see Sec-

tion 13.9 Measuring range list ´with PC´) may, in the event of large deviations

from normal pressure (1013 mbar), involve certain measuring errors.

e.g. Error per 100 mbar

Rel.humidity psychrometer

Mixture ratio, capacitive

Dynamic pressure

saturation

It is advisable therefore, especially when taking measurements at appreciable

heights above sea level to take due account of the atmospheric pressure (ap-

prox. -11 mbar / 100 meters above mean sea level, MSL). On all sensors requir-

ing atmospheric pressure compensation the

atmospheric pressure

The appropriate atmospheric pressure can be entered either in

or in device programming (see 14.6) or it can be measured using an atmos-

pheric pressure sensor (reference sensor with designation ´*P´, see 13.2, Man-

ual 6.7.2). While the atmospheric pressure is being used for compensation both

in the function

appears; if it is being measured a point flashes behind

Please note that as soon as a reference sensor is disconnected nor-



mal pressure, 1013 mbar, is used.

Flow values (also volume flow with rotating vanes) acquired with at-

Compensation range

approx. 1.6%

0 to 100 °C