Galvanische Trennung ?!

[Stefan]

Hallo Kollegen,

Ich hab ein kleines Problem mit einer galvanischen Trennung. Ich
möchte ein Druckregelventil mit einer PC-Messkarte (NI6071
E-Serie)steuern, die mir eine analoge Spannung zwischen 0 und 10 Volt
erzeugen kann.
Nun habe ich Bedenken dass das Druckregelventil mir eventuell die
Messkarte zerschiesst (hat ne Spule drin). Die Theorie wird leider
durch die Tatsache untermauert, dass in dem Ventil keine galvanische
Trennung realisiert wurde (lt. Hersteller Auskunft).
Ich weiß nicht so genau, ich denke dass sich die Regelelektronik im
Ventil nicht lange halten würde wenn die sich nicht um den
Energierückfluss durch die Magnetspule kümmern würde und es eigentlich
kein Probelm geben sollte wenn ich das Ventil einfach an die Karte
hänge - aber ich bin mir eben nicht sicher.

Die Eingangsimpedanz des Spannungseingangs des Ventil liegt bei 10 K.
Der Analogausgang der Messkarte hat 0.1 Ohm Impedanz.

Jetzt die Frage :

Wie kann ich eine galvansiche Trennung relaisieren, bei der die
Ausgangsspannung variierbar ist. D.h. ich will ja nicht nur 2
Stromkreise trennen, sondern immer proportional bleiben.
Zuerst dachte ich an Optokoppler, aber die Dinger kennen ja nur 2
Zustände und ich kann da ja wieder nicht stufenlos variieren.
Dann hatte mit dem Gedanken gespielt einen DC/DC Wandler dafür zu
nutzen, aber die Ausgangsspannungen der Dinger sind ja nicht
veränderbar.

Weiß jemand was es für Möglichkeiten der galvanischen Trennung gibt
bei denen die Ausgangsgröße (U) variierbar ist ? Die Lösung sollte
möglichst billig bleiben. Ich darf nicht viel Geld dafür ausgeben -
also wenn möglich einfach Vorschläge im LowCost Bereich (bis ca 50
EUR).

Ich wäre um ein paar Inputs froh.


Gruß,

Stefan

 

[Rich Grise]

On Mon, 15 Nov 2004 11:03:39 +0100, Rene Tschaggelar wrote:

Stefan wrote:

Hallo Kollegen,

Ich hab ein kleines Problem mit einer galvanischen Trennung. Ich
möchte ein Druckregelventil mit einer PC-Messkarte (NI6071
E-Serie)steuern, die mir eine analoge Spannung zwischen 0 und 10 Volt
erzeugen kann.
Nun habe ich Bedenken dass das Druckregelventil mir eventuell die
Messkarte zerschiesst (hat ne Spule drin). Die Theorie wird leider
durch die Tatsache untermauert, dass in dem Ventil keine galvanische
Trennung realisiert wurde (lt. Hersteller Auskunft).
Ich weiß nicht so genau, ich denke dass sich die Regelelektronik im
Ventil nicht lange halten würde wenn die sich nicht um den
Energierückfluss durch die Magnetspule kümmern würde und es eigentlich
kein Probelm geben sollte wenn ich das Ventil einfach an die Karte
hänge - aber ich bin mir eben nicht sicher.

Die Eingangsimpedanz des Spannungseingangs des Ventil liegt bei 10 K.
Der Analogausgang der Messkarte hat 0.1 Ohm Impedanz.

Jetzt die Frage :

Wie kann ich eine galvansiche Trennung relaisieren, bei der die
Ausgangsspannung variierbar ist. D.h. ich will ja nicht nur 2
Stromkreise trennen, sondern immer proportional bleiben.
Zuerst dachte ich an Optokoppler, aber die Dinger kennen ja nur 2
Zustände und ich kann da ja wieder nicht stufenlos variieren.
Dann hatte mit dem Gedanken gespielt einen DC/DC Wandler dafür zu
nutzen, aber die Ausgangsspannungen der Dinger sind ja nicht
veränderbar.

Weiß jemand was es für Möglichkeiten der galvanischen Trennung gibt
bei denen die Ausgangsgröße (U) variierbar ist ? Die Lösung sollte
möglichst billig bleiben. Ich darf nicht viel Geld dafür ausgeben -
also wenn möglich einfach Vorschläge im LowCost Bereich (bis ca 50
EUR).

Ich wäre um ein paar Inputs froh.

Stefan,
Die 0 bis 10V lassen nicht auf eine induktive last schliessen.
Daher : direkt anhaengen. Eine Z-diode von 10V oder so
sollte genuegen.

That's easy for _you_ to say!

;-)
Rich

 

[Jonathan Kirwan]

On Mon, 15 Nov 2004 19:40:23 GMT, Rich Grise <rich@example.net> wrote:

That's easy for _you_ to say!

You should learn to read German -- seems like 50% of it is in English, already.

Ich I
hab have
ein a
kleines small
Problem problem
...
etc.

I just don't know if the zener is the solution here.

Jon

 

[Joerg]

Hi Jonathan,

You should learn to read German -- seems like 50% of it is in English, already.

Ich I
hab have
ein a
kleines small
Problem problem
...
etc.

I believe neither the Germans nor the English can claim the word
'problem'. The Romans hold the patent or maybe the ancient Greeks. But I
guess patents expire after 20 years.

I just don't know if the zener is the solution here.

Stefan should be able to obtain enough details about the valve from the
manufacturer. If the manufacturer can't furnish that I would not use
this controlled valve at all. Seem like they all need to be controlled
by something so this must be "the" typical application.


Totally OT: I just joined the Yahoo MSP430 group and saw your name in
some posts. How do you configure that screen so it shows threads as
nicely as a newsreader? I could only see 'date' and 'thread' settings,
both of which do not produce any decent user interface but just pages
after pages you have to flip through.

Regards, Joerg

http://www.analogconsultants.com

 

[Jonathan Kirwan]

On Mon, 15 Nov 2004 20:41:01 GMT, Joerg <notthisjoergsch@removethispacbell.net>
wrote:

Hi Jonathan,

You should learn to read German -- seems like 50% of it is in English, already.

Ich I
hab have
ein a
kleines small
Problem problem
...
etc.



I believe neither the Germans nor the English can claim the word
'problem'. The Romans hold the patent or maybe the ancient Greeks. But I
guess patents expire after 20 years.

hehe. I wasn't indicating ownership, just ease of reading. Although I can't
produce German well, I can read it fluently. Just a little practice is all it
takes. The words start picking right up and the verb order gets "normal" soon
enough. Conjugation isn't hard, either, from a reader's perspective. I now
often read Deutsche Welle, "auf Deutch."

I just don't know if the zener is the solution here.


Stefan should be able to obtain enough details about the valve from the
manufacturer. If the manufacturer can't furnish that I would not use
this controlled valve at all. Seem like they all need to be controlled
by something so this must be "the" typical application.

Yup.

Totally OT: I just joined the Yahoo MSP430 group and saw your name in
some posts. How do you configure that screen so it shows threads as
nicely as a newsreader? I could only see 'date' and 'thread' settings,
both of which do not produce any decent user interface but just pages
after pages you have to flip through.

I don't use the web browser, at all. Yuk.

What I do is simply set up my account there for sending all the posts as email
to my email account. I then set up Agent to filter on the subject and
automatically toss these into a special folder just for this group. Agent
automatically threads and date sorts them for me. Works just like reading a
newsgroup, that way.

Jon

 

[Jonathan Kirwan]

On Mon, 15 Nov 2004 22:31:16 GMT, Joerg <notthisjoergsch@removethispacbell.net>
wrote:

Hi Jonathan,

hehe. I wasn't indicating ownership, just ease of reading. Although I can't
produce German well, I can read it fluently. Just a little practice is all it
takes. The words start picking right up and the verb order gets "normal" soon
enough. Conjugation isn't hard, either, from a reader's perspective. I now
often read Deutsche Welle, "auf Deutch."


That is a great way to learn a language. You can also listen to DW on
the web but I still prefer the shortwave receiver.

I do listen to DW via shortwave, though the speech is sometimes too fast for me
to follow. Also, I listened to the world broadcasts from Moscow and a variety
of other places where English is available. The news services here are so much
the controlled *sameness* as each other that the only way to have even a slight
chance at getting some balance is to listen to many different slants and then
forge an amalgam of your own that provides that balanced, comprehensive
viewpoint.

(It's really pretty sad, though, for US news sources, which you'd well imagine
could provide substantial variety and a great deal of depth for all the time and
money they soak up. But you can turn to different broadcast news programs in
the US and get almost exactly the same story with exactly the same slant at
exactly the same clock time. No variation -- might as well have only one
service. This is particularly put into context when you listen to shortwave.)

Sometimes I listen to
Spanish radio on AM, which could be as much as a third of the stations
out here in California. The problem is that their 'bit rate' is at least
twice as high as ours. That goes even higher when they comment a soccer
game.

hehe. I've learned almost no Spanish, though. I suppose I should try.

I don't use the web browser, at all. Yuk.

What I do is simply set up my account there for sending all the posts as email
to my email account. I then set up Agent to filter on the subject and
automatically toss these into a special folder just for this group. Agent
automatically threads and date sorts them for me. Works just like reading a
newsgroup, that way.


I thought about that but then I didn't want a flood of stuff going
through my email account. Also, it makes the whole process so
non-realtime. I wish they were allowing newsreader access just like
Cadsoft does with their support forums. Or maybe TI should have rather
done that directly. I find that this page flipping on the web interface
for the MSP group is terrible. I have no idea why companies like
National or TI didn't embrace the well established Usenet protocol.

It's not a "flood," so don't worry about that. Yeah, NNTP would be nice. But I
think there is something going on here about allowing these groups to be private
and variously controlled by their moderators, so perhaps NNTP fails on this
score.

Jon

 

[Joerg]

Hi Jonathan,

I do listen to DW via shortwave, though the speech is sometimes too fast for me
to follow. Also, I listened to the world broadcasts from Moscow and a variety
of other places where English is available. The news services here are so much
the controlled *sameness* as each other that the only way to have even a slight
chance at getting some balance is to listen to many different slants and then
forge an amalgam of your own that provides that balanced, comprehensive
viewpoint.

(It's really pretty sad, though, for US news sources, which you'd well imagine
could provide substantial variety and a great deal of depth for all the time and
money they soak up. But you can turn to different broadcast news programs in
the US and get almost exactly the same story with exactly the same slant at
exactly the same clock time. No variation -- might as well have only one
service. This is particularly put into context when you listen to shortwave.)

Yes, its pretty bland. My main gripe is that there is no depth of
information to speak of, except maybe the PBS news but those are also
not always so non-partisan in my view. I like the BBC World Service.
Moscow? Nah, at least that used to be all propaganda which I couldn't
stand. I did enjoy the concerts from there though, especially the large
choirs they have.

It's not a "flood," so don't worry about that. Yeah, NNTP would be nice. But I
think there is something going on here about allowing these groups to be private
and variously controlled by their moderators, so perhaps NNTP fails on this
score.

I am not an expert at all on NNTP but, for example, the Cadsoft groups
are not available through regular subscription via my ISP. They are
hosted on the company server and are moderated from there. They don't
censor it as far as I can see but a few of their engineers participate
and answer questions which is really nice. But the best is that it can
be accessed through a regular newsreader. It only shows up under a
separate news server name.

Regards, Joerg

http://www.analogconsultants.com

 

[Rene Tschaggelar]

Rich Grise wrote:

On Mon, 15 Nov 2004 11:03:39 +0100, Rene Tschaggelar wrote:


Stefan wrote:
[snip]
Ich wäre um ein paar Inputs froh.

Stefan,
Die 0 bis 10V lassen nicht auf eine induktive last schliessen.
Daher : direkt anhaengen. Eine Z-diode von 10V oder so
sollte genuegen.



That's easy for _you_ to say!

True, indeed.
If the input is 10k linear with voltage then there is a driver
involved. Or how do you set a linear(!) valve with that little
current ?

Rene
--
Ing.Buero R.Tschaggelar - http://www.ibrtses.com
& commercial newsgroups - http://www.talkto.net

 

[Rene Tschaggelar]

Joerg wrote:

Hi Rene,

The usenet protocol and also the most common news servers would allow
moderation. It is a matter of screening the incoming messages
before they are put into the server for download.
Also having a closed user group, eg with passwords is doable.
Just in case someone requires an NNTP newsgroup of his own :
http://www.talkto.net - that's me, BTW.


Interesting. On your web site you say that all NGs are public. Is that
really so? For example, if Cadsoft wanted the access limited to clients
only, couldn't they just refuse a connection to their server for anyone
not on the list of approved clients?

As to my newsgroups :
They are accessible from the public. However there are some that
only appear after supplying a username/password. Without
username/password they don't even appear on the list of newsgroups.
The current version of thunderbird is not able to get a list of the
newsgroups AFTER a username/password as far as I know. Then another
newsclient is recommended.

So, yes, selective access is doable.

Rene
--
Ing.Buero R.Tschaggelar - http://www.ibrtses.com
& commercial newsgroups - http://www.talkto.net

 

[Rene Tschaggelar]

Stefan wrote:

Hallo Kollegen,

Ich hab ein kleines Problem mit einer galvanischen Trennung. Ich
möchte ein Druckregelventil mit einer PC-Messkarte (NI6071
E-Serie)steuern, die mir eine analoge Spannung zwischen 0 und 10 Volt
erzeugen kann.
Nun habe ich Bedenken dass das Druckregelventil mir eventuell die
Messkarte zerschiesst (hat ne Spule drin). Die Theorie wird leider
durch die Tatsache untermauert, dass in dem Ventil keine galvanische
Trennung realisiert wurde (lt. Hersteller Auskunft).
Ich weiß nicht so genau, ich denke dass sich die Regelelektronik im
Ventil nicht lange halten würde wenn die sich nicht um den
Energierückfluss durch die Magnetspule kümmern würde und es eigentlich
kein Probelm geben sollte wenn ich das Ventil einfach an die Karte
hänge - aber ich bin mir eben nicht sicher.

Die Eingangsimpedanz des Spannungseingangs des Ventil liegt bei 10 K.
Der Analogausgang der Messkarte hat 0.1 Ohm Impedanz.

Jetzt die Frage :

Wie kann ich eine galvansiche Trennung relaisieren, bei der die
Ausgangsspannung variierbar ist. D.h. ich will ja nicht nur 2
Stromkreise trennen, sondern immer proportional bleiben.
Zuerst dachte ich an Optokoppler, aber die Dinger kennen ja nur 2
Zustände und ich kann da ja wieder nicht stufenlos variieren.
Dann hatte mit dem Gedanken gespielt einen DC/DC Wandler dafür zu
nutzen, aber die Ausgangsspannungen der Dinger sind ja nicht
veränderbar.

Weiß jemand was es für Möglichkeiten der galvanischen Trennung gibt
bei denen die Ausgangsgröße (U) variierbar ist ? Die Lösung sollte
möglichst billig bleiben. Ich darf nicht viel Geld dafür ausgeben -
also wenn möglich einfach Vorschläge im LowCost Bereich (bis ca 50
EUR).

Ich wäre um ein paar Inputs froh.

Stefan,
Die 0 bis 10V lassen nicht auf eine induktive last schliessen.
Daher : direkt anhaengen. Eine Z-diode von 10V oder so
sollte genuegen.

Rene
--
Ing.Buero R.Tschaggelar - http://www.ibrtses.com
& commercial newsgroups - http://www.talkto.net

 

[Rene Tschaggelar]

Jonathan Kirwan wrote:

On Mon, 15 Nov 2004 22:31:16 GMT, Joerg <notthisjoergsch@removethispacbell.net
wrote:
[snip]

I thought about that but then I didn't want a flood of stuff going
through my email account. Also, it makes the whole process so
non-realtime. I wish they were allowing newsreader access just like
Cadsoft does with their support forums. Or maybe TI should have rather
done that directly. I find that this page flipping on the web interface
for the MSP group is terrible. I have no idea why companies like
National or TI didn't embrace the well established Usenet protocol.


It's not a "flood," so don't worry about that. Yeah, NNTP would be nice. But I
think there is something going on here about allowing these groups to be private
and variously controlled by their moderators, so perhaps NNTP fails on this
score.

The usenet protocol and also the most common news servers would allow
moderation. It is a matter of screening the incoming messages
before they are put into the server for download.
Also having a closed user group, eg with passwords is doable.
Just in case someone requires an NNTP newsgroup of his own :
http://www.talkto.net - that's me, BTW.

Rene
--
Ing.Buero R.Tschaggelar - http://www.ibrtses.com
& commercial newsgroups - http://www.talkto.net

 

[Joerg]

Hi Jonathan,

hehe. I wasn't indicating ownership, just ease of reading. Although I can't
produce German well, I can read it fluently. Just a little practice is all it
takes. The words start picking right up and the verb order gets "normal" soon
enough. Conjugation isn't hard, either, from a reader's perspective. I now
often read Deutsche Welle, "auf Deutch."

That is a great way to learn a language. You can also listen to DW on
the web but I still prefer the shortwave receiver. Sometimes I listen to
Spanish radio on AM, which could be as much as a third of the stations
out here in California. The problem is that their 'bit rate' is at least
twice as high as ours. That goes even higher when they comment a soccer
game.

Totally OT: I just joined the Yahoo MSP430 group and saw your name in
some posts. How do you configure that screen so it shows threads as
nicely as a newsreader? I could only see 'date' and 'thread' settings,
both of which do not produce any decent user interface but just pages
after pages you have to flip through.



I don't use the web browser, at all. Yuk.

What I do is simply set up my account there for sending all the posts as email
to my email account. I then set up Agent to filter on the subject and
automatically toss these into a special folder just for this group. Agent
automatically threads and date sorts them for me. Works just like reading a
newsgroup, that way.

I thought about that but then I didn't want a flood of stuff going
through my email account. Also, it makes the whole process so
non-realtime. I wish they were allowing newsreader access just like
Cadsoft does with their support forums. Or maybe TI should have rather
done that directly. I find that this page flipping on the web interface
for the MSP group is terrible. I have no idea why companies like
National or TI didn't embrace the well established Usenet protocol.

Regards, Joerg

http://www.analogconsultants.com

 

[Joerg]

Hi Rene,

The usenet protocol and also the most common news servers would allow
moderation. It is a matter of screening the incoming messages
before they are put into the server for download.
Also having a closed user group, eg with passwords is doable.
Just in case someone requires an NNTP newsgroup of his own :
http://www.talkto.net - that's me, BTW.

Interesting. On your web site you say that all NGs are public. Is that
really so? For example, if Cadsoft wanted the access limited to clients
only, couldn't they just refuse a connection to their server for anyone
not on the list of approved clients?

Regards, Joerg

http://www.analogconsultants.com