TwinCAT Systemtime-Timestruct to milliseconds since epoch

Question

I need to convert the timestruct I get from Beckhoffs function block "FB_LocalSystemTime" to milliseconds since epoch to receive the local computer time in milliseconds.

Unfortunately I can't find a function to convert this timestruct. Any help is appreciated.

//Local Systemtime variables
fbTime : FB_LocalSystemTime := ( bEnable := TRUE, dwCycle := 1 );

Answer 1

You can use the SYSTEMTIME_TO_DT() function to convert a timestruct to dt which is a 4byte DATE_AND_TIME data type.

The smallest unit of this data type is a second though and not a millisecond. Given that TIMESTRUCT has a millisecond value in it, you can easily use it and concatenate everything to a human readable string.

Answer 2

I think you can use DT_TO_DINT after converting the TIMESTRUCT to DT. This should give you seconds since Jan 1, 1970.

EDIT: This code should give you milliseconds since 1/1/1970.

PROGRAM MAIN
VAR
    fbTime: FB_LocalSystemTime;
    tStruct: TIMESTRUCT;
    msec: DINT;
    dTime: DATE_AND_TIME;
    eTime_sec: DINT;
    eTime_msec: LINT;
END_VAR

fbTime(bEnable:=TRUE, dwCycle:=1, SystemTime=>tStruct);

msec := tStruct.wMilliseconds;
tStruct.wMilliseconds := 0;

dTime := SYSTEMTIME_TO_DT(tStruct);
eTime_sec := DT_TO_DINT(dTime);
eTime_msec := DINT_TO_LINT(eTime_sec) * 1000 + msec;

Answer 3

You will get miliseconds with this function:

FUNCTION F_SYSTEMTIME_TO_TIMESTRUCT : TIMESTRUCT
VAR
    fbGetSystemTime : GETSYSTEMTIME;    (*timestamp*)
    fileTime        : T_FILETIME;
    sDT: STRING(30);
END_VAR

fbGetSystemTime(timeLoDW => fileTime.dwLowDateTime, timeHiDW => fileTime.dwHighDateTime);
sDT := SYSTEMTIME_TO_STRING(FILETIME_TO_SYSTEMTIME(fileTime));

F_SYSTEMTIME_TO_TIMESTRUCT.wYear := STRING_TO_WORD(LEFT(sDt, 4));
F_SYSTEMTIME_TO_TIMESTRUCT.wMonth := STRING_TO_WORD(MID(sDt, 2, 6));
F_SYSTEMTIME_TO_TIMESTRUCT.wDay := STRING_TO_WORD(MID(sDt, 2, 9));
F_SYSTEMTIME_TO_TIMESTRUCT.wHour := STRING_TO_WORD(MID(sDt, 2, 12));
F_SYSTEMTIME_TO_TIMESTRUCT.wMinute := STRING_TO_WORD(MID(sDt, 2, 15));
F_SYSTEMTIME_TO_TIMESTRUCT.wSecond := STRING_TO_WORD(MID(sDt, 2, 18));
F_SYSTEMTIME_TO_TIMESTRUCT.wMilliseconds := STRING_TO_WORD(RIGHT(sDt, 3));

Answer 4

I've used function GetSystemTime() which returns number of 100ns since 1 January 1601 (god knows why). So we just need to shift up to 1/1/1970 by add 11644473600_000_000_0 (which is amount od 100ns periods between dates) and then convert 100ns periods to e.g. miliseconds by divide over 1000_0 or seconds by divide them over 1_000_000_0. Remember that's a UTC time, if You want to get local time use FB_LocalSystemTime and timestruct conversion as @kolyur mentioned.

FUNCTION GET_UNIX_EPOCH : ULINT

GET_UNIX_EPOCH := (F_GetSystemTime() - 116444736000000000) / 10000;