MSB780(X) - User’s Guide
as follows: k = 1, q = 0. These are the factory defaults. Resetting coefficients to defaults (k = 1,
q = 0) can be done using command (adjdef), as described in section 6.40 on page 51.
Please write down the old values before altering them, for the case you would like to restore
them.
5.3 Adjusting MSB780X with more than one transducer
For MSB780X with more than one pressure transducer, each pressure transducer is adjusted
separately. To read the pressure value for each transducer d<cr> command can be used. This
command is described in chapter 6.4 on page 33. Alternatively, using the form<cr> command
you may set a message containing the pressure readings from individual pressure transducers
(P1, P2, P3, see page 39).
5.4 One pressure point adjustment
Performing adjustment at one pressure point means adjustment of offset. The output value of
the barometer is shifted by the same amount at any pressure.
This is done by altering the q coefficient only.
To adjust offset, follow these steps:
1. Read the old coefficient values and write them down. For example k = 1, q = 0. For this
use the cnf?<cr> command, as described in section 6.5 on page 34.
2. Compare the reading of the MSB780 or MSB780X against a reference.
For example the MSB780 or MSB780X reads 980.23 hPa, the reference reads 979.99
hPa.
3. Compute the correction. The correction is computed as reference - MSB780 or MSB780X,
i.e. 979.99 - 980.23 = -0.24 hPa.
4. Add the computed correction value to the old q coefficient value. In the example 0 + (-0.24)
= -0.24. This is the new q value.
5. Write the new k and q values to MSB780 or MSB780X memory using command cset<cr>,
as documented in section 6.36 on page 49.
5.5 Two pressure points adjustment
Adjusting a device in two pressure points changes both coefficients; gain and offset, i.e. k and
q. If you would like to adjust MSB780 or MSB780X using two reference pressure points, follow
this procedure:
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