Program Management - Toshiba V Series User Manual

3.4.3

Program management

The programs, user functions, and user function blocks are managed in a unit called
POU (Program Organization Unit) by the program proper consisting of instruction
words. Each program, user function, or user function block uses one POU.
The program proper is arrayed in the code memory, which has a structure divided
into memory blocks (each consisting of 512 bytes). One POU exclusively covers
two or more consecutive memory blocks according to program size.
The tables below show the number of POUs and of memory blocks of the L1.
In registering a program, exercise care not to exceed the program capacity.
example, if a program such as shown below is created, followed by batch
downloading, 41 blocks of the code memory will be occupied.
In downloading a program online, the controller searches for consecutive blank
blocks in which the program can be stored, and downloads it there. If there are no
blank blocks wherein the program can be stored, however, the program cannot be
downloaded online. In such a case, stop the operation, and download the program
by batch downloading.
6F8C1005
Table 3-2 Program Management
Model No. of POUs Code memory size
L1 64
Program
Main scan task: 8
Program 1
Program 2
Program 3
Program 4
Program 5
Program 6
Program 7
Program 8
User FB (Used in program 1)
Total
No. of blocks: No. of steps/128.
will be rounded to a unit.
Code Memory Management Table
0 1
0 MS_0 P_0
1 P_2
2
3 P_5
4 P_6 MS_7
5 P_7
Figure 3-2 Example of Program Capacity
No. of steps
24 K bytes 6 K steps
No. of
steps
MS_0 to MS_7
P_0
P_1
P_2
P_3
P_4
P_5
P_6
P_7
P_8
If not divisible exactly, the remaining fractions
2 3 4 5
P_8 MS_1 P_1
MS_3 P_3
P_4 MS_5
MS_6 P_6
P_7
3.4 Program Management
No. of memory
blocks
48
For
No. of
blocks
8
－
100 1
200 2
300 3
400 4
500 4
600 5
700 6
800 7
100 1
3700 41
6 7
MS_2 P_2
MS_4
P_5
(1block)
89
3