@svicar 

Can I make guest wifi on EAP110 that will not see the other devices that will be connected to private wifi?

 

Yes, you can. EAP110 V4 supports Guest Network function, here is the guide about how to configure Guest Network for your reference.

https://www.tp-link.com/support/faq/1060/

What about wireless controler? Can I install it on my laptop only for configuration and then turn it off? Or it must be on all the time?

 

TP-Link provides Omada Controller software for free, but it only supports Windows OS or Linux.

https://www.tp-link.com/support/download/eap110/#Controller_Software

Some advanced features will require the Controller to keep running all the time, you can read the FAQ below to get more details.

https://www.tp-link.com/support/faq/2051/

Can I put all EAP110 private network on the same SSID? what about channal? it must be the same or diferent? 

Surely you can. It's suggested to set the APs with different channels to avoid wireless interference. Channel 1/6/11 is recommended for 2.4GHz.

P.S. The EAP110 is equipped with 100Mbps Ethernet port, and it only supports 2.4GHz. If you get more than 100Mbps bandwidth from your ISP, or you would like 5GHz WiFi, you may consider Gigabit devices instead, like EAP225.

Learn more about the product before the purchase from the official website.

https://www.tp-link.com/en/business-networking/ceiling-mount-ap/eap110/

@svicar 

Now I see that on EAP110 is written "end of life". What this mean? It is better to take EAP115 which is not "end of life"? Is any difference betwen EAP110 and EAP115 (I see the diference only in power suply)

 

It means EAP110 is discontinued in your region. If you prefer a 2.4GHz AP, EAP115 is your alternative.

And you are correct, the difference is only in power supply, EAP115 supports standard 802.3af PoE and DC power, while EAP110 only supports Passive PoE.