6.6 OB 126: Define, Transfer Process Images
Each time the cycle is run through, the system program updates the
process image of the digital inputs and outputs and IPC flags. The
inputs, outputs and IPC flags included in the process image are stored
in system data block DB 1 (refer to Chapter 10).
With OB 126, you can use additional process images.
Function
Using OB 126, you can program up to four further process images in
addition to the process image in DB 1 during a COLD RESTART.
These additional process images can be read in and output with the
STEP 5 program at any program execution level.
Parameters
1. Data field
6 flags with the following structure:
Bit no. 7 0
FY n Function no.
FY n+1 Address list no.
FY n+2 Block type
FY n+3 Block number
FY n+4 Data word no. of the first ID word
FY n+5 in the address list
Parameters of the data field:
Function no.
With the function number, you stipulate which job OB 126 is to
perform (refer to the table).
Permitted values: 1 to 5
Function no. Function
1
2
3
4
Read in the process image of the digital inputs
Output the process image of the digital outputs
Read in the process image of the IPC input flags
Output the process image of the IPC output flags
5 Set up system internal address list (analogous to
DB 1)
(only permitted in COLD RESTART OB 20)
OB 126: Define, Transfer Process Images
CPU 948 Programming Guide
6 - 20 C79000-G8576-C848-04
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