Calib_Step2_CalculateStoreParameters

Overview

The Calib_Step2_CalculateStoreParameters function block performs the second step of the AI module calibration procedure. This step calculates and stores calibration parameters for the selected channel, based on PLC AI module values at multiple input levels (0%, 25%, 50%, 75%, 100%).

Module_ID                       :=  (USINT)
Channel_Number                  :=  (USINT)
Channel_Mode                    :=  (BOOL)
Measured_0_percent              :=  (UINT)
Measured_25_percent             :=  (UINT)
Measured_50_percent             :=  (UINT)
Measured_75_percent             :=  (UINT)
Measured_100_percent            :=  (UINT)
CMD_Calculate_Store_Parameters  :=  (BOOL)
STS_Done                        =>  (BOOL)
STS_Failed                      =>  (BOOL)
STS_Fault_Code                  =>  (USINT)

Interface

Inputs

Name	Type	Range / Units	Description
Module_ID	USINT	1 - 15	Unique identifier of the AI module.
Channel_Number	USINT	0 - 3	Target AI channel for calibration.
Channel_Mode	BOOL	0 / 1	Channel mode for which the calculation is done: `1` = 0-10 V `0` = 4-20 mA.
Measured_0_percent	UINT	0 - 999 mV 3001 - 4999 µA	Measured value at 0% input.
Measured_25_percent	UINT	1501 - 3499 mV 7001 - 8999 µA	Measured value at 25% input.
Measured_50_percent	UINT	4001 - 5999 mV 11001 - 12999 µA	Measured value at 50% input.
Measured_75_percent	UINT	6501 - 8499 mV 15001 - 16999 µA	Measured value at 75% input.
Measured_100_percent	UINT	9001 - 10999 mV 19001 - 20999 µA	Measured value at 100% input.
CMD_Calculate_Store_Parameters	BOOL	TRUE / FALSE	Execute on a rising edge (input goes from `FALSE` to `TRUE`).

⚠️ Valid range

Measured values must be within ±999 of the nominal target for the selected channel mode.
If a Measured_xx_percent value is outside the valid range, the FB will set STS_Failed = TRUE and provide the corresponding STS_Fault_Code.

Outputs

Name	Type	Description
STS_Done	BOOL	`TRUE` if the calculation and storage of calibration parameters is successfully completed.
STS_Failed	BOOL	`TRUE` if the operation failed.
STS_Fault_Code	USINT	Diagnostic code indicating the reason for failure.

Fault Codes

Code	Meaning	Description
92	Step2 Calculate/Store Failed	Calculation or storage of parameters failed.
97	Module Faulted	The AI module reported an internal fault.
98	Module Mismatch	The detected module type does not match the expected AI module.
99	Module Not Found	The specified `Module_ID` is not part of the current hardware configuration.

Example

PROGRAM PROG_AI_Calib_Step2_CalculateStoreParameters
    VAR
        AI_Calib_Step2 : Calib_Step2_CalculateStoreParameters;
        Trigger_Tag    : BOOL := FALSE; (* Toggling trigger for repeated scans *)
        _Measured_0_percent : UINT;
        _Measured_25_percent : UINT;
        _Measured_50_percent : UINT;
        _Measured_75_percent : UINT;
        _Measured_100_percent : UINT;
    END_VAR

    (* Call FB with the toggling tag as the command *)
    AI_Calib_Step2(
        Module_ID := 4,
        Channel_Number := 0,           (* Channel 0 *)
        Channel_Mode := 0,             (* 4-20mA mode *)
        Measured_0_percent := _Measured_0_percent,
        Measured_25_percent := _Measured_25_percent,
        Measured_50_percent := _Measured_50_percent,
        Measured_75_percent := _Measured_75_percent,
        Measured_100_percent := _Measured_100_percent,
        CMD_Calculate_Store_Parameters := Trigger_Tag
    );
END_PROGRAM

CONFIGURATION Config0
    RESOURCE Res0 ON PLC
        TASK task1_20ms(INTERVAL := T#20ms, PRIORITY := 1);
        PROGRAM Prog_Instance WITH task1_20ms : PROG_AI_Calib_Step2_CalculateStoreParameters;
    END_RESOURCE
END_CONFIGURATION