S7 PLC read clock SFC1

[ISL_MAN]

I'm trying to get my HMI's (TP170A) clock to sync with my S7 300 PLCS clock. I've tried using SFC1 in OB1 to read the PLC clock into a DB but its doesn't seem to be working. When I monitor the DB in data view the value isn't updating. The CDT of CFC1 goes to a DATE_AND_TIME type which starts at db18.dbw2 for 8 bytes. Is this correct the help is a bit vage.

 

[SimonGoldsworthy]

Try monitoring the date and time as bytes in a VAT table to see if it realy is not working.

 

[RMA]

Why not make your life easier and read the time out of the Temp variables in OB1. The Bytes are ordered Year, Month, Day, Hour, Minute, Second starting at LB12. Saves mucking about with SFC1.