Data stream and correction calculation

Data stream

The following flow chart illustrates the data stream of the EPI3174, ERI3174 (processing of raw data).

Data stream and correction calculation 1:

Correction calculation

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)

Data stream and correction calculation 2:
Data flow with correction calculation for +/- 10 V or +/- 10 mA

(0…20 mA)

Data stream and correction calculation 3:
Data flow with correction calculation for 0…20 mA

(4…20 mA)

Data stream and correction calculation 4:
Data flow with correction calculation for 4…20 mA

(0…10 V)

Data stream and correction calculation 5:
Data flow with correction calculation for 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

User calibration, index 0x08n0:0A

The user calibration is enabled via index 0x80n0:0A. Parameterization takes place via the indices

User scaling, index 0x08n0:01

User scaling is enabled via index 0x08n0:01. Parameterization takes place via the indices

Data stream and correction calculation 6:

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

-