Table of Contents
Serial ports (RS-485)
Port mapping
The tables below provide information on what RS-485 serial ports are available and how they are mapped into Linux ports.
Ports within /run/unipi-plc/by-sys/:
| type | S1-RS485 | S2-RS485 |
|---|---|---|
| E410 | rs485.1/tty | rs485.2/tty |
| E411 | rs485.1/tty | - |
| E412 | rs485.1/tty | rs485.2/tty |
| E413 | rs485.1/tty | rs485.2/tty |
Ports within /dev/:
| type | S1-RS485 | S2-RS485 |
|---|---|---|
| E410 | ttyAMA1 | ttyAMA2 |
| E411 | ttyAMA1 | - |
| E412 | ttyAMA1 | ttyAMA2 |
| E413 | ttyAMA1 | ttyAMA2 |
Technical parameters
| RS-485 Terminals | SxA, SxB | |
| Negative connection (D-) | A | |
| Positive connection (D+) | B | |
| Galvanic isolation | Yes, see illustration below (Functional, cannot exceed SELV) | |
| ESD protection | ±15 kV | |
| Communication speeds | 50 baud 150 baud 300 baud 600 baud 1 200 baud 2 400 baud 4 800 baud 9 600 baud 19 200 baud 38 400 baud 57 600 baud 115 200 baud | 230 400 baud 460 800 baud 500 000 baud 576 000 baud 921 600 baud 1 000 000 baud 1 152 000 baud 1 500 000 baud 2 000 000 baud 2 500 000 baud 3 000 000 baud |
| Input impedance | approx. 1.2 kΩ | |
| Input voltage hysteresis | 30 mV | |
| Output characteristic | ±2.3 V | |
| Terminating resistor | Built-in attachable 120 Ω (S-END) |
|
| RS-485 pull-up / pull-down resistors | 560 Ω / 560 Ω | |
Internal isolation of RS-485
