How to control speed of a 24V fan ?

[eagl1]

No PWM especially on the relay model,

But what do DA0 & DA1 do ? Aren't these pin the ones which provide PWM signal ? Or what do they do exactly ?

some transistor outputs will allow a sort of PWM

Yes, I know that on a transistor I can do PWM or similar pulse based on how fast the MOSFET can switch ON/OFF. But it's not practical to do it on a mechanical relays or SSRs.

but I doubt the clone will be able to use that instruction only the real FX3 is capable I suspect

ok, actually I didn't know that there are real FX3 controller boards. I thought this board is a simulation of the known high performance PLCs; like, siemens PLCs.

I learned that siemens uses high performance chips; like, SoC or ASICs and not microcontrollers.

there are a number of differences between the real Fx range & these clones. A friend of mine has one I will ask him to try it on the transistor output model to see if it works, so it may be possible to use PWM function with transistor outputs but not on the relay one.

No, it's OK, I know on the relay output it's not practical but on the other pins that are coming directly from the MCU, it's possible.

 

[eagl1]

So am I but from the posts it looks like the OP is using a relay output plc so the PWM instruction does not work.

Yes, I chose the relay model because I want to control AC 220V loads.

But as an example I included a 24V DC fan. Even I had a little idea that this board provides some output pins that aren't connected with the relays, so those pins could be used as digital outputs.

I would've gone with the transistor outputs and where required, drive external relays via transistor.


Craig

That's a good idea too.

 

[parky]

DA0 & DA1 are analogue outputs i.e. 0-20ma or 0-10v there is no PWM output the FX uses some of the outputs as PWM but it has to be transistor type if you have a transistor output unit you could use relays to drive the higher voltages.

 

[Tinine]

DA0 & DA1 are analogue outputs i.e. 0-20ma or 0-10v there is no PWM output the FX uses some of the outputs as PWM but it has to be transistor type if you have a transistor output unit you could use relays to drive the higher voltages.

Hence post #6

Craig

 

[parky]

back to your post #16 these are rip offs of the Mitsubishi FX range probably made in somebodies shed in South east Asia, These are not genuine articles & probably not approved by any authority. There are limitations for example on a genuine FX3U the PLC parameters like retentive areas can be adjusted, most of these clones do not allow modification of the PLC parameters so are limited to the default what ever those are, Expansion I/O or add on inteligent cards probably cannot be connected, certain functions do not work (brings me back to a possibility of the so called FX3U is a mash up of the early FX firmware).
All the genuine FX0-3U are 422 programming port most of these clones seem to have only 232, the baud rate on the genuine FX3 defaults to 9600 & the programming environment can force it to any other upto 115kb, the clones I have seen only work at 19200 & cannot be forced. You get what you pay for & there seems to be a trend of cheap electronics from Asia failing after about a year, a friend of mine buys loads of the cheap electronics & most stop working within 9-12 months I am begining to suspect that a lot of these items are designed to self destruct after a certain time, It is interesting that he purchased about 8 mini cameras (ones with DVR recording) of different makes, he was always into these gadgets i.e. in car recording, underwater filming etc. all but one has failed within 12 months, it also seems to be a common fault i.e. seems to be working but does not record anything. seems very fishy to me.

 

[lfe]

There is a lot of uncertainty in what you want to do.

That small fan may stop if the voltage is lowered, since usually they do not work like a normal DC motor but with a small oscillator that simply stops working if the voltage is not enough.

You should test the fan with a variable power supply and see what happens when you lower the voltage.

Also, on this FX clone many of the special instructions of the original FX don't work, like the one that generates PWM pulses with transistor outputs.

 

[eagl1]

Hence post #6

Craig

Thank you so much, I didn't notice that post

Now it's getting more interesting. So there's this board that converts the variable DC voltage to a PWM signal.

I'm now more interested to know if it's possible to also communicate with a microcontroller for more control tasks.

 

[Tinine]

If you really wanna have some fun, grab one of these

Analog inputs (you'd need to level-shift, mind) lots of PWM outputs, 2 X 12bit DACs, etc. Something like 47 I/O

If you go with the display, it has a 16bit parallel interface and is quite snappy.

You can be up and running in minutes. All you need is the .bin firmware in the attached zip-file. It's a child's-play interpreted BASIC that runs at close to ~100,000 lines/sec.

Craig


Manual on my Dropbox

 

[eagl1]

If you really wanna have some fun, grab one of these

Analog inputs (you'd need to level-shift, mind) lots of PWM outputs, 2 X 12bit DACs, etc. Something like 47 I/O

If you go with the display, it has a 16bit parallel interface and is quite snappy.

Oh yeah I actually work extensively with microcontrollers.

I'm electronics trainer and I'm training graduation projects course for diploma program now for like 2 years, I do most of the projects with arduino, esp and stm32 boards.

But this semester I wanted to do some projects with PLCs.

I learned that PLCs are for industrial and commercial applications, and 24V is the standard digital input/output voltage level.

Everything else need extra voltage work.

I actually visited a cement factory the last year and the engineer showed us the control box of the whole factory. It was two big size siemens PLCs, one is running and the second one for backup operation.

The next box was input/output card, the next box was the signal conditioning which was a new topic for me.

I didn't get it completely at that time, but now I have more idea of what signal conditioning is, I think it's leveling everything voltage signals coming from all the different sensors which aren't necessary work at 24V, to level and condition them to be in the scope of 24V. Am I right here ?


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So PLCs work mostly with reading and writing analog/digital signals.
But doesn't work with PWM or any other serial signals.

But what about other modules that work with serial communication ?

You can be up and running in minutes. All you need is the .bin firmware in the attached zip-file. It's a child's-play interpreted BASIC that runs at close to ~100,000 lines/sec.

Craig

You mean the .bin file is for the STM32 board ?


Edit:
OK, I got the files, there's a manual for the board

Thanks man for the help.

 

[eagl1]

There is a lot of uncertainty in what you want to do.

That small fan may stop if the voltage is lowered, since usually they do not work like a normal DC motor but with a small oscillator that simply stops working if the voltage is not enough.


You should test the fan with a variable power supply and see what happens when you lower the voltage.

OK, I will do the testing, the setup is for a training project for students.

The project is done for educational purposes.

Also, on this FX clone many of the special instructions of the original FX don't work, like the one that generates PWM pulses with transistor outputs.

Why it won't work ? does the original use stm32 chip or it's a completely different controller ?

Also how to know all the instructions ? is there a source ?

 

[parky]

Many PLC's do PWM & the FX3U does but only on the transistor output type, relays are not fast enough.
Not sure if the clones can use that instruction some are limited so it may not work. On some of the clones it is the in-built software that interprets the mitsubishi code that does not have all functionallity If you want to use a PLC then either use a DC controller board that works off 0-10v input or use the ladder network shown before.
Here is a possibility a 0-10v to PWM converter you then need a PWM DC motor control board
https://www.amazon.co.uk/Voltage-Co...-8-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9tdGY&psc=1

Or perhaps get one of the many DC controller boards with a potentiometer & build an interface 0-10v to connect in place of the normal potentiometer.

 

[geniusintraining]

Its been years but I did something like this...

I use this https://www.amazon.com/Controller-Regulator-Potentiometer-Overload-Protector/dp/B07D281HXS

Replaced the potentiometer (it was 12vdc) with the output from the PLC and worked OK, I was looking for a new trainer to build but I never finished it

 

[eagl1]

back to your post #16 these are rip offs of the Mitsubishi FX range probably made in somebodies shed in South east Asia, These are not genuine articles & probably not approved by any authority.

Yep the clones aren't like the originals absolutely, and mostly doesn't use the same programming setups or the controller chip. It could be a mimic to the original with a approximate PCB design and functionality.

Unless the original is an open source technology, then anyone can copy the core programming setup and the hardware specs, and do an exact copy or build a clone with different parameters or features.

But I haven't done any work with PLCs, and all I know is that siemens is a pioneer in this field, then I learned that there are other big companies that also do PLCs.

So I don't know much about Mitsubishi PLCs or even its programming environment.

I ran into a page about cybersecurity company, and the page talks about reverse engineering a siemens PLC and how they faced a hard time trying to hack that thing, so it was a very hard task to do and all they could do is getting some code and the chip info with a microscope.

There are limitations for example on a genuine FX3U the PLC parameters like retentive areas can be adjusted, most of these clones do not allow modification of the PLC parameters so are limited to the default what ever those are, Expansion I/O or add on inteligent cards probably cannot be connected, certain functions do not work (brings me back to a possibility of the so called FX3U is a mash up of the early FX firmware).

Thanks for the info, I should learn more with time working with this clone. The students have purchased it, but it didn't arrive yet.

All the genuine FX0-3U are 422 programming port most of these clones seem to have only 232, the baud rate on the genuine FX3 defaults to 9600 & the programming environment can force it to any other upto 115kb, the clones I have seen only work at 19200 & cannot be forced.

Does this mean, that it's not possible to program the clone in the official Mitsubishi programming IDE ? so the IDE won't recognize the clone.

You get what you pay for & there seems to be a trend of cheap electronics from Asia failing after about a year, a friend of mine buys loads of the cheap electronics & most stop working within 9-12 months I am beginning to suspect that a lot of these items are designed to self destruct after a certain time, It is interesting that he purchased about 8 mini cameras (ones with DVR recording) of different makes, he was always into these gadgets i.e. in car recording, underwater filming etc. all but one has failed within 12 months, it also seems to be a common fault i.e. seems to be working but does not record anything. seems very fishy to me.

Actually I have no experience with these clones, I've purchased some arduino clones, some stm32 boards and other controller boards from aliexpress.

Also even with arduino clones they are different, some clones use a microcontroller for the communication with the usb and some use a usb/uart converters. Some work and some don't work, but most clones work ok.

 

[lfe]

Why it won't work ? does the original use stm32 chip or it's a completely different controller ?

Also how to know all the instructions ? is there a source ?

Mitsubishi FX has high-speed instructions that execute independently of the scan, such as direct encoder inputs, PWM output and others.

I don't think that clone have something like that.

I have no idea what processor Mitsubishi and other brands use, I don't care.

You can download the Mitsubishi programming manual on the internet

 

[eagl1]

Mitsubishi FX has high-speed instructions that execute independently of the scan, such as direct encoder inputs, PWM output and others.

I don't think that clone have something like that.

I think you mean interrupt driven input/output pins.

Microcontrollers have interrupt driven pins that can scan or output things independently but when the interrupt occurs, the CPU must stop of what it was doing and handle the interrupt request, then get back and proceed its previous task.

The clone has STM32 chip, and one may program its to do so.

What I understood is that the clone is a STM32 microcontroller which basically programmed in C language. But who designed this PLC clone, arranged it to be programmed in PLC environment.

I found a page of a programmer who tried to reverse engineer the clone PLC and program it with Arduino:

https://www.hackster.io/galopago/repurposing-a-plc-clone-for-use-with-arduino-2fb5e0

I have no idea what processor Mitsubishi and other brands use, I don't care.

You can download the Mitsubishi programming manual on the internet

I checked some Mitsubishi manuals, wow, it's my first time getting into this world of manuals, all my experience is with microcontrollers datasheets and programming ebooks. PLC world is different and interesting.

But I tried to know what chip they use but the manual has technical details but I couldn't find this information.