Re: [Owfs-developers] how many 18b20s on a bus

- Nearly "no power" required - some years of tests/experience with thousands of sensors - one wire less means 1/3 less could fail, no sep. power-supply means another part that cannot fail. As said, beat me, I know this opinion isn't shared by all.. Michael On 04.10.2014 00:29, Colin Reese wrote:

Re: [Owfs-developers] how many 18b20s on a bus

Parasitic is less error-prone? Why is this? Colin On Fri, Oct 3, 2014 at 2:55 PM, Michael Markstaller wrote: > If you can live with some time to read them, lets say 180-300 secs.: > Parasitic 50-100 on a cheap DS9490 are working like a charm without any > needs for other big expenses; > If the

Re: [Owfs-developers] how many 18b20s on a bus

If you can live with some time to read them, lets say 180-300 secs.: Parasitic 50-100 on a cheap DS9490 are working like a charm without any needs for other big expenses; If the lines are short (read: below ~300ft) more might be possible. The "keyword" is parasitic! It's much easier, much less erro

Re: [Owfs-developers] how many 18b20s on a bus

I use 18B20's on my solar panels. There have been a couple of occasions when the pump has failed and the panels and sensors have reached 127C and 3 of the 4 still work OK, the 4th works most of the time, don't know if it was the high temp that caused the problem with that, it certainly didn't

Re: [Owfs-developers] how many 18b20s on a bus

Maybe you should use eletronic devices to control it, i'm talking about small devices like microcontroller or even thermorelay i don't kmow the control loop but temperature is easily controles with on/off control, but if you need a fine control maybe any small controller solve it I don't know your

Re: [Owfs-developers] how many 18b20s on a bus

Nothing nearly that exciting. Hundreds of laptop power bricks. On 10/01/2014 11:05 PM, Roberto Spadim wrote: Well its a radio station? Or a sound amp? Em quinta-feira, 2 de outubro de 2014, Jerry Scharf > escreveu: Hi, Thanks for all the input.

Re: [Owfs-developers] how many 18b20s on a bus

Well its a radio station? Or a sound amp? Em quinta-feira, 2 de outubro de 2014, Jerry Scharf < sch...@lagunawayconsulting.com> escreveu: > Hi, > > Thanks for all the input. I am guessing my experience with slow reads is > due to the long buses I have with my current setup. > > The bus will be ve

Re: [Owfs-developers] how many 18b20s on a bus

Hi, Thanks for all the input. I am guessing my experience with slow reads is due to the long buses I have with my current setup. The bus will be very short because all the load resistors are on a rack with water cooled heat sinks. I can make the main power and ground lines any gauge I want, an

Re: [Owfs-developers] how many 18b20s on a bus

if it's not to control a process, i think could use without problems, like paul told, temperature don't change too fast, only if you are controlling something, in this case should check system update rate using modbus devices i got ~20ms to read 8 termocouples with rs485 (serial) 9600bauds i think

Re: [Owfs-developers] how many 18b20s on a bus

I've done over 100 DS18S20's (passive) on passive, active, Link and DS9490 successfully. It isn't fast, but then your temperature changes aren't that fast. On Wed, Oct 1, 2014 at 4:53 PM, Roberto Spadim wrote: > that what i stored here some years ago when testing ds1820 devices > in other words

Re: [Owfs-developers] how many 18b20s on a bus

that what i stored here some years ago when testing ds1820 devices in other words 300*.01 = 3 seconds maybe less maybe more what update period you need? -- Meet PCI DSS 3.0 Compliance Requirements with EventLog Analyzer A

Re: [Owfs-developers] how many 18b20s on a bus

That sounds about right to me. On Wed, Oct 1, 2014 at 1:44 PM, Roberto Spadim wrote: > check if i'm wrong, <10ms per scratchpad > > 2014-10-01 16:38 GMT-03:00 Colin Reese : > > Read scratchpad is pretty darn fast. I'd have to go back to my notes to > see > > exactly how fast. If I remember corre

Re: [Owfs-developers] how many 18b20s on a bus

Am 01.10.2014 um 20:57 schrieb Jerry Scharf: > > I was planning on a large power supply and using simultaneous mode, but > I know, this is my pet passion, but having done a number of larger networks with central powering delivered through the bus cable, I strongly advise you to have a thick GND l

Re: [Owfs-developers] how many 18b20s on a bus

check if i'm wrong, <10ms per scratchpad 2014-10-01 16:38 GMT-03:00 Colin Reese : > Read scratchpad is pretty darn fast. I'd have to go back to my notes to see > exactly how fast. If I remember correctly, the convert will take something > like 1mA per device during conversion. > > You can also tak

Re: [Owfs-developers] how many 18b20s on a bus

Read scratchpad is pretty darn fast. I'd have to go back to my notes to see exactly how fast. If I remember correctly, the convert will take something like 1mA per device during conversion. You can also take turns with bunches of devices, reading a smaller subset so as to optimize load on the bus.

Re: [Owfs-developers] how many 18b20s on a bus

:) probably yes but any problem including more buses devices? 2014-10-01 15:57 GMT-03:00 Jerry Scharf : > Roberto, > > I was planning on a large power supply and using simultaneous mode, but > from my prior experience we still wouldn't be able to poll the > temperature of all the devices very quic

Re: [Owfs-developers] how many 18b20s on a bus

here using usb-serial isnt a problem but if i remember some linux usb-serial drivers have a limit of howmany devices/computer could be used maybe it' near to 16usd/computer (per linux operational system) 2014-10-01 16:13 GMT-03:00 Roberto Spadim : > :) probably yes > but any problem including more

Re: [Owfs-developers] how many 18b20s on a bus

Roberto, I was planning on a large power supply and using simultaneous mode, but from my prior experience we still wouldn't be able to poll the temperature of all the devices very quickly. Thus the need for more buses to run in parallel. jerry On 10/01/2014 11:53 AM, Roberto Spadim wrote: > h

Re: [Owfs-developers] how many 18b20s on a bus

hummm you need to measure, or check a alarm condition? with 300 using alarm condition is possible only alarmmed sensors will be reported at bus, it's not temperature convertion it's only alarm information (alarm on/off) measuring temperature you should use (i don't remember the owfs file name) a

[Owfs-developers] how many 18b20s on a bus

Hi, I am looking at using 18b20s to measure some load resistors and a couple other things. This is for a large bank of unit under test. The thing is that there are 300 load resistors plus 20-30 other channels to track. Then again, if we do a second monitor point, that's another 300 sensors. >F