Siemens SIMATIC S5 Manual page 257

D 2.2: start bit, read actual value channel 14.
By setting this bit, you trigger the reading of the actual value on channel 14.
FB 162 resets the bit immediately after the command has been transferred to the
module. You can set the bit again at any time, even if the last job is not yet
complete. The last job triggered is always valid.
D 2.3: acknowledgement bit, read actual value channel 14.
This bit is set by FB 162 when the read function is complete and the value is stored
in DB-B: the bit remains set until a new read job is triggered.
D 2.4: free
D 2.5: free
D 2.5: free
D 2.7: end of the machine cycle (only for cascaded control).
By setting this bit, you indicate the end of a machine cycle. The bit is reset by the
function block.
IP244
C79000–B8576–C861–02
Application of the Function Block
5–53