SMA EEPROM_d Error fixes [RE-wrenches]

Thu Sep 25 18:04:17 PDT 2003

Wrenches:

In the words of Douglas Adams: "Don't Panic and always remember to pack
your towel".

Background:

In a very limited number of installations we have seen EEPROM_d errors.

The EEPROM_d error is generated when the inverter is trying to write
values from RAM into EEPROM.
Normally the write cycle occurs only at the end of the day when the
production totals for the day are added to the previous data.
(If the inverter sees grid abnormalities it also generates a write
sequence to update the error counters, etc.)
If the write cycle is interrupted then the data is corrupted and the
inverter throws out the bad data and the EEPROM_d error is generated.
The best we can tell is that the error is essentially random but we
have seen a higher incidence of this error in areas that have noisy
power.
Initially we thought there was a correlation to multiple inverter
installations but now we think it is more related to poor power quality
at the site.
Our best guess is that the interruption is caused when grid conditions
(grid voltage, noise, asymmetric waveform, etc.) cause the inverters
anti-islanding routines to kick in during the write cycle.
Please understand that this is very tricky problem that we have not
been able to reliably reproduce in the lab either here at SMA America or
at SMA in Germany.

Solutions:

The existing versions of firmware an EEPROM_d error can be cleared with
a manual reset.
This was covered in one of my earlier wrenches posts and on our web
site as well.
The manual reset can be done in the field (see the tech updates section
our web site for the procedure).
In the vast majority of cases the manual reset solves the problems and
it does not reoccur.
We have, however, seen recurring EEPROM_d errors in a handfull
(literally) of systems.

Obviously the manual method is undesirable so...
We have been working on a new version of firmware that eliminates the
requirement for the manual reset. 
This new version has taken a while because, after we figured out what
was happening, we had to write new firmware and then get UL approval on
the new version.
SMA follows UL 1998 procedures for firmware updates and this means UL
has to review any changes we make to firmware and approve it before we
can ship it to the field.  
The new firmware is Version 8.90 (Srr) / 8.92 (Bfr) and, last week when
Kent was over in Germany, we released it for use on a limited field
trial basis.

Please note that we are trying to be very conservative here to make
sure the cure isn't worse than the disease.

With the new firmware, the EEPROM_d error still occurs but the inverter
just throws away the corrupt data and records the error. 
As in the old firmware, you lose the production data for that day but
not the energy that was generated.
The inverter should restart normally the next time the it is powered up
instead of requiring a manual reset.
Typically this is the next morning but you can always force the restart
by cycling the dc disconnect. 
Since the EEPROM write cycle normally occurs at the end of the day the
EEPROM_d error should not have a significant impact on power production.

Caveats:

For the vast majority of installations we do not recommend updating the
firmware.
IMHO, it is unnecessary and simply not worth the trouble unless the
EEPROM_d error is a recurring problem at that site.
If you have had a site with recurring EEPROM_d errors and would like to
be part of the field trial please contact Jasun Mills at SMA America.

As with all things in life there is no free lunch, so here are the
caveats to upgrading the firmware:
Version 8.90/8.92 will work in both 1800's and 2500's with firmware
version 8.65 and higher.
Inverters with earlier versions of firmware will need to come back here
for a hardware fix before they can be updated.
Fortunately we have not really seen this problem in older units.

If you are using any of the Sunny Boy Control products you >> MAY <<
need to upgrade the firmware in the SBC.
This is really a big bummer since you have to reconfigure your plant
after the upgrade and check to make sure your data map is consistent. 
- For the Sunny Boy Control Light you need to update to firmware
Version 2.17
- For the Sunny Boy Control and Control Plus you need to update to
firmware Version 3.21
- For the Sunny Control Data software you need to update to Version
3.30 
This shouldn't be an issue for newer installations since these are the
current versions of firmware shipping in products and available on our
web site.  

Best REgards,

John Berdner

>>> solarpro at aol.com 9/24/2003 12:50:34 PM >>>

Anybody:

I have been experiencing a number of SB EEPROM errors, both 1800 and
2500. 
It is easy enough to reset the inverter, but this can really be
inconvenient 
when it takes a full day to make a round trip to spend five minutes
restarting 
the system. SMA says that they still are working on a fix, and yet
apparently 
some installers have already received a new chip that will stop the
problem, 
supposedly.

I have noticed that the error has only (so far) occurred on multiple
inverter 
installs, and I have never had to reset the same inverter twice. 

Has anybody else been having this problem? Are there any ideas about
what is 
going on?

Patrick A. Redgate
AMECO
Long Beach, CA
(562) 595-9570
www.amecosolar.com 

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