Detailed description
2.12 Block descriptions
Basic logic functions: PLC Basic program powerline (P3 pl)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0
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2. Read word of position offset 8 without semaphore and store in MW 104:
CALL FC 21 (
Enable := M 10.0, // if TRUE, FC 21 active
Funct := B#16#3, //Read data
S7Var := P#M 104.0 WORD 1,
IVAR1 := 8,
IVAR2 := -1,
Error := M 10.1,
ErrCode := MW12);
Function
5: Update control signals to channel:
The purpose of function 5 is to transmit important control signals at high speed in between
cyclic data transfers. Data bytes 6 and 7 of user interfaces DB21 to DB30 are transferred to
the NC. The channel is specified in parameter "IVAR1". This function can be used, for
example, to transfer a feed stop, read-in disable outside the PLC cycle.
The following signals are relevant:
Signal Type Type Value range Remark
Enable I BOOL 1= FC 21 active
Funct I BYTE 5 5: Control signals to channel
S7Var I ANY S7 data storage area Not used
IVAR1 I INT 1. Max. channel Channel number
Error A BOOL
ErrCode A INT 1: "Funct" invalid
10: Channel no. invalid
6: Update control signals to axes:
The purpose of function 6 is to transmit important control signals at high speed in between
cyclic data transfers. The data byte 2 of application interface DB31 to DB61 is transferred to
the NC. The transfer is performed for all activated axes. This allows the servo enable to be
transferred outside the PLC cycle, for example.
The following signals are relevant:
Signal Type Type Value range Remark
Enable I BOOL 1= FC 21 active
Funct I BYTE 6 6: Control signals to axes
S7Var I ANY S7 data storage area Not used
IVAR1 I INT 0
Error A BOOL
ErrCode A INT 1: "Funct" invalid