Stepper Motor Driver Simulation Notes

Q: How to Design Stepper Motor Drive?

Sabretooth 2438I am doing a project which requires us to design Stepper Motor Drive in PLD using Multisim. I am trying to find the theory behind it but I can’t seem to find where and how to start and how should I implement the truth table and kmap. In the question, we have to make two design for Stepper Motor: …stepper-motormultisimtlfong016005#Sabretooth 2438, Ah, you need to read quite a lot before designing something. You might find some of the references in my answer to the following question useful: raspberrypi.stackexchange.com/questions/124791/…. Have a great stepper motor project. Cheers.Now I assume you are trying to use NI Multisim to design a stepping motor driver to drive a bipolar stepping motor. You need to specify the input signals to the stepping motor driver. You might use A4988 microstepping motor driver as a example, though you might only need to implement full and half step mode. So for the A4988 case, the ms1. ms2, ms3 can be simplified to only to ms1 which configs full step if H, half step if L. Like this: i.imgur.com/eE3wueL.pngSabretooth 2438@tlfong01 sorry, but how can I implement it in the sub PLD (Stepper Motor Driver) file, since the only components you have is mostly based on Boolean tlfong016005I don’t understand what do you mean by “since the only components you have is mostly based on Boolean“? Can you give me an example? Or perhaps I can give an example, say, a full adder. For a full adder, you specify the inputs and outputs, of course they are all Boolean, and NIM will implement the full adder for you, using logic gates (combinatorial and sequential components). Do I understand your situation and NIM’s function correctly? Sabretooth 2438@tlfong01 I believe so, I apologize I am still a 2nd years student so my knowledge is still limited, and so far we have covered flip-flops so I am still a bit confused about this project but thank you for the help Edit: in the PLD will I be using the counter or flip flops if you don’t mind tlfong016005Ah, you remind me my long long ago years studying my rusty EE diploma. I learnt about logic gates and binary counters etc. I must confess that even after graduation I still have vague ideas about combinatory and sequential circuits, level and edge triggering, 555 monostable/astable/bistable stuff. I knew K-map very well, and drilled and drilled a lot, because they were favourite exam questions, :). Now coming back to your question. Are you sure your full/half step table is really a K-map? / to continue, …I still remember that K-Map is for combinatory stuff. For sequential things, you need something called a “state diagram“. 🙂 Any way, I need to read again the MicroChip/Iowa prof’s good tutorial on stepping motor, to refresh my memory on the meaning of full/half/microstepping etc, and see if I can suggest a spec for your NIM project. Cheers.This is the Iowa Uni Prof DW Jones’ very good tutorial I read when learning the stuff: homepage.divms.uiowa.edu/~jones/step/an907a.pdf. Perhaps you can also read it and we can use it as a reference of terms when discussing the NIM project. Cheers.Another good reference is this one: How to control unipolar/bipolar stepper/stepping motors such as … , RpiSE 2019apr27, Viewed 887 times raspberrypi.stackexchange.com/questions/97975/…. These two references give the big picture of stepping motors. I usually recommend to first look at the big picture, ie, the woods (all about stepping motors), then the trees (our NIM project on bipolar stepping motor). Of course it is the trees that Stack Overflow suggest us to laser sharply focus. Sabretooth 2438yst 15:23@tlfong01 I am not sure about the k-map, I assumed there should one. All I am looking for is the procedures and how can I obtain the values to make the project workHello tlfong016005@Sabretooth2438 I see. I agree there is some confusion about the full/half step “sequence”. I found it interesting that no one seems interested to give a name to the sequence. If I was asked to give a title or name, I would say something like “Sequence of steps to power/signal to the two coils of the bipolar two coil four leads stepping motor. Of course this is too long winded. Sabretooth 24381let send you the full question that we receivedDesign a half-step sequence stepper motor driver digital circuit. Half-step sequence mode states (combination) causes step angle θ° of shaft rotation in stepper motor (step angle θ=0.9° ).The three modes of operation are shown in Table 1. There are only four states in the full-step sequence and wave-drive sequence. On the other hand, there are eight states in the half-step sequence as shown in table 1. Figure 1 shows the stepper motor driver where it has two inputs and four outputs.If D=0 the sequence will be the sequence in the table from row 1 to row 8 and If D=1 the sequence will be from row 8 to row 1. The second input is the clock input which controls the speed of operation. tlfong01If you would like to suggest a better name, or if you happen to find other tutorials using a better name, you might let me know and we would discuss to agree on a better name. I do think K-map is not very appropriate or a bit misleading. Sabretooth 2438this is for HAlf step@tlfong01 the reason I said kmap because the whole semester we were dealing with truth tableso i assumed kmap will be associated with it tlfong01Ah, the question is good. So other names can be “motor coils drive sequence”, “state diagram” etc. But that is not important. We can for name just use a casual name, say “Half step motor drive sequence” and you might like to propose a better name name later. Sabretooth 24381yst 15:36Just to be clear I have to make 2
Half step and Full stepA Half step is 0.9 angle
and Full step is 1.8 angle tlfong016005Another question. If you read Iowa Uni Prof Jones’s tutorial, you might see him showing a schematic with something called full/half “H-bridge”, usually implemented using NPN/PNP BJT or N/P -channel power MOISFET. A motor driver such as L293D already has this. Now if your NIM has this “H-bridge thing” is the library, then you can directly use it. Otherwise you need to use BJT/MOSFET to implement this H-bridge. Sabretooth 2438Sorry, I couldn’t follow tlfong01Yes, default full step is 1.8 degrees, so half step is 0.9 degrees. This is pretty standard of stepping motors. You might find me using NEMA17 stepping motor which has .8 degree as the standard. Sabretooth 24381do we have that in multisim?all I could find stepper motor phase2 phase*that is connected to the stepper motor driverthat I have to work on it tlfong01Ah, I am talking too fast. So you might like to skim the two references I gave you, focusing on “bipolar”, “two coils”, “two phase”, “four leads/wires”, “full/half step” etc. Then google/wiki “H-bridge”, and perhaps also “L293D”. I will wait for you for perhaps one or 2 days to catch up. Sabretooth 2438yst 15:45honestly compare to you I feel stupid. tlfong01You need to go slowly otherwise you won’t learn thoroughly and remember things hard. Question: what is the dead line? 🙂 Sabretooth 2438it is next month on 13but we also have other assignments coming upso I want to finish it as much as possible tlfong01Well, comparing to me, long long time ago, studying my rusty EE diploma, I think you are OK, at least as smart as me. 🙂 Sabretooth 2438I wish, because of covid we have lack of practical that is why we are learning on Multisimso most of the stuff I am not understanding wellbut managing it barely tlfong016005I see. So deadline is June 13. Another question: Is yours an individual project, or a group project, or is everybody giving the same assignment, and so you guys can discuss on line?Ah, so it is Covid19’s fault. Otherwise you can go to the practical lab, find a L293D and wired up the circuit with a motor, test it, then you can learn well.Anyway, I think you need to learn the full/half bridge theory/operation, never mind BJT or MOSFET. Sabretooth 2438yst 15:52@tlfong01 individual, but we still discuss it in the group but so far now I am the only one who startedok, I’ll do that tlfong01Ha, so you are an early bird. Ah, I missed my locking down afternoon tea. So I will leave you to read the stuff. In the mean time, you are welcome to ask me newbie questions though. Cheers.  5 hours later… tlfong01yst 20:54Now I am skimming the NIM user manual:ni.com/pdf/manuals/…Please confirm if you are reading the same 2009jan (seemingly a bit out of date) version. tlfong016005yst 21:31So I skimmed the user manual and I am not impressed at all, because I don’t find too many high level components in the components database. Below is my wish list:1. Full H-bridge2. DC MotorDC Motor is not important, because you can use two resistors to fake the two coils of a bipolar stepping motor.But the full H-bridge is crucial, because it is the core component of the stepping motor driver. Or can you ask your tutor if there is any H-bridge and / to continue, ... Sabretooth 24381he just gave us this Multisim schematic the one in the forumall I have to do is create logic in the subPLD filewhich is stepper motor drivewhich I believe I have to implement the logic w learned this semsterforgot to mention my course called Digital Devices and Systems EN6020so it is mostly based on logic gates and truth table and bolean expressions tlfong01So you only need to use counters, flip flops, to complete the exercise, no need to design H-bridge or DC motor? Then it should not be that hard. Sabretooth 2438yescounters and flip flops are just only speculationbecause I noticed how the logic worked in the table tlfong01Ha, then you should not worry that much. Sabretooth 24381for half step I am kinda confused a bitin full step it is easy to fin the next stepbut in the half step I didn’t understand why it converted to 0 or 1this is our Learning outcomes:
Demonstrate detailed knowledge in the application of Boolean Algebra to simplify logic circuits.
Apply detailed knowledge and basic skills in the design methodology used to solve combinational logic problems.
Apply detailed knowledge and basic skills in the design methodology used to design sequential logic circuits.
Demonstrate detailed knowledge in identifying elements of a hardware description language. tlfong01yst 21:42Ah, so you don’t understand the half step thing. Perhaps you should read Prof Jones’s tutorial very carefully. Sabretooth 2438just to be clear as possible so I don’t inconvenience you any furtherok tlfong01Ah, you have given me enough info now. You might like to show me the “schematic” in the forum, then I can have a clearer picture. But no hurry at all. Perhaps tomorrow or day after tomorrow. Ah bed time. Call it a day. See you tomorrow or later. Bye. Sabretooth 2438sure, still working on ithave a nice day and thank you for the help tlfong01You are welcome. Good luck. Cheers.  12 hours later… tlfong019:53Just now I visited MS forum and searched for “stepping motor”. Not much I found. This looks good to do further searching, though: forums.ni.com/t5/…. The post was 2013. So I still think NIMS is not very updated. tlfong01600510:10I searched for NIM forum H-bridge and found a couple of posts. Perhaps you can borrow some H-bridge schematics for use in your project.

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  3 hours later… Sabretooth 243813:01is H-bridge is located in logic?because most of the stuff in subPLD files are logic  1 hour later… Sabretooth 243814:14also, does the stepper motor consider synchronous or asynchronous? tlfong01600515:03(1) Well, H-bridge uses components such as power MOSFETs and other logic gates. Perhaps you can check out the guys in the NIM forum playing with H-bridges. I have been playing with Circuit Lab and LT-Spice from circuit design and simulation. But I don’t find simulation very useful. I usually use real components and proto boards and test the real hardware. Perhaps I can find some Ctt Lab’ H-Bridge simulation schematics for your reference.But perhaps your prof can give you the basic schematic with the H-bridge, and you only need to add combinatorial and sequential logic devices to complete the assignment. (2) I think step motor driver is synchronous, otherwise the motor would move out of sync. But I am not very sure.I search Circuit Lab’s simulation schematics and found the following. You can use the link to get the schematic and read it using EESE’s built in Cct Lab tool. But I think you cannot copy and paste to the NIM simulator.circuitlab.com/circuit/y49w33/…

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But you might not need to touch H-Bridge, because your prof has not taught that yet. So you might need to confirm with your prof, otherwise you might be wasting your time.Ah, tea time. See you later this evening or tomorrow. Good luck. Cheers. 

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