1-wire Device - Distance Question
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Posts: 46,084
I am attempting to connect a Maxim DS18B20 1-wire temperature sensor to my
BS2P24. Using me BS2p Demo Board I don't have a problem communication with
the sensor. Then I placed a sensor at the ends of separate 25ft and 50ft
runs of CAT5 Twisted Pair computer network wire. 3 wires were all that were
needed. +5v, GND, and the 1-wire communication line. I cannot get a
response. I measured the wire and there is very little resistance and the
connections appear correct. If I plug the sensor to the Demo board and
attach my extension without a device on the end, I get the same result as
with the device connected to the end of the cable. What am I missing?
PS. of interesting note, I used the code from the Basic Stamp Manual to
retrieve the devices serial number. It runs fine with the device connected
locally. When the sensor is remote it doesn't error out due to no 1-wire
device detected, nor does it return the address. If I remove the device from
the cable, it errors out.
Thank you,
Phillip Kocmoud
BS2P24. Using me BS2p Demo Board I don't have a problem communication with
the sensor. Then I placed a sensor at the ends of separate 25ft and 50ft
runs of CAT5 Twisted Pair computer network wire. 3 wires were all that were
needed. +5v, GND, and the 1-wire communication line. I cannot get a
response. I measured the wire and there is very little resistance and the
connections appear correct. If I plug the sensor to the Demo board and
attach my extension without a device on the end, I get the same result as
with the device connected to the end of the cable. What am I missing?
PS. of interesting note, I used the code from the Basic Stamp Manual to
retrieve the devices serial number. It runs fine with the device connected
locally. When the sensor is remote it doesn't error out due to no 1-wire
device detected, nor does it return the address. If I remove the device from
the cable, it errors out.
Thank you,
Phillip Kocmoud
Comments
long run with this exact sensor, and it worked 100% once I moved the
pull-up resistor to the sensor.
Regards,
-Bruce
tech@r...
http://www.rentron.com
Original Message
From: "Phillip Kocmoud" <pkocmoud@h...>
To: <basicstamps@yahoogroups.com>
Sent: Thursday, February 20, 2003 5:41 PM
Subject: [noparse][[/noparse]basicstamps] 1-wire Device - Distance Question
> I am attempting to connect a Maxim DS18B20 1-wire temperature sensor to my
> BS2P24. Using me BS2p Demo Board I don't have a problem communication with
> the sensor. Then I placed a sensor at the ends of separate 25ft and 50ft
> runs of CAT5 Twisted Pair computer network wire. 3 wires were all that were
> needed. +5v, GND, and the 1-wire communication line. I cannot get a
> response. I measured the wire and there is very little resistance and the
> connections appear correct. If I plug the sensor to the Demo board and
> attach my extension without a device on the end, I get the same result as
> with the device connected to the end of the cable. What am I missing?
>
> PS. of interesting note, I used the code from the Basic Stamp Manual to
> retrieve the devices serial number. It runs fine with the device connected
> locally. When the sensor is remote it doesn't error out due to no 1-wire
> device detected, nor does it return the address. If I remove the device from
> the cable, it errors out.
>
> Thank you,
>
> Phillip Kocmoud
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and Body
of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
The pullup resistor has to charge up the capacitance of the cable, so
a lower value there makes the transitions from low to high level
faster, enough to meet the demanding 1-wire specs.
One-wire hardware was not originally designed to drive long cables.
It is an open drain logic that operates single ended at the
equivalent of about 10000 baud. Ouch! It is a side benefit that
people make it work on long cables at all.
-- Tracy
>I am attempting to connect a Maxim DS18B20 1-wire temperature sensor to my
>BS2P24. Using me BS2p Demo Board I don't have a problem communication with
>the sensor. Then I placed a sensor at the ends of separate 25ft and 50ft
>runs of CAT5 Twisted Pair computer network wire. 3 wires were all that were
>needed. +5v, GND, and the 1-wire communication line. I cannot get a
>response. I measured the wire and there is very little resistance and the
>connections appear correct. If I plug the sensor to the Demo board and
>attach my extension without a device on the end, I get the same result as
>with the device connected to the end of the cable. What am I missing?
>
>PS. of interesting note, I used the code from the Basic Stamp Manual to
>retrieve the devices serial number. It runs fine with the device connected
>locally. When the sensor is remote it doesn't error out due to no 1-wire
>device detected, nor does it return the address. If I remove the device from
>the cable, it errors out.
>
>Thank you,
>
>Phillip Kocmoud
Original Message
From: Tracy Allen [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=nIHJIcVVgPQsY3t3Q3Y-1uhwap_c9heJs9XGd453vi4Ycv0ciOu7ThE-2L8vL14VasHnntOcTOIG-wc]tracy@e...[/url
Sent: Thursday, February 20, 2003 7:11 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] 1-wire Device - Distance Question
Try a lower resistance pullup on the data line, say 1000 or 820 ohms.
The pullup resistor has to charge up the capacitance of the cable, so
a lower value there makes the transitions from low to high level
faster, enough to meet the demanding 1-wire specs.
One-wire hardware was not originally designed to drive long cables.
It is an open drain logic that operates single ended at the
equivalent of about 10000 baud. Ouch! It is a side benefit that
people make it work on long cables at all.
-- Tracy
>I am attempting to connect a Maxim DS18B20 1-wire temperature sensor to my
>BS2P24. Using me BS2p Demo Board I don't have a problem communication with
>the sensor. Then I placed a sensor at the ends of separate 25ft and 50ft
>runs of CAT5 Twisted Pair computer network wire. 3 wires were all that were
>needed. +5v, GND, and the 1-wire communication line. I cannot get a
>response. I measured the wire and there is very little resistance and the
>connections appear correct. If I plug the sensor to the Demo board and
>attach my extension without a device on the end, I get the same result as
>with the device connected to the end of the cable. What am I missing?
>
>PS. of interesting note, I used the code from the Basic Stamp Manual to
>retrieve the devices serial number. It runs fine with the device connected
>locally. When the sensor is remote it doesn't error out due to no 1-wire
>device detected, nor does it return the address. If I remove the device
from
>the cable, it errors out.
>
>Thank you,
>
>Phillip Kocmoud
To UNSUBSCRIBE, just send mail to:
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conductor cable would be better as it would have lower inductance. 50
ft is quite far for this technology and if you have any noisy
equipment nearby expect erratic errors.
Jason
--- In basicstamps@yahoogroups.com, Tracy Allen <tracy@e...> wrote:
> Try a lower resistance pullup on the data line, say 1000 or 820
ohms.
> The pullup resistor has to charge up the capacitance of the cable,
so
> a lower value there makes the transitions from low to high level
> faster, enough to meet the demanding 1-wire specs.
>
> One-wire hardware was not originally designed to drive long cables.
> It is an open drain logic that operates single ended at the
> equivalent of about 10000 baud. Ouch! It is a side benefit that
> people make it work on long cables at all.
>
> -- Tracy
>
>
> >I am attempting to connect a Maxim DS18B20 1-wire temperature
sensor to my
> >BS2P24. Using me BS2p Demo Board I don't have a problem
communication with
> >the sensor. Then I placed a sensor at the ends of separate 25ft
and 50ft
> >runs of CAT5 Twisted Pair computer network wire. 3 wires were all
that were
> >needed. +5v, GND, and the 1-wire communication line. I cannot get a
> >response. I measured the wire and there is very little resistance
and the
> >connections appear correct. If I plug the sensor to the Demo board
and
> >attach my extension without a device on the end, I get the same
result as
> >with the device connected to the end of the cable. What am I
missing?
> >
> >PS. of interesting note, I used the code from the Basic Stamp
Manual to
> >retrieve the devices serial number. It runs fine with the device
connected
> >locally. When the sensor is remote it doesn't error out due to no
1-wire
> >device detected, nor does it return the address. If I remove the
device from
> >the cable, it errors out.
> >
> >Thank you,
> >
> >Phillip Kocmoud
purpose of twisted pair was to cancel noise. What is the best method of
wiring it up? Just use 3 wires, leave the rest open. or Use 1 wire form each
pair and ground the other at both ends. or something else?
Original Message
From: jbirnsch <jbirnsch@v...> [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=4pHR9XnZkFxgeQyd8-ItsG2zr1VxjyQ8zbLfQvhP9D8Vhb7cB3fD8a8omErOPWz5AyM-YwK7YO82zn8]jbirnsch@v...[/url
Sent: Thursday, February 20, 2003 7:36 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] Re: 1-wire Device - Distance Question
Your CAT 5 cable uses solid conductors. A shielded, stranded, multi
conductor cable would be better as it would have lower inductance. 50
ft is quite far for this technology and if you have any noisy
equipment nearby expect erratic errors.
Jason
--- In basicstamps@yahoogroups.com, Tracy Allen <tracy@e...> wrote:
> Try a lower resistance pullup on the data line, say 1000 or 820
ohms.
> The pullup resistor has to charge up the capacitance of the cable,
so
> a lower value there makes the transitions from low to high level
> faster, enough to meet the demanding 1-wire specs.
>
> One-wire hardware was not originally designed to drive long cables.
> It is an open drain logic that operates single ended at the
> equivalent of about 10000 baud. Ouch! It is a side benefit that
> people make it work on long cables at all.
>
> -- Tracy
>
>
> >I am attempting to connect a Maxim DS18B20 1-wire temperature
sensor to my
> >BS2P24. Using me BS2p Demo Board I don't have a problem
communication with
> >the sensor. Then I placed a sensor at the ends of separate 25ft
and 50ft
> >runs of CAT5 Twisted Pair computer network wire. 3 wires were all
that were
> >needed. +5v, GND, and the 1-wire communication line. I cannot get a
> >response. I measured the wire and there is very little resistance
and the
> >connections appear correct. If I plug the sensor to the Demo board
and
> >attach my extension without a device on the end, I get the same
result as
> >with the device connected to the end of the cable. What am I
missing?
> >
> >PS. of interesting note, I used the code from the Basic Stamp
Manual to
> >retrieve the devices serial number. It runs fine with the device
connected
> >locally. When the sensor is remote it doesn't error out due to no
1-wire
> >device detected, nor does it return the address. If I remove the
device from
> >the cable, it errors out.
> >
> >Thank you,
> >
> >Phillip Kocmoud
To UNSUBSCRIBE, just send mail to:
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Original Message
From: tech@r... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=iT1r251lThRmqBfxEG44hh5cujBpzOYxL9I_E_tpXFHg2VdU_bknAEprNzZXsnjK4-pkpBemgH9zrvs]tech@r...[/url
Sent: Thursday, February 20, 2003 7:10 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] 1-wire Device - Distance Question
Have you tried placing the pull-up resistor on the sensor end..? I have a
long run with this exact sensor, and it worked 100% once I moved the
pull-up resistor to the sensor.
Regards,
-Bruce
tech@r...
http://www.rentron.com
Original Message
From: "Phillip Kocmoud" <pkocmoud@h...>
To: <basicstamps@yahoogroups.com>
Sent: Thursday, February 20, 2003 5:41 PM
Subject: [noparse][[/noparse]basicstamps] 1-wire Device - Distance Question
> I am attempting to connect a Maxim DS18B20 1-wire temperature sensor to my
> BS2P24. Using me BS2p Demo Board I don't have a problem communication with
> the sensor. Then I placed a sensor at the ends of separate 25ft and 50ft
> runs of CAT5 Twisted Pair computer network wire. 3 wires were all that
were
> needed. +5v, GND, and the 1-wire communication line. I cannot get a
> response. I measured the wire and there is very little resistance and the
> connections appear correct. If I plug the sensor to the Demo board and
> attach my extension without a device on the end, I get the same result as
> with the device connected to the end of the cable. What am I missing?
>
> PS. of interesting note, I used the code from the Basic Stamp Manual to
> retrieve the devices serial number. It runs fine with the device connected
> locally. When the sensor is remote it doesn't error out due to no 1-wire
> device detected, nor does it return the address. If I remove the device
from
> the cable, it errors out.
>
> Thank you,
>
> Phillip Kocmoud
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
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Regards,
-Bruce
tech@r...
http://www.rentron.com
Original Message
From: "Phillip Kocmoud" <pkocmoud@h...>
To: <basicstamps@yahoogroups.com>
Sent: Thursday, February 20, 2003 6:54 PM
Subject: RE: [noparse][[/noparse]basicstamps] 1-wire Device - Distance Question
> What value resistor?
>
>
Original Message
> From: tech@r... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=Xxmqy5RS9xhcZVA1mx8JT13TfAQaYWwZx6azNClCqYjBFcQvV5SqpAL0XxnCiyOILMpva9wurA]tech@r...[/url
> Sent: Thursday, February 20, 2003 7:10 PM
> To: basicstamps@yahoogroups.com
> Subject: Re: [noparse][[/noparse]basicstamps] 1-wire Device - Distance Question
>
>
> Have you tried placing the pull-up resistor on the sensor end..? I have a
> long run with this exact sensor, and it worked 100% once I moved the
> pull-up resistor to the sensor.
>
> Regards,
>
> -Bruce
> tech@r...
> http://www.rentron.com
>
>
Original Message
> From: "Phillip Kocmoud" <pkocmoud@h...>
> To: <basicstamps@yahoogroups.com>
> Sent: Thursday, February 20, 2003 5:41 PM
> Subject: [noparse][[/noparse]basicstamps] 1-wire Device - Distance Question
>
>
> > I am attempting to connect a Maxim DS18B20 1-wire temperature sensor to my
> > BS2P24. Using me BS2p Demo Board I don't have a problem communication with
> > the sensor. Then I placed a sensor at the ends of separate 25ft and 50ft
> > runs of CAT5 Twisted Pair computer network wire. 3 wires were all that
> were
> > needed. +5v, GND, and the 1-wire communication line. I cannot get a
> > response. I measured the wire and there is very little resistance and the
> > connections appear correct. If I plug the sensor to the Demo board and
> > attach my extension without a device on the end, I get the same result as
> > with the device connected to the end of the cable. What am I missing?
> >
> > PS. of interesting note, I used the code from the Basic Stamp Manual to
> > retrieve the devices serial number. It runs fine with the device connected
> > locally. When the sensor is remote it doesn't error out due to no 1-wire
> > device detected, nor does it return the address. If I remove the device
> from
> > the cable, it errors out.
> >
> > Thank you,
> >
> > Phillip Kocmoud
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in the Subject and
> Body of the message will be ignored.
> >
> >
> > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
> >
> >
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
> Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
>
> To UNSUBSCRIBE, just send mail to:
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> from the same email address that you subscribed. Text in the Subject and Body
of the message will be ignored.
>
>
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>
>