HYDAC AS 1000 - Manual (Page 4)

User Manual AS 1000 09.04.2008
4
4. Function
The Aqua Sensors in the series AS 1000 are water and temperature sensors for the continuous
and accurate online monitoring of hydraulic and lubrication fluids.
They measure the water content relative to the saturation concentration (saturation point) and read
out the degree of saturation in the range 0..100% as a 4..20mA analogue signal. A reading of 0%
would indicate a fluid free of water, whilst 100% would indicate a fluid that is saturated with water.
The capacitance sensor used in the AS 1000 absorbs water molecules from the fluid which results
in a change in capacitance of the sensor element. The measured value obtained represents the
level of saturation of the fluid in percent.
A thermal element on the sensor measures the temperature in the range
-25 ... +100°C. This is read out as a 4...20mA analogue signal, like the saturation level.
Outputs 1 and 2 can be configured independently of each other as switch or analogue outputs.
4.1 Switching output
With switching output 1 or switching output 2 the following variables can be monitored within
their limits:
Saturation level:
0 % ... 100 %
Temperature: -25 °C ... +100 °C
"Switch on point" is used to indicate the value at which the output switches when the pre-set
value is exceeded.
"Switch off point" is used to indicate the value at which the output switches back when the
value falls below its pre-set level.
"Switching direction" is used to determine whether the output, when exceeding the pre-set
value, switches:
a) from GND to U
b
(N/O function)
b) from U
b
to GND (N/C function)
4.2 Analogue output
With analogue output 1 or analogue output 2 the following variables can be displayed within
their limits:
Saturation level:
0 % ... 100 %
Temperature: -25 °C ... +100 °C
The outputs are always configured as current outputs (4 ... 20 mA).