Post by thread:[PIC] DS1820 wire how long can it go ?

part 1 347 bytes content-type:text/plain; (decoded 7bit) Did anyone have try using DS1820 temp sensor connected with shield wire for more than 50m distance to controller box and without have AC interference ? No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.476 / Virus Database: 269.11.0/927 - Release Date: 7/30/2007 5:02 PM part 2 35 bytes content-type:text/plain; charset="us-ascii" (decoded 7bit)

part 1 326 bytes content-type:text/plain; format=flowed; charset=windows-1250; (decoded 7bit) > Did anyone have try using DS1820 temp sensor connected with shield > wire > for more than 50m distance to controller box and without have AC > interference ? Using twisted pair will give you better noise immunity than a pair of parallel wires. Russell part 2 35 bytes content-type:text/plain; charset="us-ascii" (decoded 7bit)

I am using several DS1820 sensors in networks up to 400m with shielded wires. BUT in the this case the shield is insulated from the data wires. Shield is connected to to the grounded metal housing with EMC cable glands and the electronics is insulated from the housing. I am also using a system where shield and electronics isn't insulated. In these systems we try to maximize cable length to 30m. 50m would be too much I think but it depends on the cable and the driver. I am using a driver with active pull up which helps a lot. Regards / Ruben {Quote hidden}> Did anyone have try using DS1820 temp sensor connected with shield wire > for more than 50m distance to controller box and without have AC > interference ? > > No virus found in this outgoing message. > Checked by AVG Free Edition. > Version: 7.5.476 / Virus Database: 269.11.0/927 - Release Date: > 7/30/2007 5:02 PM > > > > ============================== Ruben Jönsson AB Liros Electronic Box 9124, 200 39 Malmö, Sweden TEL INT +46 40142078 FAX INT +46 40947388 spam_OUTrubenTakeThisOuTpp.sbbs.se ==============================

I've done close to that distance using Cat5 twisted pair....interestingly enough, the device I was measuring the temperature of was a large "in window" air conditioner -- lots of EMI! This setup was parasite powered, for what its worth. -marc On 8/2/07, cllow2020 <.....cllow2020KILLspam@spam@163.com> wrote: {Quote hidden}> Did anyone have try using DS1820 temp sensor connected with shield wire > for more than 50m distance to controller box and without have AC > interference ? > > No virus found in this outgoing message. > Checked by AVG Free Edition. > Version: 7.5.476 / Virus Database: 269.11.0/927 - Release Date: > 7/30/2007 5:02 PM > > > > > -

Thanks Ruben, I'm using shielded wire where shielded net is direct connected to Vcc+5v, inner wire is data signal, it desn't "sound " good enough for pulse data transition. This shield wire are tie-up with some AC shunt motor supply which drain amp. How to add driver on signal line where this signal are bi-direction, I normally use 4k7 pullup only direct to PIC port. {Original Message removed}

Hi, The first article in this PDF describes the circuit I use. <http://www.edn.com/contents/images/3499di.pdf> The article is somewhat unclear about the pullup though. The active pullup is achieved by making the input an output and setting it low in order to make Q2 switch on Q1. This must be done in software just when you have sent a short pulse on the dataline with Q3 either during reading or writing a "1" slot. This means that you need one bidirectional I/O pin and one output only. The circuit is also short circuit proof since it switches off the active pullup if the dataline is pulled low enough. I also use 510 ohms pullup instead of the 4.7k in the circuit. Instead of the D1 in the circuit I have a protection circuit with small resistors, a tvs diode and some shottky diodes to disconnect the capacitance of the tvs diode from the dataline. The oposite end of the data line (where the sensors are) is terminated with a resistor and capacitor. This is also important to get the long wires to work with the low pullup resistor and the active pullup circuit. I use the sensors with parasitic power but I can also use DS2409 lan couplers that is powered with 5V and drive these with the same circuit. We havn't had anyone break yet and we have made thousands. /Ruben > Thanks Ruben, > I'm using shielded wire where shielded net is direct connected to Vcc+5v, inner > wire is data signal, it desn't "sound " good enough for pulse data transition. > This shield wire are tie-up with some AC shunt motor supply which drain amp. How > to add driver on signal line where this signal are bi-direction, I normally use > 4k7 pullup only direct to PIC port. > > > > {Original Message removed}

Marc Nicholas <geekythingKILLspamgmail.com> wrote: > I've done close to that distance using Cat5 twisted > pair....interestingly enough, the device I was measuring the > temperature of was a large "in window" air conditioner -- lots of EMI! I'm curious -- why should there be lots of EMI? AIUI, these units tend to use induction motors exclusively, for both compressor and fan, which are fairly "clean" as far as EMI goes. Modern units probably use SSRs to turn the motors on and off, which would switch on at zero voltage and switch off at zero current, and this should also be fairly clean as far as EMI. -- Dave Tweed

>I'm curious -- why should there be lots of EMI? AIUI, these units >tend to use induction motors exclusively, for both compressor and >fan, which are fairly "clean" as far as EMI goes. I tend to work on the basis that such units have big fat cables, so if they are not generating EMC/EMI themselves, then there is a big conduit bringing such interference from somewhere that does generate it, and radiate where it is not wanted.

part 1 1399 bytes content-type:text/plain; (decoded 7bit) I intend to use DS1820 at an environment for mountain plantation area( not green house, is open area). Where there are auto control of temp for water cooling, lighting control at night-time and chemical water spray. Challenge is the tempreture sensor have to tie-up with 60A AC power cables which provide 5 units of motor each 5 hp and some lights. The best way is to split into 5's location area with 5 individual controller box, each controller handle ~ diameter of 60m area. But sadly to said is 5 times costly. this project is at green tea plantation and flower plantation at mountain area. Thanks for all info. Best regards cllow2020 {Original Message removed}

On 8/3/07, cllow2020 <.....cllow2020KILLspam.....163.com> wrote: > I intend to use DS1820 at an environment for mountain plantation area( > not green house, is open area). Where there are auto control of temp for > water cooling, lighting control at night-time and chemical water spray. > Challenge is the tempreture sensor have to tie-up with 60A AC power > cables which provide 5 units of motor each 5 hp and some lights. If "tie-up" means for you using the same cable for AC and sensor, it's about a wrong design and not a challenge. If it's something else please excuse my poor english. The DS18B20 is working without any active pullup in a 50m chain using CAT5 cable where data is twisted with GND in one pair and VCC is twisted with GND in the second pair.The twisted pair has lower capacitance than shielded cable, and is much better. Vasile

there is some difference between DS18B20 & DS1820, as far as I tried DS18B20, with 30M have to pullup till 470 ohm even with cat5. software...impact, well "tie-up" means cable-tie up , no metal contact, along with 415V@60A 3phase power cables 50m away. -------------------------------------------------- From: "Vasile Surducan" <EraseMEpiclist9spam_OUTTakeThisOuTgmail.com> Sent: Monday, June 09, 2008 11:18 PM To: "Microcontroller discussion list - Public." <piclistspam_OUTmit.edu> Subject: Re: [PIC] DS1820 wire how long can it go ? {Quote hidden}> On 8/3/07, cllow2020 <@spam@cllow2020KILLspam163.com> wrote: >> I intend to use DS1820 at an environment for mountain plantation area( >> not green house, is open area). Where there are auto control of temp for >> water cooling, lighting control at night-time and chemical water spray. > > >> Challenge is the tempreture sensor have to tie-up with 60A AC power >> cables which provide 5 units of motor each 5 hp and some lights. > > If "tie-up" means for you using the same cable for AC and sensor, it's > about a wrong design and not a challenge. If it's something else > please excuse my poor english. The DS18B20 is working without any > active pullup in a 50m chain using CAT5 cable where data is twisted > with GND in one pair and VCC is twisted with GND in the second > pair.The twisted pair has lower capacitance than shielded cable, and > is much better. > > Vasile > --

On 6/10/08, cllow2020(gmail) <KILLspamcllow2020KILLspamgmail.com> wrote: > there is some difference between DS18B20 & DS1820, as far as I tried > DS18B20, with 30M have to pullup till 470 ohm even with cat5. > software...impact, well > > "tie-up" means cable-tie up , no metal contact, along with 415V@60A 3phase > power cables 50m away. > AFIK here is forbidden to carry a signal and a power cable one near the other, but if this is the requirement, forgot about 1 wire bus and use a serious RS485. greetings, Wesley (Vasile) {Quote hidden}> > -------------------------------------------------- > From: "Vasile Surducan" <RemoveMEpiclist9TakeThisOuTgmail.com> > Sent: Monday, June 09, 2008 11:18 PM > To: "Microcontroller discussion list - Public." <spamBeGonepiclistspamBeGonemit.edu> > Subject: Re: [PIC] DS1820 wire how long can it go ? > > > On 8/3/07, cllow2020 <TakeThisOuTcllow2020EraseMEspam_OUT163.com> wrote: > >> I intend to use DS1820 at an environment for mountain plantation area( > >> not green house, is open area). Where there are auto control of temp for > >> water cooling, lighting control at night-time and chemical water spray. > > > > > >> Challenge is the tempreture sensor have to tie-up with 60A AC power > >> cables which provide 5 units of motor each 5 hp and some lights. > > > > If "tie-up" means for you using the same cable for AC and sensor, it's > > about a wrong design and not a challenge. If it's something else > > please excuse my poor english. The DS18B20 is working without any > > active pullup in a 50m chain using CAT5 cable where data is twisted > > with GND in one pair and VCC is twisted with GND in the second > > pair.The twisted pair has lower capacitance than shielded cable, and > > is much better. > > > > Vasile > > --