10
8.2 Throughput measurement with totalising
The throughput and, alternately, the total quantity are to
be displayed.
The measuring sensor has linear characteristics (in the
case of non-linear sensors, linearizing elements are to
be connected). It delivers 4 mA at rest and 20 mA at
maximum throughput, which corresponds, in this exam-
ple, to 90 l/min.
Select under “Range” the measuring range from 4 to
20 mA and, for the maximum “hi.act and minimum
“lo.act” input signals, the corresponding factory setting.
Allocate the display value 0 to the lowest input signal
“lo.act”, and the display value 1.5 (in liters/second) to
the highest input signal “hi.act”.
Set the adding counter decimal point “dp.tot” according
to the maximum expected quantity: for a 100 000 l in-
stallation, select zero decimal and, since this still is not
sufficient, extend the display range by two digits with a
“Scale” of 0.01, as to display the total volume in hecto-
liters.
Press the right key to switch between the momentary
value display and the adding counter value display.
Different factors also allow displaying the total volume
in other units, for example, with the factor 2, in 0.5-l
bottles, or, with the factor 2.6420, in gallons.
8.3 Kilometers measurement with totaling
The instantaneous speed in km/h and the total running
time of an engine on a testing stand are to be dis-
played.
The measuring sensor delivers 4 mA at rest and 20 mA
at maximum speed, which corresponds, in this exam-
ple, to 180 km/h.
Select under “Range” the measuring range from 4 to 20
mA and, for the maximum «hi.act » and minimum
«lo.act » input signals, the corresponding factory set-
ting.
Allocate the display value 0 to the lowest input signal
“lo.display”, and the display value 180 to the highest
input signal “hi.display”.
This way the device displays the instantaneous speed
in km/h.
Set the adding counter decimal point “dp.tot” according
to the maximum planned test time, for example, for a
24-hour test at maximum speed, four digits before the
decimal point will be sufficient.
The sample rate of the adding counter is 1 second. To
add the covered distance, use the factor to adjust the
speed per second: 1/3600=0.00027778, which corre-
sponds, at maximum speed, to 0.05 km/sec.
So set the factor to 0.0278 and the scale to 0.01. This
way, after 24 hours, the rounding error would be only 3
km, which, for a total distance of 4320 km, would corre-
spond to 0.7‰.
8. Operating examples :
8.1 Weight measurement with totaling
A throughput measurement is to be used to define the
quantity of granulate. The measuring sensor delivers 20
mA at full throughput (= 10 kg/second).
The measuring range selected will be the one ranging
from 0 to 20 mA. Allocate 0 to the lowest input signal,
10 to the highest input signal. To display the added val-
ue in tons, set the factor to 0.001.
Attention: the decimal point is only used for displaying
purposes. With a momentary value display of 10.0, the
value 100 would be added in the adding counter! This
point is to be considered accordingly when setting the
factor.
If the momentary throughput is to be displayed with one
decimal, the factor is to be set to 0.0001.
The values displayed can be shifted freely within the
display range
A reversed allocation of the value to be displayed to the
signal allows to program also descending operating
curves. In this case, the device does not display the fill-
ing level any more, but the quantity removed.
