Import of a technical question from the user Okod

Okod

Hello,

I am working on a project and need to measure the speed of the motor and I think I have to start with using the PWM function:

1/ I've tried to use the PWM function many time but it did not work with me, so how can I configure it?

2/ I've tried to use the HSC to measure the RPM for the motor but it also does not work with me, so I need to know how to use it.

3/ In some chats I observed that if I want to read the motor speed I could not unless I have an incremental encoder, is this right? and if it is right what type of encoders that can be appropriate and how to connect it with the PLC.

Also I've tried the MC_Power and MC_MoveVelocity and when trying to apply the commissioning I've got this error.

A communication error occurred in the control panel (Timeout)

I.e I just couldn't transfer from automatic to manual control at the commissioning box.

Can anyone advice please.

Okod

Can anyone advice please.

 Doubtful. Your questions and description of the problem is very vague.

But in general sense, if you want to measure the speed of a motor you will need as you stated some sort of feed back like and encoder and then you connect the encoder to the inputs of your PLC which I'm assuming is a S7-1200 of some sort considering you posted here. And with the aid of HSC and some fancy logic and math you will be able to calculate the RPM of your motor.

Best to specify the following:

Type of motor and drive.

Type of PLC and version number.

The version of your programming software.

Thank you very much Kal.A for your interests and answer, and yes I am using S7-1200 1214DC DC DC with software V13.

the motor drive along with the board are educational kits by Siemens and I have tried to attach a photo of them but I couldn't.

Sorry I'm not familiar with the kit you mentioned. Are there name plates on the motor and drive? there's gotta be something.

And what are you trying to do? You mentioned you're configuring a technology object of some sort.

You're missing out on a lot of help from the experts on this forum by not sharing more detail.

Thank you again and sorry for being vague as you mentioned but it was not intentionally indeed.

I am trying to apply Fuzzy logic and PID controller on controlling the speed a DC motor on TIA software for academic purpose. So at an earlier level I need to be apple to read the motor velocity through PWM output when the motor is on action.

Please see the attached pdf file for the kits.

Okod

I am trying to apply Fuzzy logic and PID controller on controlling the speed a DC motor on TIA software for academic purpose.

 Oh dear, another academic fuzzy logic project that should not be using fuzzy logic.

First, let's solve your problem.  To get speed, you need a time base.  That means you need to process your counter signal in a time based interrupt.  Speed = change in counts/ time base.

Second, you will find that fuzzy absolutely sucks for trying to implement speed control.  Every year, people do this and every year, people give up because it simply is not a good application for it.

If you want to make a rice cooker, use fuzzy.  If you want to do something serious, forget it.  If it was useful, the industry would have adopted it 20 years ago.

Thank you guys for your information and yes I recently knew that fuzzy logic on PLC for DC motor is not a worthy project, but unfortunately I have to try it.

For the point of using counter as a time based, which type is it HSC or the normal counter?.

 On other side, in the board I have two points I0.4 & I0.5 (LEDs) that making signals when the motor cut their fields, i.e. when the motor cut any one of them  4 times that makes 1 rotation. So can I use the counter to count the speed using these to inputs I0.4 & I0.5 ? If it is possible please advice.

The two LEDs are visible in the attached pic next to the rotor one of them is on and the other of.