Get_AI_Data

Overview

The Get_AI_Data function block retrieves the analog values for the AI module’s input channels. Each of the eight channels can be configured for either voltage or current input.

Module_ID           :=  (USINT)
Ch0                 :=  (UINT)
Ch1                 :=  (UINT)
Ch2                 :=  (UINT)
Ch3                 :=  (UINT)
Ch4                 :=  (UINT)
Ch5                 :=  (UINT)
Ch6                 :=  (UINT)
Ch7                 :=  (UINT)
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.
Ch0	UINT	4,000 - 20,000 µA 0 - 10,000 mV	Input for channel 0.
Ch1	UINT	4,000 - 20,000 µA 0 - 10,000 mV	Input for channel 1.
Ch2	UINT	4,000 - 20,000 µA 0 - 10,000 mV	Input for channel 2.
Ch3	UINT	4,000 - 20,000 µA 0 - 10,000 mV	Input for channel 3.
Ch4	UINT	4,000 - 20,000 µA 0 - 10,000 mV	Input for channel 4.
Ch5	UINT	4,000 - 20,000 µA 0 - 10,000 mV	Input for channel 5.
Ch6	UINT	4,000 - 20,000 µA 0 - 10,000 mV	Input for channel 6.
Ch7	UINT	4,000 - 20,000 µA 0 - 10,000 mV	Input for channel 7.

Outputs

Name	Type	Description
STS_Done	BOOL	TRUE when all AI data has been successfully retrieved from the module.
STS_Failed	BOOL	TRUE if the AI data read operation failed.
STS_Fault_Code	USINT	Diagnostic code indicating the reason for failure.

Fault Codes

Code	Meaning	Description
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:

(* Define custom data type *)
TYPE
  AI_8CH : STRUCT
    Ch0 : UINT;
    Ch1 : UINT;
    Ch2 : UINT;
    Ch3 : UINT;
    Ch4 : UINT;
    Ch5 : UINT;
    Ch6 : UINT;
    Ch7 : UINT;
  END_STRUCT;
END_TYPE


PROGRAM PROG_Read_AI
  VAR_EXTERNAL
    Module4_AI : AI_8CH;
    Module4_AI_Done   : BOOL;
    Module4_AI_Failed : BOOL;
    Module4_AI_Fault  : USINT;
  END_VAR
  VAR
    AI_Mode_Block : Set_AI_Mode;
    AI_Read_Instance : Get_AI_Data;
  END_VAR

    AI_Mode_Block(
        Module_ID := 4,
        Ch0_Mode := TRUE,       (* 0–10V *) 
        Ch1_Mode := TRUE,       (* 0–10V *)
        Ch2_Mode := FALSE,      (* 4–20mA *) 
        Ch3_Mode := FALSE,      (* 4–20mA *)
        Ch4_Mode := FALSE,      (* 4–20mA *)
        Ch5_Mode := FALSE,      (* 4–20mA *)
        Ch6_Mode := FALSE,      (* 4–20mA *)
        Ch7_Mode := FALSE       (* 4–20mA *)
        );
        
  (* Read from Module 4 *)
  AI_Read_Instance(Module_ID := 4);

  (* Map function block outputs to global structure *)
  Module4_AI.Ch0 := AI_Read_Instance.Ch0;
  Module4_AI.Ch1 := AI_Read_Instance.Ch1;
  Module4_AI.Ch2 := AI_Read_Instance.Ch2;
  Module4_AI.Ch3 := AI_Read_Instance.Ch3;
  Module4_AI.Ch4 := AI_Read_Instance.Ch4;
  Module4_AI.Ch5 := AI_Read_Instance.Ch5;
  Module4_AI.Ch6 := AI_Read_Instance.Ch6;
  Module4_AI.Ch7 := AI_Read_Instance.Ch7;

  (* Optional: expose status to globals for diagnostics *)
  Module4_AI_Done   := AI_Read_Instance.STS_Done;
  Module4_AI_Failed := AI_Read_Instance.STS_Failed;
  Module4_AI_Fault  := AI_Read_Instance.STS_Fault_Code;
END_PROGRAM


CONFIGURATION Config0
  RESOURCE PLC ON PLC
    VAR_GLOBAL
      Module4_AI : AI_8CH;
      Module4_AI_Done   : BOOL;
      Module4_AI_Failed : BOOL;
      Module4_AI_Fault  : USINT;
    END_VAR
    TASK Task_50ms(INTERVAL := T#50ms, PRIORITY := 1);
    PROGRAM Read_AI WITH Task_50ms : PROG_Read_AI;
  END_RESOURCE
END_CONFIGURATION