redPlc Software-PLC

redPlc Node-Red nodes for the realization of Software-PLC with Ladder-Logic according to IEC 61131-3.

• Download little tutorial using redPlc: automation_using_nodered.pdf

• Install redPlc Nodes:
  @redplc/node-red-redplc

• Install Module Nodes.
  Module Nodes exchange data with hardware or communication
  and updates the redPlc variables.
  Module Nodes also creates the I, Q, IA and QA variables.
  

Module Nodes not hardware based

Module-Node	Function
@redplc/node-red-time	Get System-Time or NTP-Time

Module Nodes for Raspberry Pi

Module-Node	Function
@redplc/node-red-rpi-gpio	GPIO digital input/output, pwm, counter with direct i/o
@redplc/node-red-redplc-gpiox	GPIO digital input/output using linux character device interface
@redplc/node-red-rpi-ads1115	ads1115 16bit analog to digital converter
@redplc/node-red-rpi-mcp3424	mcp3424 18bit analog to digital converter
@redplc/node-red-rpi-ds18b20	ds18b20 temperature sensor

Module Nodes for special hardware

Module-Node	Function
@redplc/node-red-wago-cc100-io	Wago CC100 Controller I/O

Example

In this example a tank is being filled or emptied.
The process is started with the START switch
and stopped with the STOP switch.
The filling level of the tank is determined using the LOW SWITCH and HIGH SWITCH.
When the IN VALVE is activated, the tank is filled.
When the OUT VALVE is activated, the tank is emptied.
The control automatically fills and empties the tank.

This is the original Ladder Logic:

https://www.sanfoundry.com/plc-program-control-level-single-tank/

Ladder Logic with Raspberry Pi

Node-Red flow file is in examples folder: Tank_Control_RaspberryPi.json

This is the pin assignment for Raspberry Pi:

GPIO Pin	Set	Variable	Function
GPIO21	Input/Pullup	I0.21	START
GPIO20	Input/Pullup	I0.20	STOP
GPIO16	Input/Pullup	I0.16	LOW SWITCH
GPIO12	Input/Pullup	I0.12	HIGH SWITCH
GPIO23	Output	Q0.23	OUT VALVE
GPIO24	Output	Q0.24	IN VALVE
		M0.0	MASTER

Note: All Raspberry Pi inputs are set to Pullup.
That's why the switches have to switch to ground.

Ladder Logic with Wago Controller CC100

Node-Red flow file is in examples folder: Tank_Control_cc100.json

This is the pin assignment for Wago Controller CC100:

Pin	Set	Variable	Function
DI1	Input	I0.0	START
DI2	Input	I0.1	STOP
DI3	Input	I0.2	LOW SWITCH
DI4	Input	I0.3	HIGH SWITCH
DO1	Output	Q0.0	OUT VALVE
DO2	Output	Q0.1	IN VALVE
		M0.0	MASTER