Errors
The following errors are returned as second argument if something went wrong:
'Control command syntax error' -- http status 400 'Invalid username or password' -- http status 401 'Read only' -- http status 403 'Internal server error' -- http status 500 'Metering are only available on NETIO Model "NETIO 4All". Your model is: $modulename' -- if measure_info() function is used on model other then NETIO 4All