Siemens SINUMERIK 828D Training Manual page 213

Data Exchange Between NC and PLC.
The 828D controller has a 512 byte memory area for use with data exchange
between the NC and PLC.
The memory available is from DB4900.DBB0 to DB4900.DBB511, allowing
data to be exchanged directly between the user PLC and for example a part
program.
It is possible to use Byte, Word, Double Word and floating point numbers to
be used as shown below:
$A_DBB[n] Byte format
$A_DBW[n] Word format
$A_DBD[n] Double Word format
$A_DBR[n] Real number
[n] should be substituted for the byte number.
To test the function, the value stored in R10 will be written into $A_DBB[4]
(The 4th byte of DB4900, i.e. DB4900.DBB4
The following program code has to be typed into the MDA area of the
Controller: $A_DBR[4]=R10
When the cycle start button is pressed the value be copied from
R10 to the destination variable.
This can be checked in the Chart Status of the PLC828 programming tool:
To read data the other way is a similar operation. In the MDA area type the
line: R11=$A_DBR[4]
This will copy the contents of $A_DBR[4] into R11
SINUMERIK 828D Page 15
Section 5
Notes
B033
B033