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Subject: Emc-users Digest, Vol 125, Issue 35 

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Today's Topics: 

1. Re: output sink of the 667 hall effect? (Chris Albertson) 
2. Re: Plasma Torch Height Control (Klemen ?ivkovi?) 
3. Re: Plasma Torch Height Control (Marius Liebenberg) 
4. Re: output sink of the 667 hall effect? (Gene Heskett) 
5. Re: output sink of the 667 hall effect? (Chris Albertson) 


---------------------------------------------------------------------- 

Although more expensive than the Allegro IC's, Check out the Honeywell 
SNG-QPLA-00, a self contained, quadrature detector based on their hall sensors. 
Checked the Honeywell website, current pricing is $27.00 from Allied or Newark. 
Device is optimized for 12 pitch gears. Been using them in very dirty, and 
noisy environments for about two years now. 
Messge: 1 
Date: Mon, 12 Sep 2016 11:44:33 -0700 
From: Chris Albertson <[email protected]> 
Subject: Re: [Emc-users] output sink of the 667 hall effect? 
To: "Enhanced Machine Controller (EMC)" 
<[email protected]> 
Message-ID: 
<cabbxvhup-3ouck_bg+snyplgb5ehp-wccfksjrynmzmjjjs...@mail.gmail.com> 
Content-Type: text/plain; charset=UTF-8 

I think the RC filter idea would work OK. Gear teach are after all a 
low frequency signal, so a filter made with a cap size for a corner 
freq of (say) 100KHz will keep RF out of the line. 

That said the "correct" way to do this is with a pair of 
driver/receiver chips. If you use RS422 (that is a differential 
signal) you can likely go over a 1/4 mile of trusted pair wire. 

As for wire why not use Cat 6 or better for a machine shop cat-6 
shielded. It is terminated in RJ45 and it's dirt cheap. And has 
enough pairs (4) for your use. 

Also I was reading LinuxCNC docs, it said a spindle encoder needs to 
be quadrature. You need two sensors for that phase A and B plus a 
third for the index. Cat 6 has four pairs so you can use the 4th 
for power to the sensors. 

As I said, the simple RC filter like you suggested can work but the 
"classic" method for use in a shop filled with high power machines is 
to use a differential single as it is immune to common mode noise, 
then use twisted pair in a sealed that is grounded on ONE end only, 





On Mon, Sep 12, 2016 at 10:43 AM, Gene Heskett <[email protected]> wrote: 
> Greetings all; 
> 
> I see by the spec sheet that the allegro 667 gear sensor can sink up to 
> 25 mills. 
> 
> But with 3 such sensors on the end of a long cable back to the breakout 
> board, probably 7 foot by the time I get it routed, I am concerned with 
> the potential for crosstalk noise in spite of putting a bypass capacitor 
> on the encoder itself. 
> 
> This noise would be reduced by a lesser amount of current. So, for those 
> of you using this device, what value is the resistor are you using for a 
> pullup at the breakout board? 
> 
> And if using a piece of idc ribbon cable, it seems to make sense to put a 
> grounded wire between each of the A|Z|B conductors, making that a 7 
> conductor cable rather than a 5. I have around 90 feet of 26 wire ribbon 
> I can split off what I need from. 
> 
> Good idea? Or off the wall & probably will be plagued by noise if I shoot 
> for a 10 milliamp pullup with a 470 ohm pullup, or even 5 mills with a 
> 1k pullup. 
> 
> Time to assemble that motor driver box I believe. 
> 
> Cheers, Gene Heskett 
> -- 
> "There are four boxes to be used in defense of liberty: 
> soap, ballot, jury, and ammo. Please use in that order." 
> -Ed Howdershelt (Author) 
> Genes Web page <http://geneslinuxbox.net:6309/gene> 
> 
> ------------------------------------------------------------------------------
>  
> What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic 
> patterns at an interface-level. Reveals which users, apps, and protocols are 
> consuming the most bandwidth. Provides multi-vendor support for NetFlow, 
> J-Flow, sFlow and other flows. Make informed decisions using capacity 
> planning reports. http://sdm.link/zohodev2dev 
> _______________________________________________ 
> Emc-users mailing list 
> [email protected] 
> https://lists.sourceforge.net/lists/listinfo/emc-users 



-- 

Chris Albertson 
Redondo Beach, California 



------------------------------ 

Message: 2 
Date: Mon, 12 Sep 2016 21:06:28 +0200 
From: Klemen ?ivkovi? <[email protected]> 
Subject: Re: [Emc-users] Plasma Torch Height Control 
To: "Enhanced Machine Controller (EMC)" 
<[email protected]> 
Message-ID: 
<CADO03PqxCD=U9eFya+idN9KT75RDwb1Gxqxc_wZZmN5f7S47=a...@mail.gmail.com> 
Content-Type: text/plain; charset=UTF-8 

I can see some plasma machines have serial interface also ( 
http://forum.robotsinarchitecture.org/index.php?action=dlattach;topic=232.0;attach=335).
 
Also found this thread - 
https://forum.linuxcnc.org/forum/27-driver-boards/21445-rs-485-with-7i76. 
Is serial plasma control over "plasma/serial" component good practice? If 
yes maybe somebody knows is there already such plasma serial component that 
is connected to THC component? Can somebody share or point me to hal/ini 
setup in that case? 

regards 
Zhivko 

On Mon, Sep 12, 2016 at 7:41 PM, John Thornton <[email protected]> wrote: 

> I'd bet it does both and it may even have a output for ark ok... 
> 
> JT 
> 
> On 9/12/2016 8:53 AM, Alexander Brock wrote: 
> > On 09/11/2016 04:22 PM, John Thornton wrote: 
> >> Does is have connections to measure the tip voltage? 
> > I'm not exactly sure, it has a connection named "CNC" and it might be 
> > either an input for starting / stopping the cutting or an output for 
> > measuring tip voltage. 
> > 
> > Best Regards, 
> > Alexander 
> > 
> > 
> > 
> > ------------------------------------------------------------ 
> ------------------ 
> > 
> > 
> > _______________________________________________ 
> > Emc-users mailing list 
> > [email protected] 
> > https://lists.sourceforge.net/lists/listinfo/emc-users 
> 
> ------------------------------------------------------------ 
> ------------------ 
> What NetFlow Analyzer can do for you? Monitors network bandwidth and 
> traffic 
> patterns at an interface-level. Reveals which users, apps, and protocols 
> are 
> consuming the most bandwidth. Provides multi-vendor support for NetFlow, 
> J-Flow, sFlow and other flows. Make informed decisions using capacity 
> planning reports. http://sdm.link/zohodev2dev 
> _______________________________________________ 
> Emc-users mailing list 
> [email protected] 
> https://lists.sourceforge.net/lists/listinfo/emc-users 
> 


------------------------------ 

Message: 3 
Date: Mon, 12 Sep 2016 19:16:04 +0000 
From: "Marius Liebenberg" <[email protected]> 
Subject: Re: [Emc-users] Plasma Torch Height Control 
To: "Enhanced Machine Controller (EMC)" 
<[email protected]> 
Message-ID: <emb745acfd-31cf-4559-99fb-926ac06b624c@marius-pc> 
Content-Type: text/plain; format=flowed; charset=utf-8 

I have one concern about the use of serial interface for THC. The serial 
components are notoriously slow and sometimes are very far behind the 
real-time events. With THC you need very fast and in time movements. 
Unless there is an interface to the Mesa serial channels, I would be 
cautious to implement a design without proper testing as far as latency 
is concerned. 

------ Original Message ------ 
From: "Klemen ?ivkovi?" <[email protected]> 
To: "Enhanced Machine Controller (EMC)" 
<[email protected]> 
Sent: 2016-09-12 21:06:28 
Subject: Re: [Emc-users] Plasma Torch Height Control 

>I can see some plasma machines have serial interface also ( 
>http://forum.robotsinarchitecture.org/index.php?action=dlattach;topic=232.0;attach=335).
> 
>Also found this thread - 
>https://forum.linuxcnc.org/forum/27-driver-boards/21445-rs-485-with-7i76. 
>Is serial plasma control over "plasma/serial" component good practice? 
>If 
>yes maybe somebody knows is there already such plasma serial component 
>that 
>is connected to THC component? Can somebody share or point me to 
>hal/ini 
>setup in that case? 
> 
>regards 
>Zhivko 
> 
>On Mon, Sep 12, 2016 at 7:41 PM, John Thornton <[email protected]> wrote: 
> 
>> I'd bet it does both and it may even have a output for ark ok... 
>> 
>> JT 
>> 
>> On 9/12/2016 8:53 AM, Alexander Brock wrote: 
>> > On 09/11/2016 04:22 PM, John Thornton wrote: 
>> >> Does is have connections to measure the tip voltage? 
>> > I'm not exactly sure, it has a connection named "CNC" and it might 
>>be 
>> > either an input for starting / stopping the cutting or an output 
>>for 
>> > measuring tip voltage. 
>> > 
>> > Best Regards, 
>> > Alexander 
>> > 
>> > 
>> > 
>> > ------------------------------------------------------------ 
>> ------------------ 
>> > 
>> > 
>> > _______________________________________________ 
>> > Emc-users mailing list 
>> > [email protected] 
>> > https://lists.sourceforge.net/lists/listinfo/emc-users 
>> 
>> ------------------------------------------------------------ 
>> ------------------ 
>> What NetFlow Analyzer can do for you? Monitors network bandwidth and 
>> traffic 
>> patterns at an interface-level. Reveals which users, apps, and 
>>protocols 
>> are 
>> consuming the most bandwidth. Provides multi-vendor support for 
>>NetFlow, 
>> J-Flow, sFlow and other flows. Make informed decisions using capacity 
>> planning reports. http://sdm.link/zohodev2dev 
>> _______________________________________________ 
>> Emc-users mailing list 
>> [email protected] 
>> https://lists.sourceforge.net/lists/listinfo/emc-users 
>> 
>------------------------------------------------------------------------------ 
>What NetFlow Analyzer can do for you? Monitors network bandwidth and 
>traffic 
>patterns at an interface-level. Reveals which users, apps, and 
>protocols are 
>consuming the most bandwidth. Provides multi-vendor support for 
>NetFlow, 
>J-Flow, sFlow and other flows. Make informed decisions using capacity 
>planning reports. http://sdm.link/zohodev2dev 
>_______________________________________________ 
>Emc-users mailing list 
>[email protected] 
>https://lists.sourceforge.net/lists/listinfo/emc-users 

------------------------------ 

Message: 4 
Date: Mon, 12 Sep 2016 18:32:14 -0400 
From: Gene Heskett <[email protected]> 
Subject: Re: [Emc-users] output sink of the 667 hall effect? 
To: [email protected] 
Message-ID: <[email protected]> 
Content-Type: Text/Plain; charset="iso-8859-1" 

On Monday 12 September 2016 14:44:33 Chris Albertson wrote: 

> I think the RC filter idea would work OK. Gear teach are after all a 
> low frequency signal, so a filter made with a cap size for a corner 
> freq of (say) 100KHz will keep RF out of the line. 
> 
I was thinking more in terms of a rail to rail bypass. 

> That said the "correct" way to do this is with a pair of 
> driver/receiver chips. If you use RS422 (that is a differential 
> signal) you can likely go over a 1/4 mile of trusted pair wire. 
> 
> As for wire why not use Cat 6 or better for a machine shop cat-6 
> shielded. It is terminated in RJ45 and it's dirt cheap. And has 
> enough pairs (4) for your use. 
> 
> Also I was reading LinuxCNC docs, it said a spindle encoder needs to 
> be quadrature. You need two sensors for that phase A and B plus a 
> third for the index. Cat 6 has four pairs so you can use the 4th 
> for power to the sensors. 

Thats been the plan from the getgo, and its required for rigid tapping. 
Only way to fly IMO. 

> As I said, the simple RC filter like you suggested can work but the 
> "classic" method for use in a shop filled with high power machines is 
> to use a differential single as it is immune to common mode noise, 
> then use twisted pair in a sealed that is grounded on ONE end only, 

I can switch to shielded cable once I get outside the spindle housing, so 
if its needed, I will. 

> On Mon, Sep 12, 2016 at 10:43 AM, Gene Heskett <[email protected]> 
wrote: 
> > Greetings all; 
> > 
> > I see by the spec sheet that the allegro 667 gear sensor can sink up 
> > to 25 mills. 
> > 
> > But with 3 such sensors on the end of a long cable back to the 
> > breakout board, probably 7 foot by the time I get it routed, I am 
> > concerned with the potential for crosstalk noise in spite of putting 
> > a bypass capacitor on the encoder itself. 
> > 
> > This noise would be reduced by a lesser amount of current. So, for 
> > those of you using this device, what value is the resistor are you 
> > using for a pullup at the breakout board? 
> > 
> > And if using a piece of idc ribbon cable, it seems to make sense to 
> > put a grounded wire between each of the A|Z|B conductors, making 
> > that a 7 conductor cable rather than a 5. I have around 90 feet of 
> > 26 wire ribbon I can split off what I need from. 
> > 
> > Good idea? Or off the wall & probably will be plagued by noise if I 
> > shoot for a 10 milliamp pullup with a 470 ohm pullup, or even 5 
> > mills with a 1k pullup. 
> > 
> > Time to assemble that motor driver box I believe. 

Thanks Chris. 
' 
> > 
> > Cheers, Gene Heskett 
> > -- 
> > "There are four boxes to be used in defense of liberty: 
> > soap, ballot, jury, and ammo. Please use in that order." 
> > -Ed Howdershelt (Author) 
> > Genes Web page <http://geneslinuxbox.net:6309/gene> 
> > 
> > -------------------------------------------------------------------- 
> >---------- What NetFlow Analyzer can do for you? Monitors network 
> > bandwidth and traffic patterns at an interface-level. Reveals which 
> > users, apps, and protocols are consuming the most bandwidth. 
> > Provides multi-vendor support for NetFlow, J-Flow, sFlow and other 
> > flows. Make informed decisions using capacity planning reports. 
> > http://sdm.link/zohodev2dev 
> > _______________________________________________ 
> > Emc-users mailing list 
> > [email protected] 
> > https://lists.sourceforge.net/lists/listinfo/emc-users 


Cheers, Gene Heskett 
-- 
"There are four boxes to be used in defense of liberty: 
soap, ballot, jury, and ammo. Please use in that order." 
-Ed Howdershelt (Author) 
Genes Web page <http://geneslinuxbox.net:6309/gene> 



------------------------------ 

Message: 5 
Date: Mon, 12 Sep 2016 19:10:07 -0700 
From: Chris Albertson <[email protected]> 
Subject: Re: [Emc-users] output sink of the 667 hall effect? 
To: "Enhanced Machine Controller (EMC)" 
<[email protected]> 
Message-ID: 
<cabbxvhvxx8ixuigrcljb9wqhudda2dphtbvhpiexn0sq3yq...@mail.gmail.com> 
Content-Type: text/plain; charset=UTF-8 

On Mon, Sep 12, 2016 at 3:32 PM, Gene Heskett <[email protected]> wrote: 
> On Monday 12 September 2016 14:44:33 Chris Albertson wrote: 
> 
>> I think the RC filter idea would work OK. Gear teach are after all a 
>> low frequency signal, so a filter made with a cap size for a corner 
>> freq of (say) 100KHz will keep RF out of the line. 
>> 
> I was thinking more in terms of a rail to rail bypass. 

If the current goes through a series resistor and there is a capacitor 
to ground it is a filter. You can say "bypass" and many people do 
and everyone will know what you mean but the voltage across the cap 
will have frequency content defined by the RC constant of the filter. 
The product of R and C is what matters. You design this likely by 
selecting R based on desired DC characteristics then select C based on 
desired frequency cut off. Just like designing a filter so I call 
them filters 

In larger factory setting people use driver/receiver chips 




-- 

Chris Albertson 
Redondo Beach, California 



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