IDEC MICRO/I HG4G-CJT22 F-B Series User Manual page 208

7 BACnet Communication
Unsubscribed COV (COVU) function
●
In the COVU (Change Of Value Unsubscribed) function, the MICRO/I spontaneously provides notification that
Present_Value or Status_Flags of a specific object has changed to all BACnet devices connected to the same network.
The properties of objects that correspond to the COVU function and the timing of when to provide notification of
changes are given as follows.
Object Properties
Analog Input
Present_Value
Analog Output
Status_Flags
Analog Value
Binary Input
Present_Value
Binary Output
Status_Flags
Binary Value
The MICRO/I implements the COVU function by sending the Unconfirmed COV Notification service to BACnet devices.
For example, when BACnet/IP is started with AI-10 (Analog Input object, instant number 10) having the status in the
following table, notification is provided on the status of the properties at the set cycle (Unsubscribed COV frequency).
Present_Value
COV_Increment
Status_Flags
BACnet
device (1)
• When using the COVU function, the values of properties can be regularly sent to BACnet devices,
regardless of any change in the value of the properties.
• The COVU function can be set for each object.
• Only one Unsubscribed COV Frequency can be set for the MICRO/I. Different frequencies cannot be set
for each object.
• If the Unsubscribed COV Frequency is set to 0, the COV function is stopped, and notification is provided
only when there is a change in the target property.
• When the Unsubscribed COV frequency is changed by a device address, the change will be applied after
the service is next initiated.
• Notification may not be provided for changes in values that are faster than the synchronization cycle of
objects and device addresses.
*1 Refer to "BACnet/IP Settings" on page 3-108.
3-102
Notification of the status is provided at the interval of the Unsubscribed COV frequency
Notification of change is also provided when (1) or (2) as follows.
When Present_Value has changed to a value greater than or equal to the value set
(1) for COV_Increment (starting point is from when the previous COV notification was
sent)
(2) When any of the bits in Status_Flags have changed
Notification of change is provided when (1) or (2) as follows.
(1) When
Present_Value
(2) When any of the bits in Status_Flags have changed
AI-10 Properties
BACnet
device (2)
Present_Value of AI-10 is 10.0.
Status_Flags is { }.
COV notification transmission
Present_Value of AI-10 is 10.0.
Status_Flags is { }.
COV notification transmission
Present_Value of AI-10 has changed to 15.
Status_Flags is {FAULT}.
COV notification transmission
Present_Value of AI-10 is 15.0.
Status_Flags is {FAULT}.
COV notification transmission
WindO/I-NV4 User's Manual
Timing to Provide Notification of Change
has changed
10.0
3.0
{ }
MICRO/I
Present_Value of AI-10: 10.0
Status_Flags: { }
Present_Value of AI-10: 15.0
Status_Flags: {FAULT}
Value
Unsubscribed COV frequency
*1
.