[Nut-upsuser] Fw: Interfacing a Contact-Closure UPS to Mac OS X and Linux

[Charles Lepple]

On Aug 21, 2010, at 5:17 AM, Roger Salisbury wrote:

> Hi David
>
> As per the link
>
> http://www.llondel.org/ups.shtml

Not sure if David is on the list, but we can probably help.

> & the final testing paragraph.
>
> I have set up a Lantech UPS similiar to your write up for  your  
> Powersure Proactive and Powersure Personal  UPS's
>
> On LOW BATT
> it shuts down OK.

Do you get the "OB" ("on battery") status before "LB" ("low battery")?

> BUT as with other  many UPS's during the
> wait period from low batt to start of shutdown ... IE

In NUT, there is no wait period - when upsd sees the LB status from  
the driver, it starts the shutdown sequence.

The idea is that if an UPS says "low battery" (versus just "on  
battery") then it only has a few minutes left.

The other potential problem with allowing a return from the low  
battery state is that if the power returns for only a minute or two,  
and the UPS starts up, there will not be enough battery power to  
detect whether or not the computer should keep starting up or not.