Today is...
Tuesday, February 20, 2018
Welcome to, the global online
community of automation professionals.
Featured Video...
Featured Video
EtherCAT with CTC’s master lets your multivendor network play well together...
Our Advertisers
Help keep our servers running...
Patronize our advertisers!
Visit our Post Archive
Simulated Integer Values
I would like suggestions on how to "fluctuate" integer values randomly within a certain range in a Siemens S7/TIA Portal project and display these values on an HMI.

I am working on a simulated TIA Portal project which entails generating integer values and would like it to display on the HMI screen. The way I chose to generate these values is to initialize them as an integer value on a data block. To make it look more realistic to the process, I would like these values to fluctuate close to the initialized value in the data block. I would like to "fluctuate" these values a few units or a percentage and show this fluctuation on an HMI screen. I would like some suggestions as to how to do this in a looping manner.

Writing simulation software for testing control software is an art in itself - but not too difficult!

You want to vary some integer values? Ramp up from say zero to hundred, pause then ramp down to zero - but at what speed? Or start from an initialized value and jump to several preset values in sequence.

The only limitation are your specific requirements and imagination - coding is the easy part.

Thank you for your reply.

Yes, I would like to vary integer values. I am not as concerned about the ramp up/down from a start or shutdown as I am having it vary at a predetermined value while in the run mode so the reading would not be static. An example would be a 3600 rpm motor varying within a few rpm in either direction randomly.

Still trying to figure out the best way to do this-adding noise to an integer in a data block. Any help is very much appreciated.

Look at something like this:

Should be easy to implement a 2^16 version if using 16 bits registers.

Not good for cryptography.