PID Control in RsLogix 500 for Allen Bradley Micrologix and SLC 

¡De nada!

You are welcome Augusto.

You are welcome.

Thanks!

Thank you!

We have some coming.

No and we've brushed on this in several videos but I don't know that we have ever addressed it directly. While analog is "infinite", the it comes into the PLC as digitally with a certain bit resolution. In the case of the Micrologix, it is 12 bit resolution which means that it chops the full scale into 4096 increments. Now someone will probably come along and correct me and say that the Micrologix is "15 bit" resolution since its scale 0-32760. However, the Micrologix shifts the data by 3 bits, ignoring bits 0, 1, and 2 and placing the data in bits 3-14. I should do a video on this...oh wait, as I type this I remember I wrote an article about this. See link below. www.theautomationstore.com/rslogix-500-analog-bit-resolution-and-precision/

Tim Wilborne great read, thank you for the reply!

No, that might make an interesting video.

Glad you think so!

We are going to lightly touch on that in an upcoming video.

Check out this video series. twcontrols.com/safety-plc-lessons

Not enough info, many different ways depending on the hardware.

Here are all the PID videos I have done so far twcontrols.com/pid-control-proportional-integral-derivative

Yes there is, I'm getting ready to pick back up on PID videos and will cover it.

Sounds like your set point is outside of the minimum and maximum range.

Maybe, we don't typically get into SCADAs on this channel but we do have a small HMI/SCADA series coming that we might cover that in.

@@TimWilborne thanks tim.please I am waiting for it

Shooting from the hip since I didn't watch it before replying but wasn't F8:1 the level set point? This is the desired level for the PID and we manually enter it. The 2nd SCP scales the value which we entered via the data table to PID units.

Thanks Tim for your great work, do you please mind clarifying the use of the F8:1 float and it is unused and it's still puzzles me where it's getting its input from. I would have expected you to use F8:0 rather. Thanks

You would find the high and low setpoint on the documentation.

See link below. twcontrols.com/plc-lab

It is from PLC Cables, here is the link controls.tw/pidtrainer

Not without a lot of work, you will need some hardware.

@@TimWilborne Thank you Sir. So I have weighed my options and presently I believe i can manage the " a lot of work". That is considering the hardware alternatives. I have been doing bits and pieces on SIEMENS TIA portal(works great). I believe with some research and lots of your help, it may just work . Thanks again.

PID scale is 0-10,000. The raw formats of those three numbers are the same but it is good to check because not all of them are the same across the Micrologix line. Check out this link. www.theautomationstore.com/rslogix-500-analog-bit-resolution-and-precision/

@@TimWilborne thanks

The most common problem is not having any values in your parameters

Thanks Tim, CV% don't move, the imput, pv is in play also not out from block pid

But what are your variables set to?

He's pretty sharp at both :)