Non windows lan connection problem

my wd my cloud ex2 is supposed to live in a industrial network with a windows computer, a switch, and some industrial interfaces without dns and dhcp so no direct access to internet., but with a static ip adress, so the windows machine can use it for backup of program files and productions data. I have used wd cloud my home, before the new model without the possibility af static ip.
So set ex2 to a stictic ip adress sub but no dns and no dhcp, can not connect or ping ex2 with static ip. any idears ??
Best regards

If you set the subnet, that means that you ask it to use the gateway on that subnet, for any communication outside the subnet. You need to provide a default gateway for any IP device to communicate on a LAN. This is a prerequisite. The gateway handles the passing traffic. You CAN setup your PC to be the gateway, if it’s on the same subnet. Alternatively, all of your devices needs to be on the same subnet… Are they ? Normally the default private range is 192.168.x.x, not 198.168.x.x as you write. What does the PC respond to ?