I am using Ignition to connect to a few ML1000’s that use ENI modules without issue. These 1000’s are also connected to Wonderware through RSLinx and OPCLinx.
Mine never have a problem connecting and always resolve to “Connected” in the gateway. I’d check your network connectivity to the 1500 via a ping from the gateway first and work from there. Also look at the ENI webpage to see how many total connections are already in use.
Shawn