The project presented here provides an isolated interface between the RS-232 cable network and the connected UART systems to protect against voltage spikes and ground loops within the noisy environment and improve system reliability. The project achieves a robust data communication link in harsh industrial environment. ADM3251E chip from Analog Devices is the heart of the project, this chip is a high speed, 2.5KV fully isolated, single-channel RS-232 transceiver device that operates from a single 5 V power supply. Due to the high ESD protection on the RIN and TOUT pins, the device is ideally suited for operation in electrically harsh environments or where RS-232 cables are frequently being plugged and unplugged. Four external 0.1 μF charge pump capacitors are used for the voltage doubler/inverter, permitting operation from a single 5 V supply. Project operates at data rates up to 460kbps. RS-232 transceiver D-Sub 9 Pin Female block provide convenient signal connections. D2 Power LEDs on respective isolation ends. The chip has inbuilt isolated DC-DC Converter thus the project can work with single supply. Apply 5V DC to CN2 and project is ready to go.
- Supply 5V DC CN2 Single Supply Operations
- CN4 RS232 Aux
- 9 Pin D-Type Female Connector for RS232 Interface (CN1)
- 5 Pin Male Header Connector for UART Interface (CN2)
- 5KV Fully isolation
- Data Rates Up to 460kbps
- PCB DIMENSIONS: 35.88 x 31.91mm
5.0 V LOGIC TO TIA-232E TRANSMITTER
The transmitter driver converts the 5.0 V logic input levels into RS-232 output levels. When driving an RS-232 load with VCC = 5.0 V, the output voltage swing is typically ±10 V.
TIA-232E TO 5 V LOGIC RECEIVER
The receiver is an inverting level-shifter that accepts the RS-232 input level and translates it into a 5.0 V logic output level. The input has an internal 5 kΩ pull-down resistor to ground and is also protected against overvoltage of up to ±30 V. An unconnected input is pulled to 0 V by the internal 5 kΩ pull-down resistor. This, therefore, results in a Logic 1 output level for an unconnected input or for an input connected to GND. The receiver has a Schmitt-trigger input with a hysteresis level of 0.1 V. This ensures error-free reception for both a noisy input and for an input with slow transition times.