Halytech
hydroSpider2 User’s Manual v1.23
Page 40
5.6
Input Channel Calibration
Calibration refers to changing the range of values which a channel produces so that it matches a
real-world value. By default, counter channels increment by 1 each count, analogue voltage channels
report a value between 0 and 4095, and analogue 4-20mA channels report a value between 4 and
20. More often than not, these are not suitable for the application at hand, and so channel
calibration is used.
Calibration of a channel is linear and makes use of a scaler and an offset. The following formula is
used for all channel calibration:
𝑣𝑎𝑙𝑢𝑒
𝑐𝑎𝑙𝑖𝑏𝑟𝑎𝑡𝑒𝑑
= (𝑣𝑎𝑙𝑢𝑒
𝑟𝑎𝑤
× 𝑠𝑐𝑎𝑙𝑒𝑟) + 𝑜𝑓𝑓𝑠𝑒𝑡
Once the channels have been set up, calibration can be accessed using the drop down on the left
hand side of the Change Setup page, shown below:
Change Setup page showing location of the channel
calibration dropdown box
This takes you to a “Channel Calibration” page, where you can select the calibration method to be
used.
There are a number of different calibration methods available in the hydroSpider2. Only those
appropriate for the input being calibrated will be listed on the “Channel Calibration” page.
They are all covered in the following sections.
