Registrieren

I'm a relative newbie, so apologies in advance if I'm framing a stupid question. I am saving a numeric value captured from a dashboard slider as flow.low - and a debug node shows it saved (as expected) with a numeric value of 5. In a subsequent node setup for testing purposes, I simply set msg.payload to flow.low and attach a debug node. The debug node shows the value as "undefined". What am I doing wrong? The relevant nodes are as follows, first for setting the value in a "change" node ... ...