What does digital input mean? Is this a dry input contact or are you to supply a voltage input?
Electronics engineer for 50 years. “Digital input” is a rather poor term to use.
I am using mine as a dry contact as this is the simplest way.
More details, as ever, are in the manual.
Yes the manual section 16 implies a 3 volt level is on the positive terminal when connected to the lower terminal it will cause an ON state. " dry input contacts only" would be better wording to avoid damage.
“Digital input” implies, from my knowledge, an input level not greater than 3.3V or 5V, depending on system.
Possible pull-up on the pin and this can be confirmed if, when measuring the pin, you’ll get 3.3V or 5V, this solving the voltage “mystery” also.
Of course, only 0V and 3.3V(5V) will be considered correct levels.
Here’s a schematic from Victron archives for their hardware:
Thank you for the archive drawing. The point is the user should not introduce a voltage supply(3.3V or 5V) from another source.
Doesn’t matter if one introduces an additional voltage supply… The 22K resistors will limit anything excessive.
You can even have 0-12V levels, the 22K resistors together with the schottky barrier diodes will do their job.
As for the 3V3 rail “leak”, a max of 6mA (12V/(10K/5)) “pull-up” will also be no problem…
I agree the barrier diodes in a perfect world should work but I do trust more in optical isolator like Actisense USG-2 where each side of the isolator is powered independently with isolated grounds.
All issues resolved. You must change the I/O logic to have a normally open contact OK and a closed contact as ALARM.
One issue that needs to be resolved is to be able to clear alarm and event logs. Does any one know how to do this? Thank you