@bart - I ignore the errors but you can parse for them as needed.

Here is the normal output with only the Status box checked (output from the Debug tab of Node-RED):

May 22, 2016 at 10:35:46 AM CDT debug(msg.payload)
msg.payload : Object
{ “status”: { “state”: true, “nowPower”: 240.75, “nowCurrent”: 2.0359, “day”: 0.029, “week”: 0.029, “month”: 10.878, “lastToggleTime”: “2016-04-20T02:59:31.000Z” } }

.
Here is the error output with SmartPlug unplugged:

May 22, 2016 at 10:39:38 AM CDT EdiPlug
msg : error
Error: Request timeout occurred - request aborted

May 22, 2016 at 10:39:53 AM CDT EdiPlug
msg : error
Error: Request timeout occurred - request aborted

May 22, 2016 at 10:40:08 AM CDT EdiPlug
msg : error
Error: Request timeout occurred - request aborted

In my test the above continues every 15 seconds (8 messages total) lasting about 2 minutes.
.

Here is the error output with SmartPlug unplugged longer than 2 minutes:

May 22, 2016 at 10:41:31 AM CDT EdiPlug
msg : error
Error: connect EHOSTUNREACH

May 22, 2016 at 10:41:39 AM CDT EdiPlug
msg : error
Error: connect EHOSTUNREACH

May 22, 2016 at 10:41:47 AM CDT EdiPlug
msg : error
Error: connect EHOSTUNREACH

The above continues every 8 seconds until the SmartPlug is plugged into an outlet.