A 4 inputs 4 outputs PLC board based on Arduino micro pro (or clone) to drive a 4 Way relay board and made to run with open_PLC
work in progress...
Micro pro PLC is a small Programable Logic Controlor board based on Arduino micro pro (ATmega32U4 microcontroler). It is designed for small systems with 4 digital inputs, 4 digital outputs, 2 analog inputs and a Modbus/RS485 access. It is designed to fit on easy available 4 way relay board
I first designed it for use with open_PLC but it can be use with Arduino IDE or any other way you want to devellop the software you put on the controler
| Board pin | Arduino pin |
|---|---|
| I0.0 | D2 |
| I0.1 | D3 |
| I0.2 | D4 |
| I0.3 | D5 |
| Output0 | D7 |
| Output1 | D8 |
| Output2 | D14 |
| Output3 | D15 |
| IW0.0 | A0 |
| IW0.1 | A1 |
- Modbus/RS485 drived by D1 for Tx and D0 for RX (Serial1)
- RS485 is enabled by D6
- Outputs open drain - 200mA drain output
- Input actived by pooling to GND (need to drain ~20mA)
PDF version available here
| Reference | Value | Footprint |
|---|---|---|
| C1,C2,C3 | 100nF | SMD 0805 |
| D1,D2,D3,D4 | LED_3mm | |
| J1 | 01x06_Pin | PinSocket_2.54mm |
| J2,J3,J4 | TerminalBlock_Phoenix_MKDS 5.00mm | |
| J5 | 01x02_Pin | PinHeader_2.54mm |
| J6,J7 | 01x04_Pin | PinHeader_2.54mm or JST HX |
| Q1,Q2,Q3,Q4 | 2N7002K | SOT-23 |
| R1,R2,R3,R4 | 10k | SMD 0805 |
| R5,R6,R7,R8 | 4k7 | SMD 0805 |
| R9 | 120 | SMD 0805 |
| R10,R11,R12,R13 | 100 | SMD 0805 |
| R14,R15 | 20k | SMD 0805 |
| U1 | Sparkfun_Pro_Micro or Clone | |
| U2,U3,U4,U5 | PC817 | DIP4 |
| U6 | MAX485E | DIP8 |
also available here