Siemens Simatic SM331, Getting Started

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Appendix
A.1 Source of the user program
SM331; AI 8x12 Bit Getting Started part 1: 4 -20mA
A-2
Getting Started, 11/2006, A5E00253410-02
END_DATA_BLOCK
FUNCTION FC 1 : VOID
TITLE =Conversion of a channel’s raw values in mA
VERSION : 1.0
VAR_INPUT
Raw : WORD ; // Analog value display
END_VAR
VAR_OUTPUT
Current : REAL ; // Current in mA
END_VAR
VAR_TEMP
TDoubleInt : DINT ;
TInt : INT;
END_VAR
BEGIN
NETWORK
TITLE = Conversion of raw values in mA
L #Raw;
T #TInt;
// Only long integers can be converted into REAL format
L
ITD
T
#TInt;
;
#TDoubleInt;
// HEX value
// Current = ---------------
L
DTR
T
#TDoubleInt;
;
#Current;
// 1728
// ! /
// ! /
// ! /
// ------- +----- /------ +----
L
/R
T
1.003;
;
#Current;
// 4 20
L
+R
T
4.000;
;
#Current;
// Offset correction
END_FUNCTION
ORGANIZATION_BLOCK OB 1
TITLE = "Main Program Sweep (Cycle)"
VERSION : 1.0
VAR_TEMP
OB1_EV_CLASS : BYTE ; //Bits 0-3 = 1 (Coming event),
Bits 4-7 = 1 (Event class 1)
OB1_SCAN_1 : BYTE ; //1 (Cold restart scan 1 of OB 1),
3 (Scan 2-n of OB 1)
OB1_PRIORITY : BYTE ; //Priority of OB Execution
OB1_OB_NUMBR : BYTE ; //1 (Organization block 1, OB1)
OB1_RESERVED_1 : BYTE ; //Reserved for system
OB1_RESERVED_2 : BYTE ; //Reserved for system
OB1_PREV_CYCLE : INT; //Cycle time of previous OB1 scan (milliseconds)
OB1_MIN_CYCLE : INT; //Minimum cycle time of OB1 (milliseconds)
OB1_MAX_CYCLE : INT; //Minimum cycle time of OB1 (milliseconds)
OB1_DATE_TIME : DATE_AND_TIME ; //Date and time OB1 started