Siemens SINUMERIK 840Di Function Manual page 42

Detailed Description
2.2 Functions
Block
number
N10
N12
N20
N30
N40
N50
N60
N70
N80
N90
N99
Activation
The maximum number of output variables that can be written to simultaneously can be set
with:
MD28150 $MC_MM_NUM_VDIVAR_ELEMENTS
Example
A WORD is to be transferred from the PLC to the NC.
The position offset within the NCK input (PLC output area) should be the fourth byte. The
position offset must be a whole-number multiple of the data width.
• Writing from PLC:
Program code (extract)
. . .
CALL FC21 (
Enable :=M10.0,
Funct :=B#16#4,
S7Var :=P#M 104.0 WORD1,
IVAR1 :=04,
IVAR2 :=-1,
Error :=M10.1,
ErrCode :=MW12);
. . .
)
2-30
Example
Addressing the problem by means of comparison on f "EPSILON" (minor deviation)
Program code
DEF REAL DBR
DEF REAL EPSILON = 0.00001
$A_DBR[0]=145.145
G4 F2
STOPRE
DBR=$A_DBR[0]
IF ( ABS(DBR/145.145-1.0) < EPSILON ) GOTOF ENDE
MSG ( "error" )
M0
END:
M30
Comment
;if TRUE, then FC21 active
Various NC/PLC Interface Signals and Functions (A2)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0