Data stream and correction calculation
Data stream
The following flow chart illustrates the data stream of the EPI43xx (processing of raw data).
Correction calculation EPI43xx
The diagrams at the bottom show the correction calculation between the raw values and the output values if the limit ranges are exceeded.
(+/- 10 V or +/- 10 mA)
(0…20 mA)
(4…20 mA)
(0…10 V)
Calibration
Vendor calibration, index 0x08n0:0B
Vendor calibration is enabled via index 0x0800:0B, with n = 0 (ch. 1), with n = 1 (ch. 2), …n = 3 (ch. 4). Parameterization takes place via the indices
- 0x08nF:01 vendor calibration: Offset
- 0x80nF:02 vendor calibration: Gain
User calibration, index 0x08n0:0A
The user calibration is enabled via index 0x80n0:0A. Parameterization takes place via the indices
- 0x08n0:17 user calibration: Offset
- 0x08n0:18 user calibration: Gain
User scaling, index 0x08n0:01
User scaling is enabled via index 0x08n0:01. Parameterization takes place via the indices
- 0x08n0:11 user scaling: Offset
- 0x08n0:12 user scaling: Gain
Vendor calibration The vendor reserves the right to carry out the basic calibration of the terminal/box modules. Therefore, the vendor calibration cannot be changed. |
Calculation of process data
The terminal/box continuously logs measured values and stores the raw values of its A/D converter in ADC raw value object 0x08nE:01. After each logging of the analog signal a correction is calculated via the vendor calibration values. This is followed (optionally) by user scaling:
YH= (XADC-BH) * AH measured value after vendor calibration (corresponds to XADC if index 0x08n0:0B inactive)
YA= (YH-BA) * AA measured value after user calibration (corresponds to YH if index 0x08n0:0A inactive)
YS= YA * AS * 2-16 + BS measured value after user scaling (corresponds to YA if index 0x08n0:01 is inactive)
Key
Name | Designation | Index |
---|---|---|
XADC | Output value of the A/D converter | 0x8nE:01 |
BH | Vendor calibration offset (only changeable if the object Producer codeword F008 is set) | 0x08nF:01 |
AH | Vendor calibration gain (can only be changed if the object Producer codeword F008 is set) | 0x08nF:02 |
YH | Measured value after vendor calibration | - |
BA | User calibration offset | 0x08n0:17 |
AA | User calibration gain | 0x08n0:18 |
YS | Measured value after user calibration | - |
BS | User scaling offset (can be activated via index 0x80n0:01) | 0x08n0:11 |
AS | User scaling gain (can be activated via index 0x80n0:01) | 0x08n0:12 |
YS | Process data for control, measured value after user scaling | - |