motor moment project

[ronv]

You may need to experiment with the values, but something like this might work.

 

[perjan6666]

thanks but i need something to adjust from zero to max not only 4 different values

 

[perjan6666]

hello again i have done a little research about torque measurements and com up with this:
**broken link removed**


or maybe a cheaper edition, i believe that it is necessary with a maximum of 200 nm in measurements just to be safe.
and again i have a problem, little experience with pls or computer controlled stuff.

can anyone maybe come up with a circuit board witch i can select the newton meters that i want the motor to apply to the chains?? if its more easy ti can just be a pot to control the torque. and if i want to read the torque i can use this: **broken link removed**

 

[perjan6666]

hello is there anyone in this forum that can help me???

i was looking on youtube and discover this https://www.youtube.com/watch?v=iOINcW8BP3w
a Digital Potentiometer if i have a rc-led circuit between my switches and the Digital Potentiometer it will easily do what i want

can someone please help me to design this circuit

 

[alec_t]

maybe i explained wrong, i meant that it will change the milliamp by 0,5 ant then Wait the time delay before repeat the progress as long as there is a voltage applied to the input

Ah, that's a different story. It rules out a wholly analogue solution but looks doable with discrete logic and counters (though a micro would be better). I'm not sure a digital pot would be any simpler.

it would be nice to have the opportunity to change how much the milliamp changes at the time also ex. from 0,1 ma to 3,0 ma

Nice, but slightly more complicated.

if i have a rc-led circuit between my switches and the Digital Potentiometer it will easily do what i want

I don't see how.

I'll have a think.

 

[alec_t]

it would be nice to have the opportunity to change how much the milliamp changes at the time also ex. from 0,1 ma to 3,0 ma

0.1mA represents a speed change of 0.5% of full speed. As I said, I have no experience of industrial control but I feel that even that may be too big a change and the motor mount will be swinging rapidly to and fro between the inner switches as the speed tries to adapt. The switches are likely to fail early if they operate too frequently.
That said, I now have a 4-switch design roughed out for providing bursts of 1 to 9 (selectable with a jumper) steps each of ~ 0.1mA, the bursts repeating at selectable ~1-20 sec intervals while a switch is closed. I'll tidy it up and post it in the next day or two, but it will be a schematic for a skilled technician to work from and to vet for safety issues; it won't be a constructional article.

 

[alec_t]

Here's the schematic as advertised. It's not ideal, but could be a starting point for someone with the necessary skills to interpret it and build a prototype circuit from it, if they wish. I deliberately have not included such details as IC pin-outs, D/A details and construction, because of safety concerns: if you can't work from the schematic your skill level may not be enough to build this safely and you should refer it to a competent technician locally. If built, the circuit should be subjected to thorough bench-testing without a motor connected.
For image clarity reasons I have posted the schematic in two parts. Stage 1 drives stage 2.

Operation
In stage 1 four ground-referenced switches In1-In4 selectively control transmission gates U2a-d via inverters U1a-d. Transients/interference on the switch leads are suppressed by TVS devices TVS1-4, chokes L1-4 and capacitors C1-4.
A clock oscillator is formed by R5, C5 and Schmitt inverter Uie, with feedback via whichever transmission gate is open (conductive) and via Pot1 or Pot2 as appropriate. R5 sets the minimum oscillation period at ~1mS.
The oscillator output clocks both a 12-stage counter U4 and a decade counter U5. U4's Q10 output pulses at ~1Hz (if double or half that were to prove useful then the Q9 or Q11 output could be selected instead by a jumper or switch).
Each Q10 pulse resets (via C7, R7) counter U5, which proceeds to count the 1mS clock pulses. When a preset count (1-9) is reached (determined by jumper selection of a suitable output of U5) the U5 clock input is disabled. NAND gtes U3b, U3c enable the preset number of 1mS pulses to pass to the next stage. R6/C6 slightly delay the clock pulses into U3c to overcome a glitch due to inherent IC response time.
U3a gives an up/down count control signal for the second stage.
In the second stage U7/U8 together form an 8-bit counter clocked by the gated 1mS pulses from the first stage. An 8-bit D/A converter provides an analogue output from the counter value. The Up/down signal from stage 1 determines the count direction.
To prevent count wrap-around, U9 detects if all 8 bits are '1' when counting up, and U10a,b detect a count of zero when counting down. Either detected event disables further counting via gate U6a.
A power-on reset function for U7/U8 ensures the count starts at the '4mA count'.
R10/R11 scale the D/A converter output to a value used as a reference for a comparator formed by op-amp U13. U13 controls the current through R13, hence through the control loop, so that the voltage dropped across R13 equals the reference.

[Simulation files are attached, but need model files CD4000.lib, CD4066.sub, potentiometer.sub, LM324NS.mod to run]

 

[perjan6666]

thank you so much and sorry for wasting your time but i think this is little to advanced for me and also difficult to troubleshoot if something don't work anymore.

do you think this circuit ( https://farm4.static.flickr.com/3037/3068096606_be9cecc840.jpg?v=0
here is a youtube video of the functionality of it https://www.youtube.com/watch?v=K74FG5LAjso )
can drive this circuit https://www.youtube.com/watch?v=iOINcW8BP3w and this is connected to the pot connections on the frequency converter

if i use 2 of those PWM 555 circuits one for adjusting the pulse frequency on the outer switches and one for adjusting the pulse frequency on the inner switches (fine tuning longer brake between pulses)

after what i understand the digi-pot changes one step each pulse?

maybe you can help to make a wiring diagram on those together?

 

[alec_t]

The digi-pot linked to is a 100-step one, so each step will result in a 1% change in motor speed. Do you think that will be small enough for smooth control?
It is not clear from the datasheet for that digi-pot what state (resistance setting) it will start in following a power failure or brown-out. It could apparently be either the setting when power was lost or the setting stored in its non-volatile RAM on a previous occasion. That uncertainty would concern me. I think it would be better for your application if it always reset to zero.

 

[perjan6666]

babe but when the conveyor is stopped it always start at the same speed as when stopped so i think it will work if the value is stored,
and when the speed is adjusted today you can choose only hole numbers between 15 and 50 and that is only 35 steps.

i didn't say i want to use this particular circuits but similar. maybe more steps on the digi-pot possible
and i only need to adjust the pulse frequency in the 555 chip not the pulse length so a fixed resistor can be placed instead of the 2 pots

 

[alec_t]

maybe more steps on the digi-pot possible

The only digi-pots I could see listed with more steps use an I2C or other more complicated interface for setting the value and would need a micro to control them.

when the speed is adjusted today you can choose only hole numbers between 15 and 50 and that is only 35 steps.

Is that referring to the main motor or the helper?

i only need to adjust the pulse frequency in the 555 chip not the pulse length so a fixed resistor can be placed instead of the 2 pots

I would suggest keeping the 2 pots for pulse frequency adjustment, otherwise you will have to keep swapping resistors until you get the result you want.

I'll work on a revised design.

 

[perjan6666]

the speed options are for both motors same 35 steps

 

[alec_t]

Here's a basic design using a 555 for timing and a WMS7170 100-step digi-pot, based on my interpretation of the digi-pot datasheet (I have no practical experience of using one).
View attachment 65818
Operation
An inner or outer switch, when closed, pulls down the input of a respective gate U1 and so enables C8 to charge via VR1 (for an outer switch) or VR2 (for an inner switch). When the 555 threshold is reached C8 discharges via R5 and the cycle repeats. The mark-space ratio of the resulting pulses from the 555 is at least 99.7:1.
The CS input of the digi-pot U3 is normally held low by R8, so the pulses applied to the INC input step the pot value up or down depending on the Up/Down input. An inner switch signal is diode-ORed (by D1/D2) with an outer-switch signal to derive the Up/Down input signal. A momentary 'Store' switch can be pressed to store the pot value if desired (with a > 99.7% chance of success).
The pot output is buffered by U4 (here an LM324NS, but other rail-to-rail input and output opamps may be preferred). The opamp uses the 24V supply to ensure full 0V to 5V output swing. R9/R10/D7 clamp the output to ~5.6V in the event of opamp failure. The circuit connects in place of the existing 1k speed-control pot.
The circuit input is protected by TVS suppressors, chokes L1-L4 and bypass caps C1-C4. Cables to the switches should be screened.

No attempt has been made to ensure the digi-pot is set at any particular value at power-up or after a brown-out. You should satisfy yourself that that will not present a safety problem before using a circuit built on the basis of this design. Any such circuit should be thoroughly bench-tested without a motor attached.

 

[perjan6666]

you are very good at this and fast do you do this as a living?

it looks like the solution to me can i get the chopping list from you so i can order the stuff for building and testing. if succeeded i will have a professional company to make a few so i have in spear also. its cheap to make and expensive to design
so i'm thanking you so much for your time i can post a video when everything is in place if you want

 

[alec_t]

do you do this as a living?

No, a hobby.

can i get the chopping list from you

We don't even know which part of the world you're in, so can't judge what might be readily available to you. You can Google for the components used. A local technician would be best placed to help/advise.
If you get this built some pics or a video would be interesting.

 

[perjan6666]

i'm from norway i have looked at some stores and it seems like som of the components dont have the same name. but i can call them and ask for simular

 

[alec_t]

Hello Norway!
Here's a revised version with R6 and R11 added in series with VR1 and VR2 to avoid absurdly brief steps.
As the LM324 is a quad opamp I've also added a 4-20mA current-loop stage built around opamp U4b, so you have the option of the voltage output from U4a or the current output from the U4b stage at the added cost of just a few resistors and a transistor.
View attachment 65832
I've attached a component list for this revised version.
I've also attached the .asc file for the LTSpice simulation.

 

[perjan6666]

do u have the files to run sumlation? lm324ns, potentiometer.sub is missing maybe other also

 

[alec_t]

The model files are available from the LTSpice user group at Yahoo.com.
You will need CD400.lib, potentiometer.sub, LM324NS.mod and perhaps a model for a 5.6V zener diode (I cheated and modified the voltage parameter of a model of some other zener diode, but you can delete the zener and simulate the remainder of the circuit).
I did not try simulating the digi-pot accurately....I initially used a CD4024 model with some weighting resistors on its outputs. The asc file I posted shows a dummy digi-pot but doesn't simulate it, so to simulate the voltage drive and current drive stages you will need to provide a swept voltage stimulus to the opamp inputs.

 

[perjan6666]

now i have a scope in the mail so when it arrives i build a test board.
do you think i need a voltage regulator because the measured voltage is 28v DC and it sometimes are lower and higher.
and this CD40106 can i use this? https://www.electro-tech-online.com/custompdfs/2012/07/0900766b80b72404.pdf
and i think i need some help on the wiring of this chip to get the voltage correct and stuff