How to calculate arithmetic average of an analog input in the TIA V12

Staff

There is a way to create a FB to calculate a 
sample average of an analog input , because I have a 
lot of ocilação this input, and want to calculate the 
media to reduce this fluctuation values.
Making the calculation .
(X1 X2 + X3 + ... + Xn ) / n

Hello martens;

Depending on where your problem originates, there are different solutions:

- if you have an oscillating value is provoked by electrical noise at the analog input, you could check the noise rejection (filtering) parameters of your analog input module and see whether you can stabilize the input by increasing the filter value (in Hz).

- if you really do need to do a "running average" of the process values read by your analog input channel, maybe this FAQ could help:

In STEP 7 (TIA Portal) how do you calculate from an arbitrary number of read-in values a current arithmetic average value for the S7-1200/S7-1500?

https://support.industry.siemens.com/tf/ww/en/posts/86224/

Hope this helps,

Daniel Chartier

You may want to look at this

https://support.industry.siemens.com/cs/document/6170416/software-low-pass-filter-in-step-7-v5x?dti=0&lc=en-WW

It was developed for S7 v5.5, but, if you can open it, there is SCL source code that should be transportable.

I have attached the FB (in STL).  It should be very easy to replicate in SCL or even LAD.

My problem is not noise but variation in the very process.
I am measuring the diamentro a roll but this has vibration
and vibrates the sensor so that there is variation in the 
measured value due to mechanical vibration, so I want to 
calculate the average for vitar variations sudden in control

hi martins,

check if your analogue input module has a smoothing option. With this option you will get an average in the Input-Word and you don´t have to programm anything. You can find it in HW-Config.

Hope this helps, 

regards,