trying to make a mini control panel for a industrial motor using arduino, so far I already done the human interface but having trouble with the motor interface.
Iam gona drive a motor inverter that accepts a analog 0-10V range. I understand that arduino analog outputs arent true analog but rather PWM signals, I have searched the web and found documentation leading me to RF low-pass filters and op-amps. But to be truth this is stuff that I am not comfortable with, I can make the circuits but I have no idea what a RF low pass filter is and what op-amp to chose and how to properly set-up it.
I must say I am not really good in electronics I am all self thought, my background is mostly programing
helderferreira:
trying to make a mini control panel for a industrial motor using arduino, so far I already done the human interface but having trouble with the motor interface.
Iam gona drive a motor inverter that accepts a analog 0-10V range. I understand that arduino analog outputs arent true analog but rather PWM signals, I have searched the web and found documentation leading me to RF low-pass filters and op-amps. But to be truth this is stuff that I am not comfortable with, I can make the circuits but I have no idea what a RF low pass filter is and what op-amp to chose and how to properly set-up it.
I must say I am not really good in electronics I am all self thought, my background is mostly programing
if anyone can help me I would be grateful
Thanks in advance.
The RF in low pass filter just means it's designed to work at radio frequency, much higher in frequency then the arduino PWM output switching frequency used. Typically for arduino PWM use, one uses a simple R/C (resistor/capacitor) low pass filter. This converts the variable PWM duty cycle output to a smooth DC 0 to +5vdc true analog voltage. This is then typically wired to an op-amp buffer/amplifier to increase the variable output voltage range to your requirements, 0-10vdc in your case. It's a common circuit and I'm surprised you haven't come across on in your searches.
Perhaps some member here has a circuit they can post for you.
thanks for the ideas, I didnt knew about that DAC product, something to consider.
ok so the dac does a output of 0..5v am I correct, and I would need a op-amp IC to get 0..10v? Can I use any of these instead of the one you mention? Since I already have them ua741, tlc2272, mcp6482?
If the controlled device already has a 10v source, then possibly a digital pot or a mechanical pot setup might be possible. If the motor controller has accessible parts, you may be able to bypass its pot setup and use the arduino PWM to directly control the current control parts of the motor controller.
If the controlled device already has a 10v source, then possibly a digital pot or a mechanical pot setup might be possible. If the motor controller has accessible parts, you may be able to bypass its pot setup and use the arduino PWM to directly control the current control parts of the motor controller.
I think the OP wants to use the arduino to control the VFD . (Variable Frequency Drive) but I think it's a stretch to think he could hack it if he's asking the question he is asking. But you did inadvertly touch on a very viable solution. Almost all VFDs provide several means of control, one of which the OP mentioned being the analog 0-10V. But what the OP may not know , is that if he
looks at the manual for the VFD, there is a very strong possibility that it also provides a PWM input option, as that is found on almost all VFDs. I don't want to say that it is a standard, but I have seen it on all the VFDs I have worked on. (Baldor, Danfoss)
If he can find the manual or read the model number off the serial number plate we can pull the manual off the web and find out the input pin for the PWM.
It has to be with a VFD, no way arround it, because of security reasons I was told.
I have no idea if the VFD can be driven by PWM, the person Iam working for says that it has to be a pure analog signal from 0..10v, rest he told me is that the VDF its from SEW brand, afaik its a popular brand.
I asked a old friends help and we made a circuit using a ua741 opamp, I can now get it to 10v, probleam is that a PWM value from arduino lower than 4v the Opamp or circuit doesnt scale to that.
A value higher than 128 in arduino I can get a correspondent in the output of the opamp, lower its always 4v on the output.
I would buy the DAC product that was announced before but being in portugal makes it harder to aquire it.
It has to be with a VFD, no way around it, because of security reasons I was told.
If this is more than just a hobby project and real security is involved, then then DIY components probably actually add risk and issues that should be addressed. If the device is used in a commercial environment, it is probably best to buy the commercial equivalent .
It has to be with a VFD, no way around it, because of security reasons I was told.
I don't uderstand the term "security" in this context, It's clearly nothing to do with anti hacking or such, nor is it ( as I'm used to) anything to do with fault tolerance (it keeps going even when lots of the hardware has failed).
Maybe you such have a very good long chat with the boss a fing out what he really means - it's clear to me that you don't understand......
I understand programming, and the human interface is all done, a LCD and a keyboard to input data its all set.
For a simple console to imput RPM to a motor, arduino is enough and dont need to get a expensive PLC console for such trivial task, and its a inhouse project its not for resell, the industrial VFD is used because it has safe-backs built-in such as emergency button, obstruction detector etc.
What iam not familiar is outputing to the VFD in the analog form, I read it is possible but I couldnt find any schematic avaible for such task, I found stuff but its all bits and pieces.