J
Joerg
- Jan 1, 1970
- 0
Hello Stanislaw,
Yep, been designing med stuff since the mid 80's. We kept it under 10uA
because you have to go with the "least common denominator" between
countries' regs. Reason I mentioned it is because it does help with
CMRR, big time.
After a while you get a good feel which parts you can use and which
companies are the most supportive in obtaining the docs for the design
history file and ECO. The problem is insulated wire for magnetics since
it needs to be tested and certified per running foot. Every once in a
while a supplier drops away and clearing a new one requires quite some time.
As to no excuses, I go one step farther than IEC601 goes (or used to
go). Even for stuff that doesn't have to be defibrillator proof I insist
on designing it that way. Else I would turn down the project. Even more
so after seeing how over-worked and tired physicians can be. That's when
even the most robust person can make mistakes.
Nothing to do with measuring the signal and CMRR. Safety = 50 uA (
that's my keyboard spelling micro) at line frequency can (does NOT have
to ) throw the heart into pachanga dance (medically called fibrillation).
Yep, been designing med stuff since the mid 80's. We kept it under 10uA
because you have to go with the "least common denominator" between
countries' regs. Reason I mentioned it is because it does help with
CMRR, big time.
This part of medical electronics many times IS the major time consuming
part of designing an intensive care room equipment.
There are NO excuses.
After a while you get a good feel which parts you can use and which
companies are the most supportive in obtaining the docs for the design
history file and ECO. The problem is insulated wire for magnetics since
it needs to be tested and certified per running foot. Every once in a
while a supplier drops away and clearing a new one requires quite some time.
As to no excuses, I go one step farther than IEC601 goes (or used to
go). Even for stuff that doesn't have to be defibrillator proof I insist
on designing it that way. Else I would turn down the project. Even more
so after seeing how over-worked and tired physicians can be. That's when
even the most robust person can make mistakes.