FB_DBRecordArraySelect

VAR_INPUT

VAR_INPUT
    sNetID           : T_AmsNetID;
    hDBID            : UDINT;
    cbCmdSize        : UDINT;
    pCmdAddr         : UDINT;
    nStartIndex      : UDINT;
    nRecordCount     : UDINT;
    cbRecordArraySize: UDINT;
    pDestAddr        : POINTER TO BYTE;
    bExecute         : BOOL;
    tTimeout         : TIME;
END_VAR 

sNetID: String containing the AMS network ID of the target device, at which the ADS command is directed.

hDBID: Indicates the ID of the database to be used.

cbCmdSize: Indicates the length of a SELECT command to be executed.

pCmdSize: Indicates the pointer address of a string variable with the SQL command to be executed.

nStartIndex: Indicates the index of the first record to be read.

nRecordCount: Indicates the number of records to be read.

cbRecordArraySize: Indicates the size of the structure array in bytes.

pDestAddr: Indicates the address of the structure array into which the records are to be written.

bExecute: The command is executed with a rising edge.

tTimeout: Indicates the time before the function is cancelled.

VAR_OUTPUT

VAR_OUTPUT
    bBusy    : BOOL;
    bError   : BOOL;
    nErrID   : UDINT;
    sSQLState: ST_DBSQLError;
    nRecords : UDINT;
END_VAR 

ST_DBSQLError

bBusy: The command is in the process of being transmitted by ADS. No new command will be accepted as long as bBusy remains TRUE.

bError: Becomes TRUE, as soon as an error occurs.

nErrID: Returns the ADS error code or TcDatabaseSrv_Error_Codes if the bError output is set.

sSQLState: Returns the SQL error code of the corresponding database type

nRecords: Returns the number of data records.

Sample in ST

Since the table, from which the records are to be read, has the structure below, a PLC structure with a similar structure must be created.

Table:

Structure:

TYPE ST_Record:
STRUCT
    ID       : T_ULARGE_INTEGER;
    Timestamp: DT;
    Name     : STRING(80);
    VALUE    : LREAL;
END_STRUCT
END_TYPE 

The library TcUtilities.lib must be integrated in order to be able to use the data type T_ULARGE_INTEGER.

For ARM processors the data types have to be arranged differently due to the byte alignment, and a "dummy byte" has to be added.

TYPE ST_Record :
STRUCT
    ID       : T_ULARGE_INTEGER;
    Timestamp: DT;
    Value    : LREAL;
    Name     : STRING(80);
    Dummy    : BYTE;
END_STRUCT
END_TYPE 

PROGRAM MAIN
VAR
    FB_DBRecordArraySelect1 : FB_DBRecordArraySelect;
    cmd         : T_Maxstring := 'SELECT * FROM myTable';
    (* Unter ARM*) 
    (*cmd       : T_Maxstring := 'SELECT ID,Timestamp,Value,Name FROM myTable'*)
    (*----------*)
    recordArray : ARRAY [1..5] OF ST_Record;
    busy        : BOOL;
    err         : BOOL;
    errid       : UDINT;
    sqlstate    : ST_DBSQLError;
    recAnz      : UDINT;
END_VAR 

PLC program

FB_DBRecordArraySelect1(
    sNetID:= ,
    hDBID:= 1,
    cbCmdSize:= SIZEOF(cmd),
    pCmdAddr:= ADR(cmd),
    nStartIndex:= 0,
    nRecordCount:= 5,
    cbRecordArraySize:= SIZEOF(recordArray),
    pDestAddr:= ADR(recordArray),
    bExecute:= TRUE,
    tTimeout:= T#15s,
    bBusy=> busy,
    bError=> err,
    nErrID=> errid,
    sSQLState=> sqlstate,
    nRecords=> recAnz);

Requirements