WithBACnet COV feature, Weintek HMI can be used in any massive node BACnet system, without problem of communication data overflow. The COV function is a BACnet feature which allows each BACnet device/objects changed from passive server to active server. With this feature the HMI don’t have to constantly poll all the node one by one, the BACnet device will send out data when it is changed. The BACnet COV is as “Alarm and Event” in BACnet subnet system.
Applications:
- Building Automation
- HVAC system
- Security System
- Control Network
Example:
The previous EBPro BACnet driver only support the BACnet devices as passive server. If the system contains too many devices, constantly poll and respond data will cause the communication data overflow flow exceeded.
With the COV feature, Weintek HMI support the BACnet devices as active server. Therefore data transmission will only happen when: 1) HMI subscribes the command to the devices or 2) The devices renew the data, it will significantly reduce the communication flow.
What’s special about Weintek COV feature:
The COV feature can reduce the flow issue, however, if the system contains massive devices or objects. During the HMI subscribes or devices renew data, it may cause data overflow. It also provides a special mechanism to distribute data flow. The packet will be sent in sequence, instead of transferring all the data at the same time.
Example:
1. The HMI requests the data from devices (red line). Only three devices having data changed.
2. The blue line device will send the data back to HMI first.
3. After the first device send the data, the second device will send the data back (yellow line).
4. The last device send the data back (green line)
