Mettler Toledo GPro 500 Kurzanleitung Zur Einrichtung Seite 21

Quick Setup Guide TDL GPro™ 500
­
20.9
B
%V O
2
20.9
B
%Trm
O –TDL
2
u
Commissioning
20.9
B
%V O
2
20.9
B
%Trm
u
Pressure=External
20.9
B
%V O
2
20.9
B
%Trm
Ain 4 mA = 940.0 mbar
u
Ain 20 mA = 2000. mbar
20.9
B
%V O
2
20.9
B
%Trm
u
Pressure=fixed
20.9
B
%V O
2
20.9
B
%Trm
u
Pressure=1013. mbar
20.9
B
%V O
2
20.9
B
%Trm
u
Temperature=External
TDL­Commissioning­(path: Quick Setup / TDL / Commissioning)
While in measurement mode press the key [MENU] . Press the
select the TDL and then the Commissioning menu item.
First, select the type of pressure compensation selected:
– External: current external pressure value coming from a pressure transducer
of 4.. 20 mA analog output
– Fixed: pressure compensation uses a fixed value to be set manually.
Note: if this pressure compensation mode is selected, a consider-
able gas concentration measurement error resulting from a non-
realistic pressure value can take place.
If External compensation is selected, then the minimum (4 mA) and maximum
(20 mA) analog output signals from the pressure transducer must be mapped
to the corresponding Analog input of the TDL. Key in the minimum and maxi-
mum values of the pressure in the following units:
– hPa – mmHg
– psi – kPa
In general, METTLER TOLEDO recommends the use of absolute pressure trans-
ducers for more accurate signal compensation over a broad pressure range.
If, however, small pressure variations around atmospheric pressure are to be
expected, relative pressure sensors will produce better results; but the variations
of the underlying barometric pressure will be ignored.
For relative pressure sensors, the minimum and maximum values must be
mapped so that the TDL can interpret the analog pressure signal as "absolute",
i.e. a fixed barometric pressure of 1013 mbar (for example) has to be added to
the mapped values.
If Fixed compensation is selected, the fixed pressure value with which the mea-
surement signal will be calculated has to be keyed in manually. For the fixed
pressure, the following units can be used:
– hPa – mmHg
– psi – kPa
If External compensation is selected, then the minimum (4 mA) and maximum
(20 mA) analog output signals from the temperature transducer must be
mapped to the corresponding Analog input of the TDL. Key in the minimum and
maximum values of the temperature in °C.
– mbar
– mbar
or key to
m .
21