How does the ATS function work on this 24v LF inverter?

How does the ATS function work on this 24v LF inverter?

ATS Function on 24v LF inverter:

a. when switch to ATS function, then: 

for 24v system, your battery voltage when 21.5v, will auto switch to ATS mode, means inverter will auto switch the home power to provide the 220v AC output & charge your 

battery at the same time. After charge your battery to 28v,  will be back to inverter mode.(PS.AC input cable need plug in all the time)

b.if you are using solar system, then you need stay at ATS function , because in the day time, all the power come from solar, after night time or battery under 21.5V,  will auto 

switch to home power, will let your electric products keep working, until day the sun come on again, then will be back to inverter mode again.