Operation Manual

6. Barograph and Storm Alarm

6.1 Description

The FMD55 has an integrated precision atmospheric

pressure sensor with an amplifier and scoring logic.

The graphic range is 950 to 1080 hPa (mbar).

The pressure is continually measured and the average

evaluation is stored for 24 hours. The current value is

displayed numerically in the top right hand corner of the

LCD. The average evaluation of the past 21 to 24 hours is

shown graphically on the display. The time axis is horizontal.

The difference between two lines is one hour. The line is

intensified every three hours. The hour numerals are at the

foot of the graphic. The atmospheric pressure is depicted

vertically. The distance between two horizontal lines is

equivalent to 2 hPa. The page moves to the left every

three hours.

6.2. Calibrating the Barograph

The sensor feeder is absolutely correct and to a great

extent, temperature compensated. The barograph should

be calibrated after the initial installation and, subsequently

after every considerable change of climate caused by

positional movement.

Before calibration, the FMD55 should

be operating for 10 hours in a fixed position. For calibration

you require the absolute true atmospheric pressure reading

at your fixed position. This reading can be obtained from

the local weather station, marina or airport. Please make

sure , that there is the least possible difference in altitude

between the point where measurements were taken and

the FMD55. The calibration is very simple:

x press the <STDBY> key to set-up menu 1

x press key <2> to set-up menu 2

x press key <4> to select BAROSCOPE (barograph)

x press key <2> to enter calibration

You can now enter the indicated value by means of the

numeral keys. In case of a mistake in input delete with

<CLEAR> key.