[artificerjon]

It's a bit premiture but I think I have at last had sucess making a pcb to Lucas' layout, many thanks for that.

I have a question about the power supply/source, what voltage and current capacity would be recomended ? I intend using a NEMA 17 motor to drive a Sherline table via a PminMO L297/8 driver card. The motor is an 8 wire 4.6ohm, 1A per winding with a 'rated' voltage of 4.6V. I anticipate connecting each pair of windings in series, i.e. to give 9.2ohms, 9.2V, 1A at rated voltage, is this the recommended way ?

Any help would be most welcome, I will post some pictures when I am a little further advanced.

Jon'

[mp3]

If you want the stepper motor to drive the table to give the highest possible torque at the highest speed, connect the windings in parallel mode and set the L298 current limit to 2A per winding. Use a supply of about 24V with about 3.5A capability. The winding voltage will be limited to a safe value by the driver current limit (switching transients are absorbed by the output diodes.) You want the lowest inductance from the winding connections to get the highest speed and torque. You get the same torque at low speed from the series winding, but the highest inductance, which limits the rate of change ow current at high stepper clock rates and hence reduce the available torque.

[artificerjon]

I am about to start building the power supply which I had hoped to build into the same case as the electronics but now suspect that might not be possible. The answer to the next question will determine that, does the power supply NEED to be smoothed or is raw full wave rectified OK to feed both the indexer board and the driver boards ?

Is there any advantage (or disadvantage) in smoothing (with some meaty capacitors) the power supply output apart from raising the average dc voltage ?

Jon'

[rooies13]

@ Kwackers

Do you have the sourcecode for Ver2.12?

Kind Redgards

[makinaci22]

Which program will use the compiled code. code fails to compile when I

Sorry bad english .

[kwackers]

@rooies13: I do, it's just not public.

@makinaci22: The code was built with Hi-Tech Compiler. The version I've used is fairly ancient so I can't comment on using newer versions.
(It should be fairly easy to port to another compiler.)

[rooies13]

Okay MR Kwackers

Can i PM you my email address?

Regards

[arvidj]

I think the topic has been suggested several times but I have not been able to find guidelines in this thread.

What would experienced users recommend for motor torque values ... which will eventually guide a new builder in selecting a motor [size, stacked, etc] for ...

A 4 inch rotary table?

A 6 inch rotary table?

An 8 inch rotary table? (This is the one I am interested in but included the others in an effort to gather the informaiton in one place)

A 10 inch rotary table?

A 12 inch rotary table?

Thanks,
Arvid

[arvidj]

Updated manual and new HEX file

...

Also a new HEX file. This file has NO extra functionality so is of no interest to most - but it DOES (in theory) work with the 18F4520, the same HEX file should also be capable of being used on a 18F452 - although I should point out I've run out of spare 452's and so haven't tested it...

If there are any problems let me know...


(Thanks to Marty and Lee for taking the time to figure out why the code didn't work properly on the 4520.)

Has anyone confirmed that 2.12c will work with the 4520? I am in the process of ordering parts and would prefer to order the 4520 rather than the 452.

Thanks,
Arvid

[craynerd]

Arvidj - I have a working controller with a 18F452: Raynerd.co.uk » Blog Archive » CNC Rotary Table Final Video
and I have just blown the code to a 18F4520 . The display works just as it should but unfortunately the controller doesn`t move! I then reverted back to the 452 and it worked as expected!

Very strange but I have a limited knowledge of electronics and microcontrollers and so I can`t tell you why. It is a shame however because I am building 2 new controllers, another for me and one for a friend and I have some spare 4520s which I was hoping to use up!

If you have any idea why this might be happening then please do let me know as I too would prefer to use the 4520s.

Chris

[doorknob]

There is a Microchip document that identifies considerations for migrating from an 18F452 to an 18F4520 at:

http://ww1.microchip.com/downloads/e...Doc/39647a.pdf

(table 1, especially) but it would take some intensive study of the code and programming environment to figure out what impact there might be, so I would be hesitant to make any guesses.

[arvidj]

There is a Microchip document that identifies considerations for migrating from an 18F452 to an 18F4520 at:

http://ww1.microchip.com/downloads/e...Doc/39647a.pdf

(table 1, especially) but it would take some intensive study of the code and programming environment to figure out what impact there might be, so I would be hesitant to make any guesses.

I have loaded the hex code into MPLAB and have taken a quick look at what the initial confifuration bits are if the device is defined as a 452 and then as a 4520. A very quick look suggests that the 4520 is configured as "defaults" which is suggested to be the backwards compatible mode.

Obvously the configuration can be changed in the code but without the source there is little that can be done to move the project forward to a new processor base.

Arvid

[Marty_Escarcega]

I have loaded the hex code into MPLAB and have taken a quick look at what the initial confifuration bits are if the device is defined as a 452 and then as a 4520. A very quick look suggests that the 4520 is configured as "defaults" which is suggested to be the backwards compatible mode.

Obvously the configuration can be changed in the code but without the source there is little that can be done to move the project forward to a new processor base.

Arvid

Arvid. Lee Studley took.the original codes and modified it to work with the newer processor. I believe Steve posted the new file to program the chip. Marty

[arvidj]

Arvid. Lee Studley took.the original codes and modified it to work with the newer processor. I believe Steve posted the new file to program the chip. Marty

Marty,

In my post from a few days ago I indicated that back in March Steve provided this information ...

Updated manual and new HEX file

...

Also a new HEX file. This file has NO extra functionality so is of no interest to most - but it DOES (in theory) work with the 18F4520, the same HEX file should also be capable of being used on a 18F452 - although I should point out I've run out of spare 452's and so haven't tested it...

If there are any problems let me know...

In an effort to determine how accurate "should also be capable" was I asked ...

Has anyone confirmed that 2.12c will work with the 4520? I am in the process of ordering parts and would prefer to order the 4520 rather than the 452.

Thanks,
Arvid

Chris responded, regretfully with a less than promising experience ...

Arvidj - I have a working controller with a 18F452: Raynerd.co.uk » Blog Archive » CNC Rotary Table Final Video
and I have just blown the code to a 18F4520 . The display works just as it should but unfortunately the controller doesn`t move! I then reverted back to the 452 and it worked as expected!

Very strange but I have a limited knowledge of electronics and microcontrollers and so I can`t tell you why. It is a shame however because I am building 2 new controllers, another for me and one for a friend and I have some spare 4520s which I was hoping to use up!

If you have any idea why this might be happening then please do let me know as I too would prefer to use the 4520s.

Chris

As I see it this suggests that either (a) Chris did not use 2.12c or (b) the board that Chris is using is not compatible with 4520 chip or (c) the board that Chris is using is not compatible with the 2.12c software or (d) 2.12c does not work with the 4520 chip.

I am just trying to figure out which one of the above scenarios is in place.

Of course I can simply order 452's from Mouser and be done with it. I am more concerned about the "maturity" than I am the cost. A few buck for the processor is nothing compared to the price of the entire project.

On a different topic I was just thinking of the other things that might be possible if the source code were available in a way that would protect Steve's interest in it. Maybe an NDA with selected individual or some other type of agreement that would protect Steve and his intellectual property, allowing him to retain all of the rights to the changes, complete control, etc.

Little things that even Steve have mentioned like recompiling to allow 32 bit integers, or different processors, etc. -- stuff that he does not have time to address but a selected few might be able to resolve and make available to Steve for distribution if he so chooses.

Arvid

[arvidj]

...

As I see it this suggests that either (a) Chris did not use 2.12c or (b) the board that Chris is using is not compatible with 4520 chip or (c) the board that Chris is using is not compatible with the 2.12c software or (d) 2.12c does not work with the 4520 chip.

I am just trying to figure out which one of the above scenarios is in place.

...

I see on Steve's website the parts list WorldOfWard :: Parts List has both the 452 and the 4520 listed so I am thinking that (a), (b) or (c) might be the case. But without anyone confirming that they have 2.12c working on an a 4520 and how they made that happen we will not know for sure.

Arvid

[kwackers]

Hi guys, apologies for my tardy response.

I only ever gave the 4520 code Lee originally sent a superficial test. I do however have a later .hex file from Lee that I haven't had chance to test.
I've attached it to this post but please note that it's 4520 only and won't work on a 452 also that I haven't tested it at all...

If someone fancies trying it and letting us all know if it works that'd be cool.
If it doesn't then I'll see if I can find some time this weekend to build and test it.

Cheers,
Steve.

[arvidj]

Hi guys, apologies for my tardy response.

I only ever gave the 4520 code Lee originally sent a superficial test. I do however have a later .hex file from Lee that I haven't had chance to test.
I've attached it to this post but please note that it's 4520 only and won't work on a 452 also that I haven't tested it at all...

If someone fancies trying it and letting us all know if it works that'd be cool.
If it doesn't then I'll see if I can find some time this weekend to build and test it.

Cheers,
Steve.

Steve,

I appreciate your taking the time to continue to work on this. After all, it is not your full time job. It is actuallly worse than a job because you are not getting paid to support the project. Thanks!!!

To moderate expectations ... I am in the process of ordering the parts from Mouser [a good parts house here in the US] and therefore will not be able to test anything in the near future. Hopefullly Chris will be able to test the new code before then. In any case I will order both devices and we will eventually get to the bottom of this.

Thanks,
Arvid

[makinaci22]

Hello my rotarytable 1:40 Would not edit the code hex file to help ... bad English Sorry

[cjsamples]

I am sure you get tons and tons of questions about your table. I bet it has turned into a part time/full time job. Great work on your table. I think Khalid made a very impressive video with your controls.
I am having trouble understanding what the limit1/2, sense, ack and gnd do and where they need to be connected. I am assuming they need to be connected to the driver but the wording doesn't seem to match up. Most of the drivers have other wording and not sure I completely understand it. I need to be able to get my head around it before I can accurately purchase components to build it.
Would this type of set up be what I should look for?
Nema 23 stepper motor ,76mm,268OZ-In + matching driver DM542 | eBay
I could purchase the gecko equipment, but price would be higher. I am a hobbbist and try to keep the price down on my "projects".

Thanks for all of the work and time you have put into this as I know tons of people have been inspired to build something just out of their reach and ability.
Chris

[kwackers]

Hi Chris,
Driver and motor look good - better than the one's I use!

With regards the wiring, limit1/2 are simply limits - they can be connected to a switch one for clockwise and one for anti-clockwise. Unless you have a reason to do this though then simply leave them unconnected. (Both can also be connected together and hooked to a switch to 'lock' the device).

Similarly sense and ack are for communicating with other devices - either the same or CNC control systems. If you don't want to do this then leave them unconnected.

The only wires you're interested in are the step and direction, looking at the eBay link you posted, the step would connect to the pulse input and direction to the dir input. You should consult the wiring diagrams that will come with the driver but I'd guess these should be connected to the + inputs for these and the - inputs connected together and hooked to the gnd connection.

Other than that you may need to hook the enable up (although I wouldn't recommend hooking it to the rotab controllers enable, I have some similar looking drivers that don't need the enable connecting). Set the appropriate current on the driver and set the steps per rev to 400 and you should be good to go.

Hope this helps.
Steve.