OTT PLS - Setting Gravitational Acceleration; Setting Water Density; Setting Depth Measurement Mode

Command Response Description
䊳 Set/read local gravitational acceleration
aOXG<value>!
aOXG!
a<value><CR><LF>
a<value><CR><LF>
Set local gravitational acceleration
Read out local gravitational acceleration
a – Sensor address
<value> – b.eeeee
b – numbers before the decimal point
c – numbers after the decimal point
Value range: 9.78036 … 9.83208 m/s
2
Factory setting = 9.80665 m/s
2
The gravitational acceleration at the earth's surface fluctuates
between 9.78036 m/s
2
at the equator and 9.83208 m/s
2
at
the poles. Also, it decreases by 0.003086 m/s
2
for each
kilometer of elevation above sea level.
Formula for the local gravitational acceleration "g" in m/s
2
:
g = 9.780356 (1 + 0.0052885 sin
2
α – 0.0000059 sin
2
2α)
– 0.003086h
α latitude; h = height above sea level in km
(Source: Jursa, A.S., Ed., Handbook of Geophysics and the
Space Environment, 4th ed., Air Force Geophysics Laborato-
ry, 1985, pp. 14-17).
Example
Local gravitational acceleration in Kempten: At a height
above sea level of 669 m and a latitude of 47.71°, a local
gravitational acceleration of 9.80659 m/s
2
results.
Note
The OTT PLS is preset to an average value for Germany
(Kassel). The measurement deviation caused by gravitational
acceleration is ±3 mm in Germany (Flensburg – Oberstdorf).
This measurement error is compensated by inputting the
local gravitational acceleration.
䊳 Set/read average water density
aOXR<value>!
aOXR!
a<value><CR><LF>
a<value><CR><LF>
Set medium water density
Read out medium water density
a – Sensor address
<value> – b.eeeee
b – numbers before the decimal point
a – numbers after the decimal point
Value range: 0.50000 … 2.00000 kg/dm
3
Factory setting = 0.99997 kg/dm
3
(at 3.98 °C)
With this command you can set the actual density of the
water at your station for level/depth measurement. For
example, this is worthwhile at stations with brackish water.
䊳 Set/read depth measurement measuring mode
aOAA<value>!
aOAA!
a<value><CR><LF>
a<value><CR><LF>
Set measuring mode depth measurement
Read out measuring mode
a – Sensor address
<value> – +0 = depth measurement measuring mode
deactivated
+1 = depth measurement measuring mode
activated
Caution
If settings for the parameters "Offset", "Reference value",
"Upper limit" or "Lower limit" have been made before
changing the measuring mode, they must be reset! There is
no automatic conversion of the parameters set!
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