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14.1.2 Offset and Slope

Index: 1

The T7 AIN extended feature system can automatically add a slope and a offset to analog readings, the results of which can be read through the AIN EF registers.

Configuration Registers:
CONFIG_D: Custom slope to be applied to the analog voltage reading. Default is 1.00.
CONFIG_E: Custom Offset to be applied to the analog voltage reading. Default is 0.00.

Result Registers:

READ_A: returns measured volts * slope + offset.

First write some values to configure the AIN-EF for AIN3:

AIN3_EF_INDEX = 1                // feature index for Offset and Slope.
AIN3_EF_CONFIG_D = 2.0         // slope
AIN3_EF_CONFIG_E = -0.5         // offset

Now each read of AIN3_EF_READ_A will cause a new measurement to happen and return (2.0 * volts) - 0.5.



Please specify range for slope and offet. I seem to have a problem with negative offsets.

Can this EF be used to convert LM34CAZ (10mV per Fahrenheit) readings into Centigrade values?

Any 32-bit float should be fine, but I just tested (easy to do on Analog Inputs tab of Kipling3) and get an Invalid Value error when I try to write a negative offset.  We will follow up. 

I tested using eWriteName and eReadName in LabVIEW and negative offset works fine, so perhaps a problem in Kipling3.  We will follow up.

Kipling3 (version 3.0.2) is now updated to work with negative slopes and offsets.

Edit: Added version.


Thank you very much for this immediate response.

Not just a reply, but also a bug-fix in less than 24 hrs!

Greetings from Germany,