Halytech
hydroSpider2 User’s Manual v1.23
Page 44
5.6.6
Advanced: 2-point calibration
Applies to
: Analogue (Voltage), Analogue (4-20mA)
2-point calibration automatically determines the appropriate scaler and offset by taking two raw
readings (a low reading and a high reading) and having the user enter each reading’s associated real-
world value.
The two point calibration page will lead you through a series of steps, after which the hydroSpider
will calculate the correct offset and scalar to use based on the entered data.
For example
: a voltage pressure sensor is being used to measure the water level in a tank. An
analogue voltage channel, “Level”, is set up and configured with units of cm. 2-point calibration is
chosen from the channel’s calibration menu.
The first step in two point calibration is to generate a minimum value in the sensor. For this purpose,
the sensor immersed in 20cm of water and a reading is taken.
The desired reading is therefore entered as 20, and the raw reading is updated to show 178.
2-point calibration steps 1-3
These two values are then locked in by clicking the
Click here
button.
The next step is to generate a large value in the sensor. For this purpose, the sensor is immersed in
290cm of water and a reading is taken. The desired reading is therefore entered as 290, and the raw
reading is updated to show 3783.
2-point calibration steps 4-6
This second pair of numbers is locked in via the
Click here
button
