CONFIGURATION
FUNCTION BLOCKS
4 - 2
I-E96-211A
®
Function Code 19 PID:
36 Bytes NVM
116 Bytes RAM
690 microseconds execution rate
Function Code 82 Segment Control:
60 Bytes NVM
256 Bytes RAM
NOTE: In this example, execution time for this function is negligible.
2. Specify the number of blocks for both types. In this exam-
ple, 205 square root blocks, 205 PID blocks, and 2 segment
control blocks are configured.
3. Assign priorities to segments of these function blocks. Give
the segment of blocks controlling the most critical functions
the highest priority. The execution rates are listed in Table
4. Calculate the amount of NVM the configuration uses:
a. Multiply 205 PID blocks by 36 bytes per block = 7,380
bytes of NVM.
b. Multiply 205 Square Root blocks by 12 bytes per block
= 2,460 bytes of NVM.
c.
Multiply 2 Segment Control blocks by 60 bytes per
block = 120 bytes of NVM.
d. Add products:
7,380
2,460
+
120
9,960 bytes of NVM
There are 79,042 bytes available at the beginning. There
are 69,082 bytes of NVM remaining.
Table 4-1. Function Block Execution Rates
Control Type
Rate of
Execution
PID
Block
Square Root
Block
Critical Control
20 times/second
5
5
Normal Priority Control Loops
4 times/second
100
100
Low Priority Control Loops
1 time/2 seconds
100
100
