Siemens SIMATIC S5-100U System Manual page 350

Connecting the S5-100U to SINEC L1
STL
C DB3
A F100.7
JC =M001
L DR0
L KF+0
><F
JC =M002
L DL1
T QB0
L DR1
T QB1
L DL2
T QB2
M2: AN M100.7
S F100.7
M1: A F101.7
JC =M003
C DB2
L KF+3
T DL0
L KF+0
T DR0
L IB3
T DL1
L IB4
T DR1
L IB5
T DL2
AN F101.7
S F101.7
M3: NOP 0
BE
Figure 13-9. Programming "Message Processing" in FB2
13-12
Receive mailbox (DB3)
Check whether access to receive mailbox is permissible.
KBE/Bit 7=0: Access permitted
KBE/Bit 7=1: Access not permitted
Skip receive mailbox evaluation if access not permitted
Check whether the number of the source (master 0) is in
byte 2 of the receive mailbox
Skip receive mailbox evaluation if source No. 0
Transfer receive mailbox
to the PIQ
Set KBE/Bit 7=1, i.e. permit PLC access.
Program access is not permitted again until the
PLC has reset this bit.
Check whether access to the send mailbox is permitted.
KBS/Bit 7=0: Access permitted
KBS/Bit 7=1: Access not permitted
Skip send mailbox evaluation if access not permitted.
Set send mail box (DB2)
Specify length of the data packet in byte 1
of the send mailbox
Load destination number 0 (master) into byte 2 of the
send mailbox
Load input bytes 3, 4 and 5
into the send mailbox
Set KBS/bit 7, i.e. programmable controller has access to the send
mailbox
Explanation
EWA 4NEB 812 6120-02b
S5-100U