New Centroid Teknic Clearpath officially supported configurations

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Re: New Centroid Teknic Clearpath officially supported configurations

Post by cnckeith »

Dave_C wrote: Sat Mar 06, 2021 4:20 pm Yup, clear as mud!

Dave C.
ok, simplified explanation: think of 'open collector' as a switch, just like any other switch the voltage the switch is switching is determined by what YOU feed it. :D The Acorn open collector step and direction output can be supplied with 5 volt DC, 12 volt DC and 24 volts DC this allows the Acorn to connect to a wide variety of drives and in the clearpath case use the optimum voltage that is most compatible with the drive for the best performance.

Here is a post explaining open collector in more detail.

viewtopic.php?f=63&t=1699

we always strive to provide the best performance recommendations for a wide variety of popular drives. we test each and every drive with Acorn. We do this work and publish the results as a service to the DIY community , we are spending time and energy providing support for products that we do not make or sell so you the user have a good experience with setup and configuration and so your machine tool performs well with our products when used in conjunction with these drives. Just like our CNC software and hardware products which we are constantly improving we also update and create new support documentation and configuration hookup recommendations, this thread with these revised Clearpath hookup recommendations is an example of that.

check out marty's video series on his Clearpath Acorn project here.
viewtopic.php?f=60&t=5389
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carboncymbal
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Re: New Centroid Teknic Clearpath officially supported configurations

Post by carboncymbal »

Dave_C wrote: Sat Mar 06, 2021 4:20 pm Yup, clear as mud!

Thanks for publicly trashing me for trying to help! It wasn't clear that you had changed the power supply to 5 vdc as most of us who used the terminals were used to it being 24 vdc.

I won't try to help any more nor will I be purchasing any more products from Centroid! EVER

Dave C.
Dave,

I appreciated your attempts to help. I actually thought the same as you. Additionally, I have made errors in my recent attempts to help as well.

I think I saw all of the original Interactions here before edits were made. I think a statement as direct as “ Dave, hello. this statement is not true. :D” doesn’t qualify as trashing you publicly. I would say your prior comments are equally direct “ Neither of the drawings above are for 5 VDC because they connect to the screw terminals and not the DB25

Dave C.”

My personal opinion (not that it should matter to anyone) is that the content and tone of both your comments and CNCKieth were both clear, direct, and appropriate.

I hope you consider staying, I have no doubt that you have a lot of valuable experience and knowledge that many can benefit from.
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Re: New Centroid Teknic Clearpath officially supported configurations

Post by tkbot47 »

I'm still with Dave C's original concern about this. Many of us were wired with 1K resistors going to 24v, per both Centroid schematics and Teknic recommendations. Then, in recent posts, Teknic said that 1K was intended for 5v pullup, and that 10K should be used for 24v, mostly because of current draw and heating of the resistor, and their SDSK manuals were being changed to reflect that. Now we are told to run 5V with 100 instead of 1K ohm, but use a big enough wattage resistor to minimize heating. Why is 1K no longer OK for 5v as originally stated, and why is 24v with 10K no longer OK? For those of us who just changed to 10K at 24V, are we OK leaving it there? If one runs other than this latest recommendation, is there a danger to the Acorn board or it's warranty?
Still confused.
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Re: New Centroid Teknic Clearpath officially supported configurations

Post by RogDC »

TKBOT47
I don't think the change will damage the Acorn from the other threads discussing this issue. The previous Centroid provided Schematic for SDSK's used a +24VDC supply voltage for the Input A+ & Input B+ and the resistor went between these inputs to the motor to the Step (Input B-) and Direction (Input A-)respectively. Many of us have wired our systems up utilizing this schematic. Depending on which version of Teknic manual was referenced, a 1K or 10K resistor was called out.

The latest supported schematic is now recommending a change to +5VDC for the supply voltage to Input A+ & Input B+ for the SDSK's, and a change to the resistor value to 100 ohm 1/2Watt or greater for +5VDC circuit voltage for Step & Direction, and I presume the 1K ohm 2Watt resistor mentioned in the other threads are still valid for the+24VDC supply voltage to inputs A+&B+. To address the timing issue identified subject to the +24VDC supply voltage, and the +5VDC voltage does not experience the timing issue is likely the reason for the supply voltage change.

Tom T. Can verify, but it sounds like this was sorted out using test equipment most of us likely do not have and would be costly and has been validated for the correct values to minimize noise/EMI in the system and completed circuits utilizing an Acorn and provide the best signal to the SDSK's.

viewtopic.php?f=60&t=5389&p=47069#p47069
viewtopic.php?f=60&t=3694&p=47138#p47138
viewtopic.php?f=60&t=5400&p=46583#p46583
carboncymbal
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Re: New Centroid Teknic Clearpath officially supported configurations

Post by carboncymbal »

tkbot47 wrote: Sun Mar 07, 2021 12:55 am I'm still with Dave C's original concern about this. Many of us were wired with 1K resistors going to 24v, per both Centroid schematics and Teknic recommendations. Then, in recent posts, Teknic said that 1K was intended for 5v pullup, and that 10K should be used for 24v, mostly because of current draw and heating of the resistor, and their SDSK manuals were being changed to reflect that. Now we are told to run 5V with 100 instead of 1K ohm, but use a big enough wattage resistor to minimize heating. Why is 1K no longer OK for 5v as originally stated, and why is 24v with 10K no longer OK? For those of us who just changed to 10K at 24V, are we OK leaving it there? If one runs other than this latest recommendation, is there a danger to the Acorn board or it's warranty?
Still confused.
I'll provide my opinion till a response comes along from Centroid or Teknic.

To me it seems like you are asking 2 questions.

1. Why has the manufacturer recommended solutions changed over time? Including multiple changes in the last several weeks?
2. Are systems operating with any of the prior configurations at risk?

Here are my thoughts on those 2 questions.

1. Teknic's guidance on this has been incorrect in the past. Why? The only thing is I can say is that people and companies make mistakes or don't have the ability to consider all use cases. Fortunately for us, Centroid and Teknic have apparently discussed this particular issue and tested it now, which is great.

2. The purpose of the pull-up resistor is to drive the signal to the "high" state, in the case of the old advice, this would be +24v. Acorn's open collector system essentially acts as a switch to provide a path to common (~0v). without a pull-up resistor, the signal may not be a proper square wave. That basically means that the transition from low to high may be unpredictable and inconsistent, likely contributing to the step input timing error many acorn users have experienced with the Clearpath motors. You can think of a pull-up resistor as a constant "leak" that makes the resting state of the control circuit high. The leak is slow enough that when the acorn flips the switch to connect the signal to common, it overcomes the leak and still sends a "low" signal. Acorn open collector outputs are rated at 50ma. If you had the lowest suggested resistor of 1K for a 24v system, it would have provided a current of 24 mA, Clearpath takes another 12 mA, that puts you at 36 mA, still well within the capability of the Acorn outputs. The current is even lower with a 10K resistor.

Every individual system can be different, at the end of the day, as long as you are within the voltage and current limits of all components, you don't need to change anything if your system is reliable. There have been reports of systems degrading over time for some reason (systems that have been in place for 6-12 months before experiencing step input timing errors), so if you ever have issues you know have a plan to address them.
Last edited by carboncymbal on Sun Mar 07, 2021 2:17 am, edited 1 time in total.
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Re: New Centroid Teknic Clearpath officially supported configurations

Post by carboncymbal »

It seems to me that a 100 ohm resistor on a 5v system would have the acorn outputs sinking a current 58 mA. This is above the maximum stated in the Acorn user manual. Is this correct?
Clearpath Input Current Draw.PNG
Acorn Specifications.PNG
Thanks,
Clay
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Re: New Centroid Teknic Clearpath officially supported configurations

Post by tkbot47 »

carboncymbal wrote: Sun Mar 07, 2021 2:14 am It seems to me that a 100 ohm resistor on a 5v system would have the acorn outputs sinking a current 58 mA. This is above the maximum stated in the Acorn user manual. Is this correct?

Clearpath Input Current Draw.PNG
Acorn Specifications.PNG

Thanks,
Clay
This is what I'm talking about. First, per Teknic, we were at 1K for both 5 and 24v, then it was recommended (2 wks ago) for heating to go to 10K at 24v. It was also pointed out that this would minimize sinked current through the Acorn outputs. Then in one of the links Teknics said oops, now I recommend 1K again for both 5 and 24V, but use a 2W resistor at 24v to dissipate a 0.58W and sink 36ma through the Acorn outputs. Now we have the recommendation solution that would only dissipate 0.25W through the recommended 1/2 watt resistor, but evidently sink 58ma through the recommended 50ma circuit. Seems to still raise some concerns - as carboncymbal says - is this correct? Does the circuit really need to draw this amount of current to form an adequate signal for the Clearpath? Would a 220 ohm resistor work OK and yet draw 1/2 the current?
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Re: New Centroid Teknic Clearpath officially supported configurations

Post by carboncymbal »

tkbot47 wrote: Sun Mar 07, 2021 12:46 pm
carboncymbal wrote: Sun Mar 07, 2021 2:14 am It seems to me that a 100 ohm resistor on a 5v system would have the acorn outputs sinking a current 58 mA. This is above the maximum stated in the Acorn user manual. Is this correct?

Clearpath Input Current Draw.PNG
Acorn Specifications.PNG

Thanks,
Clay
This is what I'm talking about. First, per Teknic, we were at 1K for both 5 and 24v, then it was recommended (2 wks ago) for heating to go to 10K at 24v. It was also pointed out that this would minimize sinked current through the Acorn outputs. Then in one of the links Teknics said oops, now I recommend 1K again for both 5 and 24V, but use a 2W resistor at 24v to dissipate a 0.58W and sink 36ma through the Acorn outputs. Now we have the recommendation solution that would only dissipate 0.25W through the recommended 1/2 watt resistor, but evidently sink 58ma through the recommended 50ma circuit. Seems to still raise some concerns - as carboncymbal says - is this correct? Does the circuit really need to draw this amount of current to form an adequate signal for the Clearpath? Would a 220 ohm resistor work OK and yet draw 1/2 the current?

I do Indeed look forward to more information from Centroid on this. I think Richards opinion where he talks about using a scope to analyze the square wave to identify an appropriate trials for is the most detailed and logical answer I have seen so far. I’ll be checking my systems with a scope (including one currently set up with a 10k resistor on 24v.)

viewtopic.php?f=60&t=5400&p=46885&hilit=Shark#p46885

-Clay
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Re: New Centroid Teknic Clearpath officially supported configurations

Post by cnckeith »

- the max current rating is for all the chip channels combined, the clearpath to Acorn is not using all of them so no risk at exceeding current ratings.

- 1/2 watt 100 ohm at 5 volts runs 'cool', 1/4 watt will run hot (which is ok, just easy to go to 1/2 watt and not have it be hot)

- the 5 volt 100 ohm combo produces the best performance results with the Clearpath. test results show that it is the best way for fast reliable connection to Clearpath.

see detailed test results attached.
Attachments
Clearpath_input_test.pdf
(150.2 KiB) Downloaded 96 times
Need support? READ THIS POST first. http://centroidcncforum.com/viewtopic.php?f=60&t=1043
All Acorn Documentation is located here: viewtopic.php?f=60&t=3397
Answers to common questions: viewforum.php?f=63
and here viewforum.php?f=61
Gear we use but don't sell. https://www.centroidcnc.com/centroid_di ... _gear.html
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Re: New Centroid Teknic Clearpath officially supported configurations

Post by tkbot47 »

cnckeith wrote: Sun Mar 07, 2021 1:34 pm - the max current rating is for all the chip channels combined, the clearpath to Acorn is not using all of them so no risk at exceeding current ratings.

- 1/2 watt 100 ohm at 5 volts runs 'cool', 1/4 watt will run hot (which is ok, just easy to go to 1/2 watt and not have it be hot)

- the 5 volt 100 ohm combo produces the best performance results with the Clearpath. test results show that it is the best way for fast reliable connection to Clearpath.

see detailed test results attached.
Keith,
Thanks for this detail - it is very clear. I have a couple questions just to further clear things for me:

1. Have you tested at 400khz? I am using that because of a 4th rotary axis setup that has a 15:1 gear reduction, and wanted to maximize steps/rev for that setup. I haven't seen errors yet with no resistors because the wire is the std Teknic 10 ft cable, but my longer cables (25 ft) are also at 400khz (can't set different channels at different freq) with 1K resistors at 24v (2 channels of S and D are 25 ft, X and Z). If I change the longer ones to 100 ohm at 5V, would I be OK?

2. In your testing, did you try something a little higher than 100 like 180 or 220 to try to reduce the current a bit?
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