Siemens SINUMERIK 840Di Function Manual page 1142

Detailed description
2.12 Block descriptions
Call example
1. Read double word of position offset 4 with semaphore in byte 0 and store in MD 100:
Data type Dword (4 bytes)
Position offset 4
CALL FC 21 (
UN M10.1;
R F10.0;
Examples of NCK programming:
Data transfer from NC to PLC, with data written via synchronized actions;
Byte 0 serves as the semaphore
ID=1 WHENEVER $A_DBB[0] == 0 DO $A_DBR[4] = $AA_IM[X] $A_DBB[0] = 1
2-230
Enable :=
Funct :=
S7Var :=
IVAR1 :=
IVAR2 :=
Error :=
ErrCode :=
//Enable while 1, until value is read
M 10.0,
B#16#3,
P#M 100.0 DWORD 1,
4,
0,
M 10.1,
MW12);
Power Line Basic PLC Program (P3)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
// if True, FC 21
is active
//Read data