Technical data

Table Of Contents
System Software for S7-300/400 System and Standard Functions - Volume 1/2
A5E00709327-01
13-1
13 SFCs for Diagnostics
13.1 System Diagnostics
The CPUs maintain internal data about the status of the programmable logic
controller. With the system diagnostics functions, you can read out the most
important data. Some of the data can be displayed on the programming device
using STEP 7.
You can also access the data required for system diagnostics in your program, by
using the SFCs "RD_SINFO" and "RDSYSST."
13.2 Reading OB Start Information with SFC 6 "RD_SINFO"
Description
With SFC 6 "RD_SINFO" (read start information), you can read the start
information about the following:
The last OB to be called that has not yet been completely executed
and
The last startup OB to be started.
There is no time stamp in either case. If the call is in OB 100 or OB 101 or OB 102,
two identical start information messages are returned.
Parameter Declaration Data Type Memory Area Description
RET_VAL OUTPUT INT I, Q, M, D, L Error information
TOP_SI OUTPUT STRUCT D, L Start information of the current OB
START_UP_SI OUTPUT STRUCT D, L Start information of the startup OB
last started