Hydro Logger H40
User manual
FIEDLER
electronics for ecology
23
Very often a measuring probe or sensor is connected to the telemetry station via the
RS485 serial communication interface. With this method of communication between the
station and the sensor, it is necessary to set the communication address of the sensor
and the number of the internal measurement channel for the desired physical quantity
(see overview table on the following page) in addition to the appropriate measurement
method.
The measuring method "
Intelligent probe via RS485/HART
" is set for probes from BD
Sensors s.r.o. , equipped with RS485 interface.
The measurement method "
Intelligent probe via RS485/FINET
" is set for FIEDLER
probes and sensors equipped with RS485 interface.
Some quantities, such as pressure or flow, have a rich list of units in which the desired
quantity can be measured, archived and displayed. Other quantities, such as rainfall or
battery voltage, offer only one type of unit.
An important parameter for determining the resolution of each monitored variable is the
number of decimal places with which the measured variables are to be archived in the
selected units of measurement. A higher number of decimal places is at the expense of
the allowed range. An inappropriate choice of the number of decimal places may cause
the maximum range to be exceeded, resulting in 'clipping' of out-of-range values
.
The maximum possible magnitude that the measurand can take is 65535 for integers
and it decreases decade by decade as the number of decimal places increases. Bipolar
quantities such as temperature or voltage have half this maximum possible value. This
"limitation" results from the 16-bit archiving of measured instantaneous values.
The relationship between the number of decimal places and the allowable range of the
monitored variable can be seen in the following table.
Tab. 2: Maximum range of archived values
No of dec. Resolution Max. range of unipolar quantity Max. range of bipolar quantity
0
1
0 ... 65535
-32767 to +32767
1
0,1
0,0 .. 6553,5
-3276.7 to +3276.7
2
0,01
0,00 .. 655,35
-327.67 to +327.67
3
0,001
0,000 .. 65,535
-32.767 to +32.767
This parameter determines which terminals will be used to connect the sensor. As men-
tioned, the H40 station has one pulse input PV1 and one current analog input AV1.
If you select one of the measurement methods using the RS485 serial bus, MOST will
require the "
Address
" and "
Channel" parameters
to be set instead of the "Input" pa-
rameter.
R S 4 8 5
U n i t s
N u m b e r o f d e c i m a l
p l a c e s
A c c e s s
R S 4 8 5 - a d d r e s s a n d
c h a n n e l s e t t i n g
Communication
address of the connec-
ted device
Serial number of the
internal channel of the
connected device
Measurement method
for communication
with probes under
FINET protocol
