In node-red the msg object is how you pass the values from one node to the next. Your pac read node gets the value, then the “blocks” or nodes after that are what process your values contained in the msg.
Are you using a debug block after your node-red read blog? (it’ll output the msg object / msg.payload to the debug panel on the right so you can see what value you’re pulling out.) If you are using that and you’re not seeing any output or error messages the next question would be if the flow is enabled and live.
Also something to check is I am pretty sure it is only the PAC that responds to the rest API calls, it sounds like the EB2 is set up as a module from the PAC, make sure you’ve set node-red to talk to the PAC not the EB2. (You should be able to access the tag since the EB2 is a module in the PAC.)