Siemens SIMATIC S5 Manual page 324

STEP 5 Programming
When a job request is allowed and the output frame has been programmed, the
start command must be loaded into QB 65 and the TOGGLE bit inverted.
START
Reset flag 3.0 and
command flag FY6
Was the last
no
direction FWD?
yes
Bit 3 is set to "1"
in FY 6
("Rev" command)
yes
Was TOGGLE
= "1" ?
no
Bit 7 is set to "1"
in FY 6.
FY 6 is loaded into
QB 65.
END
9-36
FB 13 - NAME:TOGGLE
Inverting the direction of travel in depen-
dence on the last traversing operation.
Bit 2 is set to "1"
Inverting the TOGGLE bit and transferring
in FY 6
("Fwd" command)
the command byte to the output frame.
CONT:
Bit 7 is set to "0"
INVT:
in FY 6.
FY 6 is loaded into
QB 65.
IP 266
A F 3.0
R F 3.0
L KH 0
T FY 6
A Q 65.2
S F 6.3
JC = CONT
S F 6.2
A Q 65.7
JC = INVT
L FY 6
L KH 0080
OW
T QB 65
BEU
L FY 6
L KH 007F
AW
T QB 65
BE
EWA 4NEB 812 6057-02