RE: Single ended termination

Hello Andreas,

sincere thanks for providing, hosting and managing the list over the years.

Regrettably I have to agree, it's becoming silent in the CAN world.
My company started the first CAN device (an DSP-402-drive) back in the late=
 nineties.
We had many CAN products since then and even some very special setups (i.e.=
 CAN over plastic fiber in an magnetic resonance medical device).
But focus shifted, nowadays we do most of our new stuff for ethernet varian=
ts like Profinet or Ethercat.
Yes, we still sell CAN stuff, but no new developed devices.

It was always fun following the list, i.e. Johns articles about the Olympic=
 rings were absolute highlights.
The list was very informative, educative and always a good place to ask spe=
cial questions.

But times are changing, for me it's now still fun reading here but not long=
er something I need for work.
So from my side it's absolutely ok to turn off the list if it's getting dif=
ficult running it in a secure way.

Thanks again
  Matthias

> Neubauer, Andreas <[email protected]> hat am 12.02.2021 16:46 g=
eschrieben:
>=20
> =20
> Hi John,
> the list has a long history indeed, and the experienced contributors like=
 you are what makes it worthwhile in the first place. I always really enjoy=
ed managing the list, but I notice that the community has become smaller an=
d smaller over the years (585 subscribers currently, 95% of them have been =
silent for years). We had less than 20 threads last year, so I wonder if it=
 still makes sense to keep the list up and running to be honest. The majord=
omo software it runs on must be shut down soon because it has long been out=
dated (no updates available). It=E2=80=99s possible to migrate to a hosted =
list service, but is it worth the effort? It might be more rational to cons=
ider closing the list. What do you think?
>=20
> Andreas
> CANLIST Administration
>=20
>=20
> From: [email protected] <canlist-owner@vector-informati=
k.com> On Behalf Of John Dammeyer
> Sent: Thursday, February 11, 2021 10:06 AM
> To: 'CAN Mailinglist' <[email protected]>
> Subject: RE: [CANLIST] Single ended termination
>=20
> Works like a charm.  Thanks for that.
>=20
> I was just privately commenting to Heikki about the history of this CAN l=
ist and how it spawned from comp.arch.embedded  (1997) and from there Ken T=
indell formed the original group.  When Ken left Univeristy of Upsalla  Vec=
tor kindly took it over without any advertising or prejudice.  So impressiv=
e in this day and age.
>=20
> So thanks again and to you and Vector for supporting a non-partisan open =
forum.
>=20
> John Dammeyer
>=20
>=20
> From: [email protected]<mailto:canlist-owner@vector-inf=
ormatik.com> [mailto:[email protected]] On Behalf Of Neub=
auer, Andreas
> Sent: February-11-21 12:53 AM
> To: CAN Mailinglist ([email protected]<mailto:[email protected]>)
> Subject: RE: [CANLIST] Single ended termination
>=20
> Hi,
> please go to https://canlist.org/ directly if you do not get redirected t=
here from http://www.canlist.org/.<http://www.canlist.org/> The SSL certifi=
cate doesn=E2=80=99t cover the variant with =E2=80=9Cwww=E2=80=9D and I had=
 missed to redirect this automatically. This is fixed now, but some browser=
s might have cached the previous redirect.
>=20
> Andreas
> CANLIST Administration
>=20
>=20
> From: [email protected]<mailto:canlist-owner@vector-inf=
ormatik.com> <[email protected]<mailto:canlist-owner@vect=
or-informatik.com>> On Behalf Of John Dammeyer
> Sent: Thursday, February 11, 2021 9:23 AM
> To: [email protected]<mailto:[email protected]>
> Subject: RE: [CANLIST] Single ended termination
>=20
> Heikki,
> Your message did come through as did a number of others a day after I fir=
st posted mine.
>=20
> I've also noticed and reported that the www.canlist.org<http://www.canlis=
t.org>  site is considered dangerous by several browsers.  Something about =
a security certificate.
>=20
> Back around 2011, TI's Steve Corrigan had retired and he and I had starte=
d looking into cable behaviour on CAN messages.  I'd sent him some surplus =
Thick DeviceNet cable for some experiments.  However he unfortunately passe=
d before we had much of a chance to do anything with that.  Never really go=
t back to it.  He really was the expert on this bus.
>=20
> Since then most of my CAN systems have had no more than about 10 nodes an=
d there are some rules broken.  Mostly on stub lengths.  It's a difficult b=
attle with mechanical engineers who don't understand that 50 ohm cable is d=
ifferent from 120 ohm cable.  Especially when the thin 50 ohm fits so well =
and bends so easily.
>=20
> This summer or fall I hope to get back into some really long CAN bus netw=
orks at slower bus rates.  Maybe 100kbps for garden lighting and security. =
 Such as system may not use 120 ohm cable for everything just to do some te=
sting.
>=20
> John Dammeyer
>=20
>=20
>=20
> From: [email protected]<mailto:canlist-owner@vector-inf=
ormatik.com> [mailto:[email protected]] On Behalf Of Heik=
ki Saha
> Sent: February-11-21 12:08 AM
> To: [email protected]<mailto:[email protected]>
> Subject: [CANLIST] Single ended termination
>=20
> Hello,
>=20
> Had problems getting this through, John already provided nice scope scree=
nshot as an example.
>=20
> The purpose of the terminator is to get the end of the transmission line =
look like an infinitely long line with impedance equal to the line impedanc=
e (120ohm with CAN) and thus prevent reflections. Thus, single terminator m=
ay be installed into one end, but the another end remains unterminated (inf=
inite impedance), which leads into over- and undershoots. While the communi=
cation will pass through, the transmission line is still broken. From pract=
ical point of view, the most significant risk is that any other problem mor=
e will lead into total black-out. And one shall keep in mind that the physi=
cal layer design has a direct effect on the bit error probability, which is=
 a basis for residual error rate, which has further effect on the availabil=
ity and safety performance of the entire system -- it is easy to violate th=
e system requirements with a poor CAN cabling design.
>=20
> There are some reference designs (published by Daimler) in the literature=
 for centre termination but they cannot be recommended, because each of suc=
h networks needs to be intentionally fine tuned. In addition to the clumsy =
design, such will be a service nightmare.
>=20
> My recommendation is to adopt a standard cabling and connector scheme, wh=
ere you'll find batch cables, Y- or V-branches and termination plugs, e.g. =
MiniChange, M12 or Deutsch DT04/06 series.
>=20
> Best regards,
>=20
> Heikki Saha, CTO
>   M.Sc. Automation
>   Dr.Tech. Electronics
> TK Engineering Oy
> Hovioikeudenpuistikko 13 as 3, 65100 Vaasa
> +358 (0)50 588 6894
> email: [email protected]<mailto:[email protected]>
> skype: heikki.saha_tke
>=20
> We are also in the 17th iCC: https://www.can-cia.org/icc

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