Shadin flowmeter problems - anyone else sees this?

I have used a Microflo for 4000 hours now. I have found that unless
you leave power on for about one minute after setting FOB, the gal
remaining, or the fuel used, I can't remember which, will not be
correct. Yes, it is EEPROM memory, and does not need power to hold
data, but seems to need power for a little bit to insure the storage.


On Thu, 30 Oct 2003 12:39:02 +0000, Peter
wrote:

Hi,

I've had a Shadin Microflo for a year and a half, and it has what
looks like a hardware or software bug: after setting a new FOB figure,
waiting for it to save it, turning off power, turning power back on,
it has lost the new FOB setting and has reverted to the original FOB
setting which was there before I started to change it.

There is a strong correlation between how long the unit has been ON
(or OFF) since the FOB was set, and losing the data: the longer one
waits, the less likely it is to get lost.

I have now had FOUR of these changed (under warranty) and they all do
it. Sometimes one has to set the FOB (at fill-up time) ten times or
more before it "sticks" in the memory.

Shadin always respond with a standard reply asking for serial number
and other into and don't acknowledge any knowledge of this. They have
however confirmed that there is no battery which might go flat, so I
assume it is an EEPROM/FLASH, in which case (I have designed lots of
electronic products) it would appear a pretty serious "feature".

Has anyone else seen this?


Peter.

Just a guess but EEPROM can be very slow indeed. Depending on the exact part
number, it may not even be possible to change a single location in the chip.
This means that you have to read the entire contents (or a large part) of
the chip, change the value you need to update and then write it all back
again. This is a real pain and can take several seconds to complete.

I would suggest you wait about a minute before turning off the device so
that it has time to go through this procedure.

Most programmer will display some thing like "Updating . . " while the
update is in progress and the "Done" when complete so that you know what is
going on.

Steve



"Peter" wrote in message
...
Hi,

I've had a Shadin Microflo for a year and a half, and it has what
looks like a hardware or software bug: after setting a new FOB figure,
waiting for it to save it, turning off power, turning power back on,
it has lost the new FOB setting and has reverted to the original FOB
setting which was there before I started to change it.

There is a strong correlation between how long the unit has been ON
(or OFF) since the FOB was set, and losing the data: the longer one
waits, the less likely it is to get lost.

I have now had FOUR of these changed (under warranty) and they all do
it. Sometimes one has to set the FOB (at fill-up time) ten times or
more before it "sticks" in the memory.

Shadin always respond with a standard reply asking for serial number
and other into and don't acknowledge any knowledge of this. They have
however confirmed that there is no battery which might go flat, so I
assume it is an EEPROM/FLASH, in which case (I have designed lots of
electronic products) it would appear a pretty serious "feature".

Has anyone else seen this?


Peter.
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"Peter" wrote in message
...

I've had a Shadin Microflo for a year and a half, and it has what
looks like a hardware or software bug: after setting a new FOB figure,
waiting for it to save it, turning off power, turning power back on,
it has lost the new FOB setting and has reverted to the original FOB
setting which was there before I started to change it.

Yes. I think I've seen that on a Digiflo. I put it down to finger trouble
but it happened twice.

Interestingly, after you program the Full setting (rarely used in practice),
the manual advises

"NOTE: Do not turn the power off to the computer for
approximately one minute. This will ensure that the unit has
enough time to store the proper figures into the program."

but it doesn't explicitly say the same for normal pre-flight ops.

Julian Scarfe