Can ping PLC ip, but cant connect

[h1rik_fryd]

Hello guys, 

Im having trouble connecting to my PLC via Ethernet. When I ping my PLC IP address (169.254.1.100) in cmd I get replys every time, but when I try to connect to the PLC  in Unilogic, this IP doesnt work. I have my computer IP set to 169.254.1.121, subnet to 255.255.255.0. The IP in the PLC panel is set to 169.254.1.100, subnet is 255.255.255.0. The IP in the PLC CPU is set to 169.254.1.99, subnet is 255.255.255.0. 

Could the reason for the problem be differences in software maybe? Or is it something else Im missing?

[Saragani]

PLC Version, UniLogic Version, is this PLC new or it used to have an older firmware version and then it was updated? Did it used to work but now it doesn't? (If it so, why did it stop communicating).

Did you give the PLC the IP: 169.254.100.1? (Is it by a project that was downloaded to it, or by configuring the IP in the UniApps?)

[Ausman]

I know it depends on how you are connecting, but is all of this correct and not missing needed info?

[dierkens]

Personally I wouldn't use this subnet for anything of interest on my networks.

Here's why.

169.254.0.0/16 (169.254.0.0 – 169.254.255.255)

These addresses are “link local,” which means packets with these addresses are sent out to the network, but should never be forwarded to other parts of the network. You’ll often see addresses from this range if a device is unable to get an address using DHCP. Then it simply takes an address from this range and uses it to try to at least communicate locally.

Any local device that can't get to the DHCP could, simply by chance, get assigned in this subnet and that could be what you're pinging.