Control Network Newsletter
EIA-485 Terminator Provides Fail-Safe Biasing for BACnet MS/TP and Modbus RTU Networks
The 485-TER is a standalone active terminator that is used on popular EIA-485 networks such as Modbus RTU and BACnet MS/TP providing sufficient termination and biasing for stable operation. Fail-safe bias ensures that an un-driven line assumes a defined state. When a head-end device does not have internal bias and termination two 485-TER devices should be installed - one at each end of the network. This will provide stability and error free communication. The 485-TER can be used with either 2-wire non-isolated EIA-485 networks or 3-wire isolated EIA-485 networks.
The 485-TER is a compact device that can be applied in the field quickly and easily. It comes with an isolated cover allowing it to be installed most anywhere. The 485-TER can be installed to stabilize the physical layer of an EIA-485 network by providing the proper voltage bias (greater than 200mV) and termination (120 Ohms) to the network. The 485-TER requires 24VAC +/-10% 1VA or 20-30VDC .5W power. Power can be shared with the same power source used by the controller.
Visit our accessories page to purchase the active EIA-485 terminator (5 Pieces).