Using the ”SEND” and ”Receive” Function Blocks
CP 523
8.1.3
Structure of the Status Byte
The status bytes of "SEND" FB 200 and "RECEIVE" FB 201 are identical. The status byte gives
information on whether
•
Receive data is available (bit 0 = 1)
•
The Send mailbox is empty (bit 1 = 1)
If the Send mailbox is occupied, the Send job initiated by calling "SEND" FB 200 can not be
executed.
•
Errors have occurred (bit 3 = 1)
If bit 3 is set, bits 4 to 7 contain the error code.
1 Receive data
available
0 No receive data
available
1 Permission to send
0 No permission to send
1 Bits 4 to 7 contain error
code
0 No errors
Status byte
a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a
a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a
a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a
a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a
a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a
a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a
a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a
SEND FB
Parameter error
RECEIVE FB
Parameter error
Target DB too
small for
Receive data
Error flagged in
the CBS
0
0
0
1
0
1
1
0
1
0
0
0
1
0
1
0
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Figure 8-1. Structure of the "STAT" Status Byte
8-4
EWA 4NEB 811 6044-02a