Issue
In SpaceLogic BACnet/IP controllers, a DHCP configuration takes longer than a Static IP configuration to start BACnet communications after a power cycle or restart.
Product Line
EcoStruxure Building Operation
Environment
- Building Operation Multi-purpose Controller (MP-C)
- Building Operation Multi-purpose VAV (MP-V)
- Building Operation Room Controller (RP-C)
- Building Operation Room VAV (RP-V)
Cause
The DHCP IP address assignment flow diagram is depicted in this WebHelp article: IP Address Settings for IP Communications. As a part of the failover process, once the controller receives a DHCP lease, it will send multiple ARP requests to ensure the IP address is not being used by another device, further delaying BACnet communications. If it does not detect another device using that IP, it will use the IP it was given to lease.
Also, SpaceLogic BACnet/IP controllers store the IP address and port of the controllers for which they have External Binds (Consumers/Producers). If a device is unavailable at that IP address because the DHCP lease has changed, the controller will have to use WHO-IS to find the new address of that controller.
Resolution
Configure the SpaceLogic BACnet/IP controller with a Static IP address, so the controller will boot directly using a Static IP address and start communicating via BACnet/IP. If on the AS-P Secondary Network with 10.110.210.0/24 network where AS-P DHCP server leases IP addresses from 2 and goes higher, assign static IP in a higher number range (0-254) for the last octet.
