S7 300 PLC real time clock time

Further to a post yesterday regarding access to the PLC's real time clock in an S7 300 PLC, I have followed the advice of the forum and used the SFC1 and put the results into A vat table. The time of day comes back, but in a HEX BYTE as per the picture attached. How can I convert this number to an integer for example for use in a comparison with an HMI operator entered value?

Use the BTI instruction to convert each entry from BCD to integer. Do you need the millisecs and day of the week ?

Here is code provided by user GeneInc from december 2009; it uses the BTI instruction in STL:


Here is my code. This takes the current date and tme and puts it into individual integers. You can create a FC with this (hence the # before the variable) or just make it a rung in your program.

CALL SFC 1 //Get Date and Time
RET_VAL:=#RetVal
OUT0 :=#Out_Time_Date //Date and Time

//Extract Year
L LB 2 //Load Byte 2
BTI //Convert To Integer
T #int_Year //Store in Variable
//Extract Month
L LB 3
BTI //Convert To Integer
T #int_Month
//Extract Day
L LB 4
BTI //Convert To Integer
T #int_Day
//Extract Hour
L LB 5
BTI //Convert To Integer
T #int_Hour
//Extract Minute
L LB 6
BTI //Convert To Integer
T #int_Minute
//Extract Second
L LB 7
BTI //Convert To Integer
T #int_Second

Hope this helps,
Daniel Chartier

Reviving thread as I'm having trouble using the real time clock. I'm trying to keep a runtime count of a process and reset this every 6AM and 6PM. Here is my code (took from another thread):

CALL "READ_CLK" //Call SFC 1, "Read System Clock"
RET_VAL:=#Return
CDT :=#ReadCurrentTime


//***************************
//Load each byte of #ReadCurrentTime and transfer
//them to data bytes. This wouldn't be
//absolutely necessary, but it's nice to go online
//with the block and see what the current time is.
//Use the Siemens Help to see the "Date and Time"
//format to see why I have to SLW12 and SRW12 on LB7.
//***************************
L LB 0
T "Daily Reset DB".Year
L LB 1
T "Daily Reset DB".Month
L LB 2
T "Daily Reset DB".Day
L LB 3
T "Daily Reset DB".Hour
L LB 4
T "Daily Reset DB".Minute
L LB 5
T "Daily Reset DB".Second
L LB 6
T "Daily Reset DB".MillisecMSB
L LB 7
SLW 12
SRW 12
T "Daily Reset DB".DayofWeek


//***************************
//Siemens uses the BCD format in the Date And Time,
//so I have to use the BTI instruction to convert
//it to an integer. In this section, I check to see
//if it is 600 hours (6AM) OR 1800 hours (6PM) . If it is not, then I don't jump
//to label "rst", and I end the block.
//***************************

O(L "Daily Reset DB".Hour
BTI
L 6
==I)
O(L "Daily Reset DB".Hour
BTI
L 18
==I)
AN "Daily Reset DB".ResetComplete
JC rst
BEU


//***************************
//If it has reached 6AM or 6PM, I jump to
//"rst", transfer my runtime values to historian, then transfer
//a zero to the runtime variables. I also set the "ResetComplete" bit
//as a way to create a one-shot (see the comparison
//above) so this is only executed once.
//***************************

rst: L "RUNTIME”.Hours
T "Hist_Real”.Hours
L "RUNTIME”.Minutes
T "Hist_Real”.Minutes
L 0
T "RUNTIME”.Hour
T "RUNTIME”.Minutes
SET
= "Daily Reset DB".ResetComplete



- In the OR statements I'm getting a syntax error at "Daily Reset DB"
- At the rst statement I'm getting S identifier goes beyond end of row?

EDIT: I just realized for the OR statements I will need to use not only hours but minutes and seconds if I only want to reset right at 6:00:00AM and 6:00:00. Doing AND/OR is confusing to me in STL so any help would be appreciated.

Here's an example project using a different approach to solving your problem. It is based on three shifts but you can ignore the third shift. FC8 is from the Siemens library.