Analog Outputs; Parameters - TESTO 6681 Profibus Instruction Manual

testo 6681 Profibus
16

1.2.6 Analog outputs

For analog outputs, the testo 6681 has either
2 or optionally 3 current outputs of 4 to 20 mA/0 to 20 mA (4-wire) or
2 or optionally 3 voltage outputs of 0 to 1 V/0 to 5 V/0 to 10 V (4-wire).
The transmitter can be ordered with a third analog output as an option.

1.2.7 Parameters

The following parameters are displayed:
Relative humidity in %RH (technical)

Relative humidity in % WMO* (calculation according to the WMO

standard)
Temperature °C and °F

Dewpoint in °Ctd and °Ftd

Absolute humidity in g/m³ and gr/ft³

Degree of humidity in g/kg and gr/lb

Enthalpy in kJ/kg and BTU/lb

Psychrometer temperature in °Ctw and °Ftw

Water vapour partial pressure in hPa and "H

Water content in ppm

Dewpoint of H

Mixture humidity H

*It is possible that condensation appears as of a displayed humidity
starting from 70 % and is shown on the display. This unit is used in
meteorology, for example. According to the WMO, the Magnus
coefficient is used for sub-cooled water in the calculation of relative
humidity.
- 1.2 Product description
If the Profibus module is integrated directly into the
testo 6681 humidity transmitter (order code B77), it has two
current outputs 4 ...20 mA.
vol
O mixture in °Ctm and °Ftm
2 2
O in %RH
2 2
Calculated humidity variables correspond to the medium of
air. With other gases/gas compositions, deviations may
occur, e.g. with the enthalpy
and % vol
m
O (inch H O)
2 2