VFD's and 3phase Induction motors FAQ corner / pls. Read all first

they are the same @hooshang ...
But I had to use two wire so to split them [V1 + CM] coming directly from the opt-coupler board output connector for motor 1 ... and [Directions "p1d1 & p1d2" + CM] coming from the limit switches which are connected in series and they are located in the actuator ...

@speedy
hello freind
two questions:
1-doeas the Simaxe ac coupler board works also with 12 v power supply or its better or have to use 15?
2-does this board couse some delay?
thank you
regards
Hooshang

Hi @hooshang ...
Good questions .

1- what ever you can use up to 30V ... But be careful that the analog output voltage going to VFD will be related to this input supply voltage .. Ex. [ 12vin > (0-12) V1out] & [15vin >(0-15) V1out] & ...etc.
2- Nothing is ideal ... and overall time shift/delay is there in the scale of the Nano & Micro second ... which is very very very acceptable .

In nearly all the platforms a control board is used with the VFDs. Why not connect the VFD directly to the PC (which is running the game) through RS-485 converters (Most VFDs support RS-485 modbus communication)?

I am looking for a VFD with the following specs:
single phase 220v, 50 Hz
2hp & 4hp models
Encoder extension board
Encoder pulse output (some VFDs like Delta VFD-B only provide speed calculated via encoder pulse)
CW and CCW motion prohibition input ( to use with limit switches)
communication module (RS-232 or RS-485, modbus ASCII is preferable)
would appreciate suggestions on brand and model.
thanks in advance.

You can connect a VFD directly to a PC thru rs-485 but not directly to simtools so you would still need another PC program as a go-between for communication unless your VFD has position control that is compatible with simtools output and you know how to set it up correctly.
Furthermore, unless your motion rigs design allows your rig to remain mostly balanced in all positions, you would probably need to implement a PID controller. While this may be possible with a PC program too, PID controllers use precise timing and are usually implemented on a microcontroller where the timing is not affected by other programs running in a multi-tasking environment like on a PC. Again though, if your VFD has a PID controller too, then it may be possible directly from simtools.

I know what you mean @aliotic ...

Please note first that VFD's are not all the same in commands and addresses when communicating with PC via RS485 ... I'm not a programmer , but I can tell you that until now, there is no universal driver or plugin solution for all VFD models that SimTools can use ...​

Simtools can't communicate with them all in a standard way ...

Unless the Famous VFD companies reveal their S/W source code to SimTools development @yobuddy ... to interface their devices through a drop down selection box ... Then we've beaten the SCN5 and SCN6 actuators as plug and play expensive equipment ...​

What is the need for the Extension board and the mod-bus module ?

What you can find here is that we are using the cheapest VFD category for the cheap and powerful 3 phase induction motor to do the job ...
Using a classic closed loop motion control system and using the VFDs as a 3 phase H-Bridge ...
So you can enjoy the Fact that you can use a simple Arduino with a feed back sensor and a small interfacing board connected to the VFD analog terminals ... and there you go .​

If you still need to use the RS485 then you might like the SCN5 ... Please read this first for How SCN5 connected with USB ... and Good Luck
SCN5 Wiring Tutorial

@Bluestoneracing
I appreciate your contribution to the VFD thread.
If you are still wiling to share your knowledge and experience then I will appreciate learning with you.
I have done some testing myself on drives:
Challenge 1) Positional Control. Drives can be controlled from the keypad, terminals or with communication. If you select communication then you will have to change direction through communication. How do you "break" or "set low" the internal "FWD" or "REV" command when the position is reached? On some drives reference can be set through communication and controlled at terminal level. Still though, If PID is selected then the drives only move faster and slower based on the error it calculated. How will one stop the drive and get it to go into a negative direction?

Challenge 2) Inertia. I have not tested this, but I am concerned about it. Not even sure if i should be. If you do get the "FWD" and "REV" commands to work then you will have inductive kickback from the motors every time you change direction. Caps will protect, but I doubt ones drive will change direction until a complete stop was reached. Possibly decreasing your sims reaction time. One will need a braking resistors then.

Challenge 3) Asynchronous RS485. Communication speed will have to be considered and tested running on multiple drives. Modbus read is out of the question. If modbus is used then writing to the drive should be the only function worth considering. If possible ( i believe on some drives this is possible) then communication feedback or rather modbus response from the drive should be disabled.

Could I kindly ask you to send me a link of a VFD that you will consider capable of being controlled through modbus, if you have one.

Also note. I do not expect solutions from you by sharing this. I am only interested at learning with you. I will likely keep my knowledge and experience for another rainy day. Even if I only learn the limitations of drives then this time and energy spend will be worth it. You will hopefully also benefit and be able to decide how to best go about using a VFD for your sim.

Just for my future reference for CB and wire sizes.

Hi,
Hi,
I am using Delta VFD-B drives. Each inverter has the appropriate break resistors. Communication is set to Modbsu ASCII with 38400 b/s baud rate. The control loop frequency is around 7 Hz. I have added encoders to the back end of the motor plus encoder extension cards on the drive. my problem is that these drives do not provide position feedback although there is an encoder present speed is calculated via encoder pulses and presented to the user as pulse/sec. in order to achieve position control i integrate the speed value read from the drive (after homing) which has a near satisfactory result.
The other problem with these drives is that they do not accept CW / CCW motion prohibition like servos. this functionality is important to stop the motor automatically when reaching the limits of the telescopic linear actuators. the drives have a stop input but what we need is the ability to stop the motor in one direction whilst allowing it to accept the other direction. for instance when the actuator reaches the top limit switch it should stop the motor but still be able to move in the downward direction.
I found the Delta C2000 VFD which is a little bit more expensive but has very good functionality however the problem is that the drive is a three phase inverter which is not suitable for me.
at the moment I am trying to implement @speedy 's advice and have bought arduino boards. An Arduino Nano board to read the encoders (used as counters) and one Arduino Mega 2560 to implement the controller and generate pulse direction signals for the drive. I have not completed so I can't provide further info.

Hi @aliotic ...
Good job so far ...
And to keep it simple so others can benefit from the concept ... As you can see normal affordable VFD's used here are NOT for tracking speed or position ...
I use/consider them just as a 3-phase H-Bridge for AC motors ...
The controller is a totally separate board + the opto-coupler VFD interfacing board .

FYI: We have a very good powerful code projects for Arduino's ... as I may suggest SMC3 is a simple and Big project with one Arduino Uno board to fully position control 3 motors at the same time with a normal 10k pot as position feed back signal ... read post 1 and post 2 for more information ...

And that is really Good Sophisticated Expensive piece of equipment ...


Thanks

A test video for the opto-coupler board as interfacing between Arduino and the VFD's ...



and here is with the SimTools running LFS game

The making process ...

@speedy
thank you mate for sharing all information about vfd very neat job,its been a great help atleast for me
well as you know ive done also about this with smc3,arduino and your optocupler before but iam goin to say
when I just tested this configuration it had a little delay to start motors ,do you have the same resaut or it was
my fault friend?
finally I changed resistors and got better resault
regards
Hooshang

@hooshang ... Thanks buddy .... and No delay with me at all ... !!!
So that's what you've been asking about before ...

- Do you encounter delay at all the time OR just once at the startup ?
- Which resistors you have changed ?
Explain more please ...

Regards ...

@speedy thank you for quick reply
- lets explain in this way ,the sensitivity of pot was very low all the time and even in output testing when i drag the axis to the
left or right it took much to make motors move.system was somehow lazy
- i got some information from @prilad (dont remember the link of thread) about optocuplers ,just using resistor 450 instead 2k2 and 180 instead 1k5
and got much better resault with much more sensitivity
regards and shokran freind
Hooshang

@hooshang ... Anytime buddy .
First make sure that Arduino output signals are in the 5v form NOT 3.3v ...
then you will realize that the 2k2 & 1k5 resistors are load resistors they only affect the operating voltage of the internal LED and transistor of the opto-coupler ...


If you still have problem ,So you need to increase the PWM input signal ratio .
I would recommend you to increase the PWMmax in the SMC3 up to 255 ...
As I previously used the SimCtrl FW of @prilad and increased the PWM to give enough signal to operate the motors ...

See if that solves the problem if there any .
Best Regards And shokran To you too ... = thank you in Arabic

@speedy
well thank you again " super Speedy"
iam not electrician,i've learned a lot from you and others here but let say ive done alot with SMC3 utilities and Ard
i have tested a lot of options on breadboard for this too and i want you to check what i said about resistors
and find an explanation for that or even test to find if iam right or not,
thank you

@speedy
here is your optocopler that i've modified

Hi @hooshang ...
Here is what I remember I did regarding the calculation of the resistors ...
Starting with the datasheet of the 4N35 optocoupler ...
http://www.ben.cz/_d/datasheet/4n37.pdf
on its second page it states the required forward Voltage and Current for the INFRA RED Diode ...


you can put these values with this online LED resistor calculator ...
http://led.linear1.org/1led.wiz



It will give you a 390 Ohm for the input resistor ... !!!
That would be the minimum standard resistor to be used with this optocoupler and you start to complete your total design calculation from that value .

So using a 180 Ohm for input resistor is IMHO is putting an overvoltage on the IR LEDs ... plus consuming more power from the Arduino for each 3 lines per motor output ...
On the other hand the 450 Ohm for the transistor side is not high enough to compensate the digital low state for the 74HC14 schmitt IC when the transistor is ON ... And the overall mA drown from the 7805 regulator will be huge [ heating problem ] ...
use this circuit simulator applet to see what I mean ...
http://www.falstad.com/circuit/

Anyhow ,I'm pleased that you're satisfied with the results you've found so far ... if you post some videos for it with the SMC3 Util. and the difference would be great .

Very nice drawing BTW ... I assume there is a jumper wire here

Can you just post the Doable pdf files for this through hole layout so others can benefit from it ...

Thanks and have a nice time .