"David Lord" wrote in message
news:gnbbu8-qne@me6000g.home.lordynet.org...
[]
I've not put a scope on the pps but I added an extra section
of cable from my Sure GPS, 18 m of 4 x pair telephone cable.
I will need that length to reach from the GPS down to my PCs.
In the process the offset ju
David J Taylor wrote:
"David Lord" wrote in message
news:gnbbu8-qne@me6000g.home.lordynet.org...
[]
I've not put a scope on the pps but I added an extra section
of cable from my Sure GPS, 18 m of 4 x pair telephone cable.
I will need that length to reach from the GPS down to my PCs.
In th
David Lord wrote:
David J Taylor wrote:
My Oncore docs give a suggested circuit with a 74HC132:
GPS-6_1PPS --+-++--- MAX232_T2in
| ||
| 4 +-- |
1 +-- 3 & o--+
David J Taylor wrote:
"David Lord" wrote in message
news:gnbbu8-qne@me6000g.home.lordynet.org...
[]
I've not put a scope on the pps but I added an extra section
of cable from my Sure GPS, 18 m of 4 x pair telephone cable.
I will need that length to reach from the GPS down to my PCs.
In th
David J Taylor wrote:
Nearly that, but I'm splitting the power and planning on
having +9V and -Ve on two of the lines and a 5V regulator
since some of the GPS modules with interfaces take over
200mA so common OV with the -Ve at the far end should
remove any effect from voltage drop over that len
Nearly that, but I'm splitting the power and planning on
having +9V and -Ve on two of the lines and a 5V regulator
since some of the GPS modules with interfaces take over
200mA so common OV with the -Ve at the far end should
remove any effect from voltage drop over that length of
cable.
OK - us
"unruh" wrote in message
news:2GnPq.9424$wy@newsfe21.iad...
[]
No, the Sure unit outputs a 100 ms wide pulse. I have not measured its
Sorry, it risetime width.
risetime. The stated accuracy for "time" is 20 ns, but the Web page
does
not state where that 20 ns is measured - it may be i
"unruh" wrote in message
news:wlmPq.80363$cn1.31...@newsfe12.iad...
[]
If rise time is preserved, the pulse is preserved.
If there are no reflections, but in general, yes.
A 10us pulse will
begin to be wiped out once the rise time gets longer than 10us.
If the rs232 really filters so strong
On 2012-01-11, David J Taylor wrote:
> "unruh" wrote in message
> news:bMjPq.61168$ee3.12...@newsfe04.iad...
> []
>> Just like the rs232 specs say at least -3V to +3 V for the signals, when
>> most rs232 cards will accept +.5V to +2 V for the transition levels.
>> What the specs say and what the
On 2012-01-11, David J Taylor wrote:
> "unruh" wrote in message
> news:yHjPq.70127$8o1.15...@newsfe07.iad...
> []
>> For timing it is only the rise time that is important. The length of the
>> pulse is irrelevant, unless your Hardware/software requires a given
>> length pulse in order to recogni
"unruh" wrote in message
news:bMjPq.61168$ee3.12...@newsfe04.iad...
[]
Just like the rs232 specs say at least -3V to +3 V for the signals, when
most rs232 cards will accept +.5V to +2 V for the transition levels.
What the specs say and what the card does need not be the same. People
have claime
"unruh" wrote in message
news:yHjPq.70127$8o1.15...@newsfe07.iad...
[]
For timing it is only the rise time that is important. The length of the
pulse is irrelevant, unless your Hardware/software requires a given
length pulse in order to recognize and interrupt ( and if it did , it
would be brok
On 2012-01-11, David J Taylor wrote:
> "unruh" wrote in message
> news:7Y2Pq.10307$xs3.7...@newsfe17.iad...
> []
>> No, I was talking about the width of the edge transition. Neither the
>> accuracy of that transition, nor the width of the pulse. the former one
>> cannot know unless one has anoth
On 2012-01-11, David J Taylor wrote:
> "unruh" wrote in message
> news:dJ0Pq.27842$kp3.26...@newsfe13.iad...
> []
>> Yes, I was talking about the width of the pulse's rising edge.
>> It is the risetime that is of first importance for timing. The length of
>> the pulse
>> only is important in ho
"unruh" wrote in message
news:RK0Pq.27843$kp3.18...@newsfe13.iad...
[]
Who cares what the width is? It is the risetime that is important for
timing. And it is the smearing of the risetime that messes up the
timing. If the smearing is so bad that the pulse starts to loose its
shape, you are tot
"unruh" wrote in message
news:dJ0Pq.27842$kp3.26...@newsfe13.iad...
[]
Yes, I was talking about the width of the pulse's rising edge.
It is the risetime that is of first importance for timing. The length of
the pulse
only is important in how the serial port identifies interrupts ( and I
guess
"unruh" wrote in message
news:7Y2Pq.10307$xs3.7...@newsfe17.iad...
[]
No, I was talking about the width of the edge transition. Neither the
accuracy of that transition, nor the width of the pulse. the former one
cannot know unless one has another gps whose accuracy one knows, and the
latter is
On 2012-01-10, E-Mail Sent to this address will be added to the BlackLists
wrote:
> unruh wrote:
>> David J Taylor wrote:
>>> "David Woolley" wrote:
>>> pulse over the length of line he talks about should be no
>>> problem at all (but a microsecond-wide pulse might).
>>> The timing PPS I've see
Terje Mathisen wrote:
David Lord wrote:
When I get around to assembly of my 2-to-6 rs232 expander
I'll scope with both short and long cables and I've also
rs422 MC3486/7 to try.
I'm doubtful my modern scope can catch and display a 5 us
pulse with period of 1 sec.
That should not be too hard,
unruh wrote:
> David J Taylor wrote:
>> "David Woolley" wrote:
>> pulse over the length of line he talks about should be no
>> problem at all (but a microsecond-wide pulse might).
>> The timing PPS I've seen are in the tens of milliseconds wide.
>> If there is overshoot, perhaps a capacitor to .
On 2012-01-10, Terje Mathisen <"terje.mathisen at tmsw.no"> wrote:
> unruh wrote:
>> On 2012-01-10, David J Taylor wrote:
>>> pulse over the length of line he talks about should be no problem at all
>>> (but a microsecond-wide pulse might). The timing PPS I've seen are in the
>>> tens of millisec
On 2012-01-10, David J Taylor wrote:
> "unruh" wrote in message
> news:eg%Oq.48484$2e7.22...@newsfe18.iad...
> []
>>> pulse over the length of line he talks about should be no problem at
>>> all
>>> (but a microsecond-wide pulse might). The timing PPS I've seen are in
>>> the
>>> tens of mill
On 2012-01-10, David J Taylor wrote:
> "unruh" wrote in message
> news:yb%Oq.28020$d52.7...@newsfe22.iad...
> []
>>> I was expecting that, for timing purposes, the four pairs would be used
>>> as:
>>>
>>> - TXD/ground
>>> - RXD/ground
>>> - DCD/ground
>>> - unused
>>>
>>> i.e. that every relevan
David Lord wrote:
When I get around to assembly of my 2-to-6 rs232 expander
I'll scope with both short and long cables and I've also
rs422 MC3486/7 to try.
I'm doubtful my modern scope can catch and display a 5 us
pulse with period of 1 sec.
That should not be too hard, even my 20-30 (?) year
unruh wrote:
On 2012-01-10, David J Taylor wrote:
pulse over the length of line he talks about should be no problem at all
(but a microsecond-wide pulse might). The timing PPS I've seen are in the
tens of milliseconds wide. If there is overshoot, perhaps a capacitor to
Did you mean 10s of n
"unruh" wrote in message
news:eg%Oq.48484$2e7.22...@newsfe18.iad...
[]
pulse over the length of line he talks about should be no problem at
all
(but a microsecond-wide pulse might). The timing PPS I've seen are in
the
tens of milliseconds wide. If there is overshoot, perhaps a capacitor
to
"unruh" wrote in message
news:yb%Oq.28020$d52.7...@newsfe22.iad...
[]
I was expecting that, for timing purposes, the four pairs would be used
as:
- TXD/ground
- RXD/ground
- DCD/ground
- unused
i.e. that every relevant RS-232 line was carried with a ground on the
twisted pair. This would be
On 2012-01-10, David J Taylor wrote:
> "David Woolley" wrote in message
> news:jefokf$9m0$1...@dont-email.me...
> []
>> To the extent those constraints don't apply and both ends are terminated
>> well above the characteristic impedance, the output voltage actually
>> goes up in a staircase, wi
On 2012-01-10, David J Taylor wrote:
>> On Jan 8, 2012, at 11:45 PM, David J Taylor wrote:
>>> Chris, it also occurs to me to enquire exactly how the RS-232 data is
>>> being carried over the cat-5 cable. What is the wiring?
>>
>> Searching for "RS232 over RJ45" suggests the standard pinout is k
David J Taylor wrote:
My Oncore docs give a suggested circuit with a 74HC132:
GPS-6_1PPS --+-++--- MAX232_T2in
| ||
| 4 +-- |
1 +-- 3 & o--+
| & o-- R
On Jan 9, 2012, at 11:25 PM, David J Taylor wrote:
>> Searching for "RS232 over RJ45" suggests the standard pinout is known as
>> EIA/TIA 561.
>> Basically, it closely resembles the EIA/TIA 574 (DB9) wiring, but DSR and RI
>> have been combined.
>
> I was expecting that, for timing purposes, the
My Oncore docs give a suggested circuit with a 74HC132:
GPS-6_1PPS --+-++--- MAX232_T2in
| ||
| 4 +-- |
1 +-- 3 & o--+
| & o-- R=10k --+-- 6
David J Taylor wrote:
"David Woolley" wrote in message
news:jefokf$9m0$1...@dont-email.me...
[]
To the extent those constraints don't apply and both ends are
terminated well above the characteristic impedance, the output voltage
actually goes up in a staircase, with the steps being the round
"David Woolley" wrote in message
news:jefokf$9m0$1...@dont-email.me...
[]
To the extent those constraints don't apply and both ends are terminated
well above the characteristic impedance, the output voltage actually
goes up in a staircase, with the steps being the round trip time.
Some other
On Jan 8, 2012, at 11:45 PM, David J Taylor wrote:
Chris, it also occurs to me to enquire exactly how the RS-232 data is
being carried over the cat-5 cable. What is the wiring?
Searching for "RS232 over RJ45" suggests the standard pinout is known as
EIA/TIA 561.
Basically, it closely resemble
E-Mail Sent to this address will be added to the BlackLists wrote:
I'd have to dig up the specs, but Cat5e is usually around
mid 50's pf per meter (@ some frequency).
That's only really valid for signals with rise times much longer than
the round trip time on the cable. With 50 ft and 30V/
Chris Albertson wrote:
Solution: Don't do RS-232 over cat-5. Move the computer. Use a two foot
serial cable and then the same cat-5 cable for a network connection.
RS 422 (balanced) and RS 423 (unbalanced) are intended for such purposes.
___
que
On 2012-01-09, Chris Albertson wrote:
>>
>>
>> With +/- 12VDC RS232 drivers, I've done 800' and 1000' runs
>> of Cat5e @ 19.2Kbps without issues.
>>
>> {On the other hand, on cables designed for RS232 decades before Cat5e,
>> I've had issues at one tenth that far, (~100pf to 200pf / meter)
>>
On 2012-01-09, E-Mail Sent to this address will be added to the BlackLists
wrote:
> David Woolley wrote:
>> Mike S wrote:
>>> unruh wrote:
Make sure you properly terminate the cable with 100 ohms.
Otherwise you will get reflections back and forth along
the cable, and the ca
>
>
> With +/- 12VDC RS232 drivers, I've done 800' and 1000' runs
> of Cat5e @ 19.2Kbps without issues.
>
> {On the other hand, on cables designed for RS232 decades before Cat5e,
> I've had issues at one tenth that far, (~100pf to 200pf / meter)
> at 19.2Kbps.
>
>
What I may have is "self int
David Woolley wrote:
> Mike S wrote:
>> unruh wrote:
>>>
>>> Make sure you properly terminate the cable with 100 ohms.
>>> Otherwise you will get reflections back and forth along
>>> the cable, and the cable will slowly fill with charge,
>>> broadening the pulse by a huge amount.
>>> It may a
On Mon, Jan 9, 2012 at 10:43 AM, Chuck Swiger wrote:
> On Jan 8, 2012, at 11:45 PM, David J Taylor wrote:
> > Chris, it also occurs to me to enquire exactly how the RS-232 data is
> being carried over the cat-5 cable. What is the wiring?
>
> Searching for "RS232 over RJ45" suggests the standard
On Jan 8, 2012, at 11:45 PM, David J Taylor wrote:
> Chris, it also occurs to me to enquire exactly how the RS-232 data is being
> carried over the cat-5 cable. What is the wiring?
Searching for "RS232 over RJ45" suggests the standard pinout is known as
EIA/TIA 561.
Basically, it closely resemb
I think the problem is my long cable. I'm pushing about 80+ feet of
cat-5 cable. Looks like I will either have to move the equipment or
use RS422 drivers at each end. I'm going to try moving the equipment
to where I can use a quality 4 foot cable.
Chris Albertson
Redondo Beach, California
I have a UT+ It does 5V logic level pulses but I connect the TTL
level PPS to a MAX232 chip which converts the levels to +/- 8 volts
I think the problem is my long cable. I'm pushing about 80+ feet of
cat-5 cable. Looks like I will either have to move the equipment or
use RS422 drivers at each
unruh writes:
> He said he was using 80 ft of cat 5 cable. That is 100 ohm cable. To
> get rid of reflections he needs a 100 ohm termination. This has
> nothing to do with 232.
RS232 is not intended to be used with speeds and cable lengths such that
transmission line effects are significant. When
On 1/8/2012 6:48 PM, David Woolley wrote:
> Mike S wrote:
>> On 1/8/2012 5:19 PM, unruh wrote:
>> ...
>>>
>>> Make sure you properly terminate the cable with 100 ohms. Otherwise you
>>> will get reflections back and forth along the cable, and the cable will
>>> slowly fill with charge, broadening
On 2012-01-08, Mike S wrote:
> On 1/8/2012 5:19 PM, unruh wrote:
>> On 2012-01-08, Chris Albertson wrote:
>>> I have a UT+ It does 5V logic level pulses but I connect the TTL
>>> level PPS to a MAX232 chip which converts the levels to +/- 8 volts
>>>
>>> I think the problem is my long cable.
> .
David Woolley writes:
> If you want fast edges to be reproduced accurately, you must do, as
> Unruh says, and terminate the line with its characteristic impedance.
But RS232 drivers won't reliably drive 100 ohm loads. Another possible
problem with RS232 on long runs is 60Hz interference due to gr
Mike S wrote:
On 1/8/2012 5:19 PM, unruh wrote:
...
Make sure you properly terminate the cable with 100 ohms. Otherwise you
will get reflections back and forth along the cable, and the cable will
slowly fill with charge, broadening the pulse by a huge amount. It may
also be that the signal is d
Mike S wrote:
On 1/8/2012 5:19 PM, unruh wrote:
...
Make sure you properly terminate the cable with 100 ohms. Otherwise you
will get reflections back and forth along the cable, and the cable will
slowly fill with charge, broadening the pulse by a huge amount. It may
also be that the signal is d
On 1/8/2012 5:19 PM, unruh wrote:
On 2012-01-08, Chris Albertson wrote:
I have a UT+ It does 5V logic level pulses but I connect the TTL
level PPS to a MAX232 chip which converts the levels to +/- 8 volts
I think the problem is my long cable.
...
Make sure you properly terminate the cable
On 2012-01-08, Chris Albertson wrote:
> On Fri, Jan 6, 2012 at 1:54 PM, E-Mail Sent to this address will be
> added to the BlackLists
> wrote:
>> On 1/6/2012 12:28 PM, unruh wrote:
>>> Eg, your encore pluse is a TTL level pulse (0-3 volt transition)
>>
>> I thought he indicated he had a Oncore UT
On Fri, Jan 6, 2012 at 1:54 PM, E-Mail Sent to this address will be
added to the BlackLists
wrote:
> On 1/6/2012 12:28 PM, unruh wrote:
>> Eg, your encore pluse is a TTL level pulse (0-3 volt transition)
>
> I thought he indicated he had a Oncore UT+ ?
>
> The M12M Oncore specs TTL interface (0 t
On 2012-01-06, Chris Albertson wrote:
> I know you are going to ask so here are the config files
>
> MODE 4
> LAT33 51 54.315
> LONG -118 23 01.782
> HT 25.56 M
> DELAY 50 NS
> ASSERT
> SHMEM /var/log/ntpstats/ONCORE
> POSN3D
> MASK 0
>
Cris:
Re-reading your ntp.oncore configuration file,
On 2012-01-06, unruh wrote:
> Ssure a pulse can go missing. Eg, your encore pluse is a TTL level pulse
> (0-3 volt transition) and your serial port is marginal with that ( the
> standard for serial ports is basically -5 to +5 volt transition) So
> occasionally the hardware misses the transition. O
On 2012-01-06, Chris Albertson wrote:
> I just upgraded to?4.2.6p5@1.2349-o and I'm getting some odd results.
> NTPD has been running for about 12 hours not on a Linux system. ?The
> following three "peers" displays were taken about one minute?apart.
> How do I go about debugging this? ? Where to
On 1/6/2012 9:29 PM, E-Mail Sent to this address will be added to the
BlackLists wrote:
On 1/6/2012 3:18 PM, Mike S wrote:
On 1/6/2012 4:54 PM, E-Mail Sent to this address will be added to the
BlackLists wrote:
On 1/6/2012 12:28 PM, unruh wrote:
Eg, your encore pluse is a TTL level pulse (0-3
"unruh" wrote in message
news:EPINq.55250$mj.40...@newsfe10.iad...
[]
What worries me more is that 999 ms
offset at one point, which suggests that the nmea sentence came too late
and the pulse got associated with the wrong second. (The garmin 18x had
this trouble a lot apparently).
Yes, Bill,
On 1/6/2012 3:18 PM, Mike S wrote:
> On 1/6/2012 4:54 PM, E-Mail Sent to this address will be added to the
> BlackLists wrote:
>> On 1/6/2012 12:28 PM, unruh wrote:
>>> Eg, your encore pluse is a TTL level pulse (0-3 volt transition)
>>
>> I thought he indicated he had a Oncore UT+ ?
>>
>> The M1
On 1/6/2012 4:54 PM, E-Mail Sent to this address will be added to the
BlackLists wrote:
On 1/6/2012 12:28 PM, unruh wrote:
Eg, your encore pluse is a TTL level pulse (0-3 volt transition)
I thought he indicated he had a Oncore UT+ ?
The M12M Oncore specs TTL interface (0 to 3 V)
The UT Pl
On 2012-01-06, E-Mail Sent to this address will be added to the BlackLists
wrote:
> On 1/6/2012 12:28 PM, unruh wrote:
>> Eg, your encore pluse is a TTL level pulse (0-3 volt transition)
>
> I thought he indicated he had a Oncore UT+ ?
>
> The M12M Oncore specs TTL interface (0 to 3 V)
> The UT
On 1/6/2012 12:28 PM, unruh wrote:
> Eg, your encore pluse is a TTL level pulse (0-3 volt transition)
I thought he indicated he had a Oncore UT+ ?
The M12M Oncore specs TTL interface (0 to 3 V)
The UT Plus Oncore TTL specs TTL interface (0 to 5 V)
The GT Plus Oncore specs TTL interface (0 to 5
On Fri, Jan 6, 2012 at 9:48 AM, Chris Albertson
wrote:
> On Fri, Jan 6, 2012 at 1:32 AM, leap235960 wrote:
>> Le vendredi 6 janvier 2012 04:44:36 UTC+1, Chris Albertson a écrit :
>>
>>> ntpq> peers
>>> remote refid st t when poll reach delay offset
>>> jitter
>>> ===
Le vendredi 6 janvier 2012 04:44:36 UTC+1, Chris Albertson a écrit :
> ntpq> peers
> remote refid st t when poll reach delay offset jitter
> ==
> oGPS_ONCORE(0) .GPS.0 l 14 16 35
On Thu, Jan 5, 2012 at 7:44 PM, Chris Albertson
wrote:
> I just upgraded to 4.2.6p5@1.2349-o and I'm getting some odd results.
> NTPD has been running for about 12 hours not on a Linux system. The
Should read "about 12 hours now on a Linux system."
There were some pretty wild swings in the firs
I just upgraded to 4.2.6p5@1.2349-o and I'm getting some odd results.
NTPD has been running for about 12 hours not on a Linux system. The
following three "peers" displays were taken about one minute apart.
How do I go about debugging this? Where to start? The PPS coming
from the Oncore has les
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