Sigma computers and distances...

The distance is derived from counting the number of impulses from the magnet on the spoke and
multiplying it by the wheel circumference. The speed is derived from that distance divided by the
elapsed time. If one is correct but not the other, then the internal clock in the Sigma must be
faulty (very unlikely!). Does it display the time correctly?

"David Roy" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Apologies if this has already been asked 73 times in the last week (I have googled, but not found
an answer) - do Sigma computers calculate distance seperately from speed? The thing is that I got
a 1200 (wireless) for Christmas, and even though it seems roughly right, or at least plausible,
on speed, it's wildly out on the distance I'm covering. It records the distance to work as
something like 30/40% of the actual distance. Multiplying the wheel size up to get the right
distance would give me

speed

Quoted message said:

readings somewhere in the region of 75kmh, which seems unlikely in the middle of town. Is this a
known problem? Is there a known solution? Could it just be down to the fact that it's damn cold at
the moment, and

it

Quoted message said:

doesn't work well under 0°?

David

Are you sure that the computer is working the entire distance. I have a BC1600 with the wireless
setup. It worked quite well for the first month or so. Then I also discovered that the distance
recorded was wrong. When looking at it closer I found that the damn thing stopped working after
awhile. Sometimes it worked for the entire ride, sometimes it could stop working after 15-20 mins.
After a few more days it started to "freeze" on a certain speed, but didn't record any distance. It
could have something to do with the temperature as I'm in Norway where it can get quite low at this
time of year. But I've been on rides down to -7C where the damn thing has been working fluently for
at least two hours. When I'm on the wired setup it's working fluenly all the time so it has nothing
to do with the computer itself. I've been in touch with the factory in Germany and they told me to
return the wireless setup to them and they would send me a new one. I so did yesterday. I've also
heard from a biker in the US having had the same problems, but the problems disappeared after
getting a new RDS setup. Hjalmar

David Roy <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

Apologies if this has already been asked 73 times in the last week (I have googled, but not found
an answer) - do Sigma computers calculate distance seperately from speed? The thing is that I got
a 1200 (wireless) for Christmas, and even though it seems roughly right, or at least plausible, on
speed, it's wildly out on the distance I'm covering. It records the distance to work as something
like 30/40% of the actual distance. Multiplying the wheel size up to get the right distance would
give me speed readings somewhere in the region of 75kmh, which seems unlikely in the middle of
town. Is this a known problem? Is there a known solution? Could it just be down to the fact that
it's damn cold at the moment, and it doesn't work well under 0°?

Does the speed start out OK then apparently drop or fail altogether in the latter stages of your
journey? There are apparently issues with Sigma wireless computers in the cold. There was a thread
about this in
r.b.t. last month. See makeashorterlink.commakeashorterlink.comOpen ↗ or (full version) groups.google.co.ukgroupsOpen ↗
Bb.93051%24G77.33845%40amsnews02.chello.com&rnum=3&prev=/groups%3Fhl%3Den%26lr%3D%26ie%3DISO-
8859-1%26q%3Dwireless%2Bcold%26meta%3Dgroup%253Drec.bicycles.tech

--
Dave...

"Dave Kahn" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

David Roy <[email hidden]> wrote in message

news:<[email hidden]>...

Quoted message said:

Quoted message said:

Apologies if this has already been asked 73 times in the last week (I

have

Quoted message said:

Quoted message said:

googled, but not found an answer) - do Sigma computers calculate

distance

Quoted message said:

Quoted message said:

seperately from speed? The thing is that I got a 1200 (wireless) for Christmas, and even though
it seems roughly right, or at least

plausible,

Quoted message said:

Quoted message said:

on speed, it's wildly out on the distance I'm covering. It records the distance to work as
something like 30/40% of the actual distance. Multiplying the wheel size up to get the right
distance would give me

speed

Quoted message said:

Quoted message said:

readings somewhere in the region of 75kmh, which seems unlikely in the middle of town. Is this a
known problem? Is there a known solution? Could it just be down to the fact that it's damn cold
at the moment, and

it

Quoted message said:

Quoted message said:

doesn't work well under 0°?

Does the speed start out OK then apparently drop or fail altogether in the latter stages of your
journey? There are apparently issues with Sigma wireless computers in the cold. There was a thread
about this in
r.b.t. last month. See makeashorterlink.commakeashorterlink.comOpen ↗ or (full version)

groups.google.co.ukgroupsOpen ↗
adm=vg_Bb.93051%24G77.33845%40amsnews02.chello.com&rnum=3&prev=/groups%3Fhl%3Den%26lr%3D%26ie%3DISO-
8859-1%26q%3Dwireless%2Bcold%26meta%3Dgroup%253Drec.bicycles.tech

Quoted message said:

--
Dave...

Well, it was me that started that thread. I've tried to change batteries but that didn't help at
all. The speed starts out OK. After some time, can be 15 minutes or it can work for two hours it
starts to fail. At first it just started to go down slowly until it ended at zero, but after being
like that for a couple of weeks the speed started to "freeze" to a fixed speed. At that time I
believe the computer stopped recording any data. If I took it off the mount it took nearly one minte
before the speed went down to zero (very strange). If I put it back on it could work for a few
minutes then fail again. If I changed over to the wired setup (I had both on at the same time) it
worked as it should. Hjalmar

"David Roy" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Apologies if this has already been asked 73 times in the last week (I have googled, but not found
an answer) - do Sigma computers calculate distance seperately from speed? The thing is that I got
a 1200 (wireless) for Christmas, and even though it seems roughly right, or at least plausible,
on speed, it's wildly out on the distance I'm covering. It records the distance to work as
something like 30/40% of the actual distance. Multiplying the wheel size up to get the right
distance would give me

speed

Quoted message said:

readings somewhere in the region of 75kmh, which seems unlikely in the middle of town. Is this a
known problem? Is there a known solution? Could it just be down to the fact that it's damn cold at
the moment, and

it

Quoted message said:

doesn't work well under 0°?

David

Replacing batteries helped but only for a couple of weeks so I replaced my wireless (BC800) with a
wired version (BC1200) which resolved the issue for me. I think from what i've read that the wirless
sender unit is the culprit sadly the two i have use different interfaces so I can't try the old
BC800 on a wired mount.

TJ

"Ric" <[email hidden]> wrote in :"]news:[email hidden]:

Quoted message said:

The distance is derived from counting the number of impulses from the magnet on the spoke and
multiplying it by the wheel circumference. The speed is derived from that distance divided by the
elapsed time. If one is correct but not the other, then the internal clock in the Sigma must be
faulty (very unlikely!). Does it display the time correctly?

Thanks to everyone for the replies...

The clock seems fine - or at least it keeps good time... What really puzzles me is that the speed is
OK but the distance is wrong - if speed is calculated from distance covered divided by time, it
should surely also be wrong...

David

"Hjalmar Duklæt" <[email hidden]> wrote in
:"]news:[email hidden]:

Quoted message said:

"David Roy" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Apologies if this has already been asked 73 times in the last week (I have googled, but not found
an answer) - do Sigma computers calculate distance seperately from speed? The thing is that I got
a 1200 (wireless) for Christmas, and even though it seems roughly right, or at least plausible,
on speed, it's wildly out on the distance I'm covering. It records the distance to work as
something like 30/40% of the actual distance. Multiplying the wheel size up to get the right
distance would give me

speed

Quoted message said:

readings somewhere in the region of 75kmh, which seems unlikely in the middle of town. Is this a
known problem? Is there a known solution? Could it just be down to the fact that it's damn cold
at the moment, and

it

Quoted message said:

doesn't work well under 0°?

David

Are you sure that the computer is working the entire distance. I have a BC1600 with the
wireless setup. It worked quite well for the first month or so. Then I also discovered that the
distance recorded was wrong. When looking at it closer I found that the damn thing stopped
working after awhile.

Well, no I'm not... I'm only riding round town - 45m per journey at most
- and with a lot of stopping and starting for traffic lights and so on. (I come down firmly on the
side of not tempting fate to side-swipe me with a car.) What seems to happen is that it freezes
from time to time, either registering the same speed for a while, whether I slow down or speed up,
or, more rarely, dropping the speed down to 0 and back.

Sometimes it worked for the entire ride,

Quoted message said:

sometimes it could stop working after 15-20 mins. After a few more days it started to "freeze" on
a certain speed, but didn't record any distance. It could have something to do with the
temperature as I'm in Norway where it can get quite low at this time of year. But I've been on
rides down to -7C where the damn thing has been working fluently for at least two hours. When I'm
on the wired setup it's working fluenly all the time so it has nothing to do with the computer
itself. I've been in touch with the factory in Germany and they told me to return the wireless
setup to them and they would send me a new one. I so did yesterday. I've also heard from a biker
in the US having had the same problems, but the problems disappeared after getting a new RDS
setup. Hjalmar

I suspect that the factory is the next stop for me. I'd be sorry to install wires though - the geek
in me loves the wireless set-up.

David

[email hidden] (Dave Kahn) wrote in
:"]news:[email hidden]:

Quoted message said:

David Roy <[email hidden]> wrote in message
news:<[email hidden]>...

Quoted message said:

Apologies if this has already been asked 73 times in the last week (I have googled, but not found
an answer) - do Sigma computers calculate distance seperately from speed? The thing is that I got
a 1200 (wireless) for Christmas, and even though it seems roughly right, or at least plausible,
on speed, it's wildly out on the distance I'm covering. It records the distance to work as
something like 30/40% of the actual distance. Multiplying the wheel size up to get the right
distance would give me speed readings somewhere in the region of 75kmh, which seems unlikely in
the middle of town. Is this a known problem? Is there a known solution? Could it just be down to
the fact that it's damn cold at the moment, and it doesn't work well under 0°?

Does the speed start out OK then apparently drop or fail altogether in the latter stages of your
journey? There are apparently issues with Sigma wireless computers in the cold. There was a thread
about this in
r.b.t. last month. See makeashorterlink.commakeashorterlink.comOpen ↗ or (full version) groups.google.co.ukgroupsOpen ↗
8&threadm=vg_Bb.9305
1%24G77.33845%40amsnews02.chello.com&rnum=3&prev=/groups%3Fhl%3Den%26lr
%3D%26ie%3DISO-8859-1%26q%3Dwireless%2Bcold%26meta%3Dgroup%253Drec.bicy
cles.tech

It actually seems to fail intermittently throughout a relatively short (45m max) ride. But
certainly, it registers shorter distances in colder weather (based on one week's experience).

David

David Roy said:

The clock seems fine - or at least it keeps good time... What really puzzles me is that the speed
is OK but the distance is wrong - if speed is calculated from distance covered divided by time, it
should surely also be wrong...

The wheel size has to be multiplied by 0.6214 to get correct readings in miles. The miles/km
indicator isn't actually linked to the calculating algorithm on Sigmas.

Zog The Undeniable <[email hidden]> wrote in
:"]news:[email hidden]:

Quoted message said:

David Roy said:

The clock seems fine - or at least it keeps good time... What really puzzles me is that the speed
is OK but the distance is wrong - if speed is calculated from distance covered divided by time,
it should surely also be wrong...

The wheel size has to be multiplied by 0.6214 to get correct readings in miles. The miles/km
indicator isn't actually linked to the calculating algorithm on Sigmas.

Absolutely - but I actually *want* the speed in kmh, and the distance in km. Not to mention which
the thing's not overestimating the distance by a half (which would be the case if I'd mis-set it for
miles) but underestimating the distance by a factor of 2 or 3.

David