Issue
A user wants to configure a static IP address on a SpaceLogic Twisted Pair Adapter (SXWTPAE10001). After installing the Twisted Pair Adapter Engineering Tool, no option is available to modify the adapter IP configuration or change it from DHCP to a fixed IP address.
Product Line
EcoStruxure Building Operation
Environment
- SpaceLogic Twisted Pair Adapter (SXWTPAE10001)
- Twisted Pair Adapter Engineering Tool
- Ethernet infrastructure over existing twisted-pair cabling
Cause
No mechanism is available to modify the adapter's maintenance IP address or configure the adapter for DHCP or a user-defined static IP address. The adapter uses a fixed maintenance IP address (192.168.0.249) for engineering access and operates as a Layer 2 Ethernet bridge/switch rather than a configurable Layer 3 network device, and this is the key reason why configurable IP addressing is not relevant to its normal operation.
Resolution
- Configuring the SXWTPAE10001 with a user-defined static IP address is not supported. The maintenance IP address (192.168.0.249) is fixed and intended only for engineering access through the Twisted Pair Adapter Engineering Tool.
- During normal operation, the adapter transparently forwards Layer 2 Ethernet traffic while connected devices retain their own operational IP addresses.
- If engineering access is required, configure a secondary IP address on the engineering workstation within the 192.168.0.x/24 subnet and connect using the Twisted Pair Adapter Engineering Tool as noted in the Twisted Pair Adapter Engineering Tool v1.0.0 Release Notes. This maintenance IP is not used for normal runtime communications.
How the Twisted Pair Adapter operates
The TPA is a Layer 2 device and it's role is simply to transport Ethernet frames across the existing twisted-pair infrastructure. From the perspective of the connected IP devices, the adapter is largely transparent. To put this into context:
-
- Layer 2 (Data Link Layer) works with Ethernet frames and MAC addresses.
- Layer 3 (Network Layer) works with IP addresses.
- Routers operate at Layer 3 and make forwarding decisions based on IP addresses.
- Switches and bridges operate at Layer 2 and make forwarding decisions based on MAC addresses.
A useful analogy is a standard Ethernet switch. When you connect an AS-P or RP-C to an Ethernet switch, the switch itself does not participate in the BACnet/IP communications. The switch simply learns which MAC addresses are connected to each port and forwards Ethernet frames accordingly. The BACnet/IP communication occurs through the switch, not with the switch.
The Twisted Pair Adapter performs a similar function. The AS-P, RP-C, and other IP devices retain their own operational IP addresses and communicate normally using BACnet/IP or BACnet/SC.
