How to apply the detailed method for CPU Load Calculation whether for AC450 (pm511 redudant) and SG415(Pm150 dual)
there is a function written in ac450 and ac410 user's guide states
CPU load=NF*T*100/(TS) %
as NF=Number of Functions
T=excution time for the function
TS=cycle time for the function in PC
i want to understand how to apply this to estimate CPU load that will be caused after adding new signals and functions to our system.
Voted best answer
NF = The number of functions, cannot be explained further
T=Execution time, can be found in PC Elements Reference manual
TS= the cycle time of the control module where the element is inserted
Use the values for a rough estimation.
You can also write the code in FCB, and use the PC-section\computing time function. The result gives you an indication. It usually give quite a accurate values for the PC-section.
Don't forget to also calculate load for I/O:s, TTD:s and communication.
In most applications, the main CPU load originates from more complex functions, such as PIDCONA, MOTCON, VALVECON and so on. Calculate those first, they are likely to cause the lion part of the CPU load.
But the first thing you have to ask your self. Do you have a CPU load problem!? There are few systems on the market, more stable than the Advant controllers. They can run with very high load.