Hydraulic SYM

@Bernd Manger ... what are the transducers for ? He has a direct analog feedback ...

Which transducers do you mean:
The Micropulse transducers (actuator feedback) or the position transducers (part 5 in the hydraulic valves) ?

And what do you think where the "direct analog feedback" comes from ? Out of space ?

I'm sorry ... I don't understand the "out of space " tone .
Please elaborate more ...

Arrggghhh !! That was a Joooooooke ! Joke, joke, joke, joke !

I never thought that english is so difficult.
My english is just good enough to ask for the next bus stop, and not to make a little joke.

Since my SIM is almost finished anyway, I decided to become a passive member again.
I think that some members will be happy about it.

Sorry Marco, but I'm sure Speedy will help you:

Yeh @Bernd Manger thanks you're a good helpfull man and I hope you keep it that way ...

My point is you forgot you said earlier that those micropulse have a 0-10v feedback where a voltage divider can be used to make it compatible to the Arduino 5v input ... or that's what I've understanded it .
and you suggested in 2 pages earlier that not to bother with coding as it is already DONE for UNO using 3 motors and very well tested ...
https://www.xsimulator.net/community/threads/hydraulic-sym.9604/page-4#post-124365

No need for coding I believe ... all what you may need is equipments interfacing .

Yes I know that hydraulic systems go UP TO 3000psi.
Looking at his pressure gauge he has a system that runs at a more standard pressure of 1800psi.
Carbon dioxide Co2,refridgerant has a working pressure of 1800psi.

Marco,
I do believe both Bernd and Speedy are both partly correct.
The lack of info and pics on your part makes it harder for anyone to help you.

The confusion on how your actuator uses positional sensor to control the spool and coil.
Depending on how it was designed to operate, whether it uses..

Pwm coil and spool position to tell it when it has reached commanded flow position, I would compare this to a PID control of 2 separate systems.
PID of oil flow and direction from proportional valve and a second PID for the hydraulic cylinder position.
This is what Bernd kinda suggests as the working principal.

The proportional valve operates from averaged pwm signal giving a pseudo analog voltage which translates to defined spool position, this method is less likely to be used and only requires a single PID to control both valve and cylinder.
This what Speedy thinks is needed.

Am I missing something ?









You'll get rid of that unknown for SimTools Siemens controller ... and use one Arduino UNO programmed with the SMC3 code ... and for signal shaping to suit the valves you'll use any 0-10v DAC .

at least @Marco Dias you can give photos as expected otherwise it is going to be freezing here too .

Hi guys

Sorry for the the delayed reply...

Been working on a different project ( a robotic arm I had bought a few years ago)

Tomorrow I will take some pictures of the items I have. Which are faulty and explain what the problem I have to the best of my knowledge...

Many thanks for all your input...

Dear All

I am back on this project at long last...

SO... I have decided to scrap all the electronics that came with the sim and keep only the working mechanical parts.

Because The Atos valves replacement are simply far too expensive for me, I have decided to do a bit of research and testing out and been successful with my discoveries..

basically i started looking into what actually the electronics on the valves were doing and came to the conclusion that all it does is control the current on the coil making it go backwards and forwards faster or slower making the cylinder go one direction or the other faster or slower... so i decided to check the market for 3rd party proportional valve controllers and came across SMC VEA250 controller... bought one, connected a 24v power supply to it, cut the plug on my valve and connected the coil to the board, rigged up a 10k pot to the input and after a bit of fiddling I could manage to control the cylinder backwards and forwards, faster and slower by adjusting the pot backwards and forwards faster and slower...


Now, I am not 100% sure i am doing it all right just as yet as the ceramic resistors on my controller board are going quite hot which i find surprising and the cylinder moves slightly faster going backwards than going forward ( NO LOAD).. Further tests to carry...

Assuming that my setup will work this way and I will upload pictures and videos of what I am doing, my question to the community is, how can i link simtools to my board.

from the research I have done, i believe that a Digital pot ( MCP4131) connected to an Arduino will allow me to control the cylinder with digital signal... Is this accurate?

If so, what would be the next step then?

Anyone that could help me on the project I would be rather appreciated...

Thanks you all

Marco

@Marco Dias
I don't have the time to reply to your pm but l will when l get time.
Anyway here is something to think about.... your 4 solenoid valves consists of 3 for the axis movements and the 4th is most probably a dump valve.
Dump valve would be used to either park the capsule so you can get in/out or just for relieving pressure during shutdown.

Hi

I know what the valves do.
You correct. The fourth valve initiates the pressure so the other can operate.

I have no queries at the moment on the workings of the mechanical bits is just on the electronic side of things and controlling..

'Anyway. I will appreciate if you do get time to help

Cheers
M

It looks like the amplifier would want a PWM signal to control the valve, connected through the "outside command signal" input.
It specifically states that you either have the pot or signal, not both. In terms of the resistor getting hot, the manual states that it will do so normally. Getting too hot could be an issue of your coil impedance not being matched to the impedance of the amplifier (13 - 18.5 ohms @ 1 A full scale deflection). it would seem that the SMC VEA250 is not a controller but an amplifier. Your controller will need to supply a given PWM% for a given solenoid position. In hindsight the VEA252 would have been preferable as it comes with a built in feedback circuit.
http://stevenengineering.com/Tech_Support/PDFs/70PCVEA.pdf

Hiya

Thanks for your reply and time.

Yes, I can see that now that you pointed it

many thanks. I can try and measure impedance.

Can i measure the impedance of the coil whilst is working? can it be done with a standard multimeter?

In reference to the VEA252, i did look into it but i am not sure that this feedback would be of any interest to me. my hydraulic actuators actually have a device attached to it with will give me a 0-10v feedback based on it's position.

I have posted details about these devices earlier in the thread including /pictures of my space shuttle...

I will be bringing all the components pictures etc, back into the thread now that i have decided to take on the project.

I will try and make a video of me operating the cylinder with the pot and hopefully it will become helpful on the quest

I have ordered a MCP4131 Digital Pot. the idea is to control the digital pot via the Arduino and wire it directly to the pot contacts.

is this a good way to do it or am I going the longer route here

Ma y thanks for your time

Right..

My mcp4131 digital pot has arrived

Rigged it up to a uno using th following tutorial and code, and I can measure with my meter the resistance looping from o to 5k between wiper and the other terminal. Tomorrow going to connect to the vea250 and I am hoping the arduino will be controlling the actuator by itself

http://www.learningaboutelectronics.com/Articles/MCP4131-digital-potentiometer-circuit.php


Now my worries and questions.


1) I can also measure a voltage on the pot pins. Could this be a problem? The vea250 states a pot OR a 0-5v signal
2) how can I control 3 pots on the same arduino using this example or Other?
3) how can this code be adapted to work on sim tools..
'Would love anyone that could help me as otherwise it may mean months of learning and testing...

Cheers everyone

M

So, me and my rushing into things just blew up my SMC controller...

Looks as I need to buy a load of them. Just hope the valve coil itself didn't fail as it could
Be the end of my project if I actually damaged the valve.. fingers x

So, it was working but getting hot with the standard pot, I rigged up the mcp4131 with the arduino and sample Program, started moving the cylinder, slowly, then retracted the cylinder then 3 minutes later smoke started coming out of the board... from wht it looks a large transistor or triac or something...

Now the manual pot doesn't work

It really gone hot... as a matter of fact, I don't think it was the resistors getting hot, I think it was this transistor...

AnywY, I have 2 more boards en-route and going to try again...

This time I will measure what resistance the pot has when is working and write a program to replicate the same range...

See what happens...

Will update next week... so if there is anyone following this.. hope there is as othwrwise I am talking to myself... ;-)

M

Was it the arduino or the amplifier that blew?

1) Yes ONLY have either the pot or a PWM signal coming in to the control input. Both pot and PWM provide a 0 - 5v signal when read on a multimeter. Having both connected will act as one reducing the voltage of the other, like having a double voltage divider.

2)Technically you don't want to control the pots at all, just supply the input with PWM and get rid of the pots.

3)USE SMC3 and use the 3 PWM channels provided, although it will need positional feedback in a 0 -5v range. (I have written code to convert pulse counts from an incremental encoder into a 0 - 5V range)

4) Youtube about what PWM is

5) USE the onboard LED on the arduino and control its brightness with PWM, Read the analogue voltage as you change the PWM duty cycle. Compare this to a LED controlled by a potentiometer.
Now you will understand why PWM acts like a POT when used as an input to the controller.

@Marco Dias
here is a simple drawing of a control for testing +/-10v control valve.
Disconnect batteries when not in use as it draws current through the pot and will flatten your batteries
You can also use 9v batteries.
Set the voltage you want via the pot monitoring voltage with a multimeter. Button is there for safety.
Push button to send signal, release button to stop


I'm not really sure where you are headed with the SMC controllers.
You need to draw up a plan of what you need/want to do, without a plan you are going to be wasting a lot of money.
To me all you really need is a signal conditioner and rufus' smc ardinio code(maybe modified depending on type of signal cond you use).
Easiest wäy I can think of doing it is to mod smc to output 0-50-100% pwm with no dir. Send pwm to a +/-12 op amp and bobs your uncle...

The amplifier