How to detect sequence signal explicitly

hi all

let say i have vector signal V (1x5): V=[2 4 1 7 9]

how we can get in which position is our signal:

for example, by V, then 4 is signal number 2 or 9 is signal number 5. how we can get like that in simulink???

thanks

Answer 1

[Doug Eastman]

If you are using R2010a or later you can use the Relational Operator block in Logic and Bit Operations to compare the vector V and the signal S using the == operator, then send that output to the Find Nonzero Elements block in Math Operations.

[Luhur]

why find non zero element in math operation??? i just want to get the positio of the signal.

for example:

if value V is the signal, V=[2 4 1 7 9]

and S is the number of signal position, S=[1 2 3 4 5]

let say we after some condition value V that appear is 9, then also appear the number of signal position which is 5 because 9 at the end of signal S which is signal number 5.

get it???

[Doug Eastman]

From what I understand you want a system with two inputs and one output. One input is a vector (V), say [2 4 17 7 9], the other is a signal (S), say 7. You want the output to be the position of S in V, in this case 4. Is that right?

If so, that's exactly what I'm describing above. The relational operator will output a vector [0 0 0 1 0] where S==V, then the find block will output the index of that location, in this case 4. Make sense?

Answer 2

[Luhur]

i see.. but doug, after i tried it, the error in simulink was in find nonzero elements block...

the error was: The signal at output port 1 of 'detect_signal/Find Nonzero Elements' is a variable-size signal with a nondiscrete sample time. The sample time for any variable-size signal must be discrete.

[Doug Eastman]

Yes one of the limitations of this block is that it will need to be run with a discrete sample time. Is that acceptable? If so, you can enter the sample time in the block (i.e. enter 0.01 if you want the block to run 100 times a second).

[Luhur]

nice doug,another alternative. but i prefer the answer in this post http://www.mathworks.com/matlabcentral/answers/11500-detect-smallest-or-bigest-value-of-signal-in-stateflow-and-simulink

THANKS DOUG!!! NICE!!!