Hydro Logger H40
User manual
18
electronics for ecology
FIEDLER
3.5.2.
Power supply for connected sensors and transducers
In addition to the inputs, the K2 connector contains tubes for powering connected probes
and sensors. The +Unap supply voltage (pin 1) is only briefly switched on during the
measurement period. The measurement interval is an adjustable parameter ranging from
1 min to 24 h.
Another adjustable parameter of the unit allows you to switch on this power supply in
advance of the actual measurement, so that the connected sensor can correctly adjust
the size of the output signal in proportion to the physical quantity being monitored.
The +Unap supply voltage is user adjustable from 6 to 15 V and its optimum setting
depends on the type of sensor or probe connected. A lower voltage setting saves the
lifetime of the power supply battery.
3.5.3.
Analog input AV1
Input AV1 (pin 2 on connector K2) is used to connect sensors and transducers with
output signals of 4 - 20 mA, 0 - 20 mA, 1 - 5 mA, 0 - 5 mA and 0 - 1 mA.
The voltage drop across the AV input can be as low as 2 V at 20 mA. This drop should
be increased by the minimum supply voltage of the connected sensor declared by its
manufacturer on the +Unap power terminal. Conversely, an unnecessarily high +Unap
supply voltage will excessively deplete the capacity of the power supply battery.
The analog signal supplied to the AV1 input is measured by a precision transducer with
a digital filter that suppresses the interference voltage induced in the input cable and
performs automatic self-calibration of the set measuring range.
The measuring sensor can be connected to the AV1 input in both two-wire (pins: +Unap,
AV1) and three-wire (pins: +Unap, AV1, GND).
3.5.4.
RS485 serial line
The RS485 communication bus is designed for connection of selected sensors and
measuring transmitters that communicate under FINET, HART or Modbus RTU proto-
cols. Such devices can be, for example, ultrasonic or submersible level sensors US1200
and TSH22, water conductivity sensors ESV11 and many other sensors and transducers
listed in the table on page 28.
When setting the parameters of the selected recording channel, it is necessary to enter
the communication address of the connected probe or sensor and the number of the
internal channel in the connected measuring probe (details about the types of sensors
and their settings can be found in chapter 4.3.1.).
+ U n a p
C o n n e c t i o n o f
L M P 8 5 8 l e v e l
s e n s o r w i t h 4 - 2 0 m A
o u t p u t
T E P 0 6 t r a n s m i t t e r
c o n n e c t i o n
