5
36
5- Sensors and actuators
5�4 Analog sensors
Analog sensors supply an output signal either as a voltage or as a current. The WMPro has four
inputs for each type. The conguration process is the same for both types – you will need to enter a
scale factor and an oset that converts volts or mA into the relevant unit.
You can usually nd these details printed in the sensor documentation, but if not, you can easily
work them out. This is what the elds on the right are for.
Sensor type a Comments
Pt1000 IEC751 0.00385 IEC751 is an international standard governing
Pt1000 sensor calibration. It is based on a DIN
standard and is used throughout Europe.
Pt1000 JIS C1604 0.003916 JIS C1604 is a Japanese industrial standard. There
is also a corresponding US standard. Used in Japan
and some US companies.
Ni1000 DIN 0.00672 Ni1000 calibrated according to German industrial
standards.
Ni1000 LG 0.00672 Landis & Gyr have their own sensor type, which is
basically an Ni700 in series with 300 ohm.
Ni-Fe 1000 0.00518 Nickel-iron sensors usually have this alpha value.
Mo1000 0.00300 Molybdenum sensor.
Cu1000 0.00427 Copper wire sensor element.
Assume you want to measure a water level with a pressure sensor that outputs a signal between 0
and 10 volts. You can use a ruler to measure the water level, then click Measure button to tell the
WMPro to obtain a voltage reading. You need to take readings at two levels, for example 12 and
107 cm. Enter these levels and the voltage values, 1.2 V and 8.8 V, then click the left arrow. The scale
factor and the oset are calculated automatically. You can also enter values in the scale factor and
oset elds, then click the right arrow to see the values for particular voltages.
Do not forget to save the settings.
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