User manual

104 Publication LOGIX-AP010B-EN-P - May 2010
Chapter 5 Conversion of System Functions
Example: Setting the Time
The following ladder diagram shows a SSV instruction on the WallClock
object being used to set the date and time with the values stored in the
elements of the array SetDateTime[7].
SetDateTime[0] - year
SetDateTime[1] - month
SetDateTime[2] - day
SetDateTime[3] - hour
SetDateTime[4] – min
SetDateTime[5] – sec
SetDateTime[6] – microsecond
Save/Load Scratchpad Area
The S5 standard function blocks and user-generated function blocks may use
bytes FW200-FW254 to generate and store intermediate results.
FB 38 is used to save this data area if the cyclic program is interrupted by a
time/interrupt driven process.
FB 39 is called at the end of the time/event driven process and is used to
reload the values to these memory locations.
The reason for these save/load functions is that the time/event driven process
could overwrite this temporary storage area and that could result in incorrect
intermediate results being present in this area when the normal cyclic process
is resumed after a time/interrupt process has been completed.
RSLogix 5000 software does not use a shared temporary shared memory
location. Add-On Instructions can have temporary data tags but these will be
exclusive to the Add-On Instruction to which they are assigned.