The new powerline modem
The current highdatarate master modem reached the end of its life as
multiple parts were called obsolete by their respective manufacturers,
plus maintaining the software became ever harder. So upon sufficient
demand I'll consider to design a new version.
the new concept
We learnt a lot over the past 15 years, so some changes are due.
The current firmware is far too complex and it appears as black box.
Some hardware requirements changed over the years.
- the supply is 24V AC as before.
- a fast bidirectional, full duplex bus, such as the RS422 connects
to the PC. There is galvanic separation of the bus in the HCCU.
The current model has just RS232.
- Coupling to the powerline is done with an exchangeable transformer
plus the usual caps. Additionally, there will be fuses to the
overvoltage protection.
- Since multiple tapping points became the rule, sockets for several
relais will be provided such that a switchbox can be included.
These relais will be under software control.
- The automatic functionality included in the current version will
be removed. This functionality created a lot of problems as it
appeared as blackbox for the developper.
Therefore it will have to be remodelled in the PC. Guidance will be
provided plus the maintenance of the code on the PC is simpler.
- Control information to be sent on the bus requires the protocol
to be tweaked to accomodate for it.
- The firmware is accessible to the developper. Actually the developper
is invited to take part in the development process of the firmware
itself. Therefore no license fees are due.
- The firmware should be downloadable through the RS422 bus.
- looking at a rather low number of produced units, the micro controller
is to be choosen to simplify development and debugging at the expense
of a higher unit price of the microcontroller. Meaning a 8032 is not the
right one.
- also due to the low numbers, the case will be a standard case, a custom
case appears to be too expensive. In order to pass the EMC rules, a
metal case is preferred.
timetable of this project
- collecting specifications
- design hardware
- build testing/debugging context
- functional test
- write basic firmware
- reality testing
- emc test + whatever other tests
- write extended firmware
Without defined specifications, I'd estimate the required time for
steps 2-6 in the region of 3 to 4 month.
costs of this project
- Development of the hardware according to the specifications
is in the order of 15'000 Euro
- Development of the debugging context plus the firmware is
in the order of 15'000 Euro
- Testing according to the emc rules is in the order of 2000Euro
These numbers may be a bit low and may be revised in the specification
stage.
the final hccu
it is likely much smaller than the current one and also much cheaper.
Production cost should be in the range of 300-400Euro @ 10.
start of this project
Upon sufficient demand and/or covered cost I may consider starting
with this project.
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last updated: 12.nov.03, or perhaps later
Copyright (99,2003) Ing.Büro R.Tschaggelar