Operation
19
4 Operation
4.1 Node Object
Node
Object #0
Node
Management
Network
Variables
Configuration
Variables
nviRequest
SNVT_obj_request
nv1
nviTimeSet
SNVT_time_stamp
nv3
nvoStatus
SNVT_obj_status
nv2
nvoAlarm
SNVT_alarm
nv4
nciMaxStsSendT SNVT_elapsed_tm
nc22
Figure 4.1: Node Object
The Node object in the WattNode provides status and request mechanisms, time of day, and alarms. The
WattNode uses several floating point network variables. Instead of the scientific notation for floating point
numbers (1.23×10
3
= 1230), we will use the standard computer notation (1.23e3).
4.1.1 Requests
The request variable
nviRequest
is used to request information from or to change the state of any of the
objects. The request contains the number of the object to which the request is directed and the request type.
In response to each request, the object’s status is returned in
nvoStatus
. The status variable
nvoStatus
also
indicates if the request was made of an invalid object number, or if the object doesn’t support the request
made of it.
The
nviRequest
variable can zero values that may be used for billing. To prevent unauthorized tampering,
authentication should be enabled for
nviRequest
. The NORMAL request will only zero energy or peak
demand if the demand object was disabled when the NORMAL request was received.
Whenever energy is zeroed, the time stamp
nvoEngyClrT
will be set to the current time. Whenever peak
demand is reset, the time stamp
nvoPkDemResetT
will be set to the current time. If demand is disabled and
then enabled,
nvoPkDemResetT
will be set to the current time.
The following table shows the requests and effects for each object.
