What is it?

EV331_TTL is a slave evaluation board of transparent transmission UART signal from master, connecting UART interface of MCU in slave station, or connecting computer by UART to USB, which is tested transmitting and receiving signal via MODBUS or others. The board can power supply up to 1A output, and DC/DC suitable voltage to slave device, also can be tested with dummy load.

EV331_485 is a slave evaluation board, modulate and demodulate UART signal to RS-485 and power supply to slave station meanwhile. The end-user can take the use of this board directly testing their devices with RS-485 interface via MODBUS, no necessary to change or update the software.

Why did you make it?

We all knew RS-485 is a differential signal standard. Traditional RS-485 systems use at least four wires to simultaneously transmit signals and power: two wires for differential RS-485 signals, and two wires for power and ground. The weight and cost of these long cables increase system complexity and installation costs. Due to the use of multiple wires, there is a risk of system failure if the connection is incorrect, which further increases the complexity of the system.

Fortunately, when designing the RS-485 interface, the four-wire solution is no longer the only option. POWERBUS can fulfill power line communication, and ultimately reduce the number of wires from 4 to 2, while improving system performance and reducing total cost. and Powerbus is non-polarized 2-wire system, it has no polarity A.B without mis-connecting. It's topology is free, it supports tree, star, daisy-chain, mesh etc. it supports any cable style, no need match end line resistors.

What makes it special?

Compared with RS-485, Powerbus has some significant advantages such as :

A) It utilizes 2 core cables for both power and communication. This minimizes the number of cable cores and ultimately cutting down on the cost of install

B) Cable cores on 2-wire systems have no polarity. This both minimizes the possibility of mis-connection and speeds up the install time. RS-485 has polarity A.B, mis-connection will damage all of the devices on bus

C) Arbitrary topology, it supports star, tree, daisy-chain and Mesh etc. (RS-485 topology is daisy-chain only)

D) Up to 9600 Baud in Half Duplex for UART Protocol, compatible with RS-485, transparent interfaces.

E) It allows up to 256 nodes on BUS and more with repeater. Up to 3km length of communication. Supports 12v-48vDC input and output maximum 20A in bus and 1A in each slave node. (powerbus supports max 960w)