CAN-CBX-AI420 - esd electronics, Inc.

Device Profile Area
Calculation of the measured values:
The relationship of the objects is described in the figure on page 63. The single steps for the calculation
of the A/D-value, returned in the objects 6401 h, and 6402 h are described in the following.
Firmware-internal variables (can not be read by the user):
AD-value ............measured values of the A/D-converter without correction
Ana_In_16_og_x ......A/D-value corrected with Offset and Gain
Ana_In_16_accu_x ....A/D-value resulting from addition of n A/D-values
x ...................number of the A/D-channel (1, 2, 3, 4)
Variables accessible via CANopen-objects:
Gain_x ....................Gain-factor (object 2405 h, see page 79), default: Gain = 1
Offset_x ...................Offset-value (object 2404 h, see page 78), default: Offset = 0
n .........................Number of additions (object 2402 h, see page 76), default n = 1 (no additions)
m .........................Number of the averaged values (object 2403 h, see page 77),
default: m = 32 (moving average from 32 A/D-values)
Read_Analogue_Input_16_x . . A/D-converter value, which has been calculated of m A/D-values (which has already
been corrected by gain, offset and addition) by the moving average method
(object 6401 h, 6402 h).
Steps of calculation:
1. Correction with gain-factor and offset-value:
2. Addition of the measured values:
Ana_In_16_og_x = Offset_x + (AD-value Gain_x)
Ana_In_16_accu_x = Ana_In_16_og_x (1) + Ana_In_16_og_x (2) + ... + Ana_In_16_og_x (n)
3. Calculation of the moving average:
Ana_In_16_accu_x (1) + Ana_In_16_accu_x (2) + ... + Ana_In_16_accu_x (m)
Read_Analogue_Input_16_x = ------------------------------------------------------------------------------------------------n
m
CAN-CBX-AI420 Manual Rev. 1.3 65