relay
Hello,
have this relay board, how can i connect this board to a printer port (LPT1) and can this port cope with the amps needed to drive the board?
I am not an electrician, so please take notice of this fact in your answer.
This relay is needed to switch a router motor on and off, the signal is send from "Mach3" (Milling software) through the printer port (LPT1).
The motor is 1050w 5a 230v AC.
Obvious problems: Well yes. As drawn right now, there is some confusion but:
1: Either you don't get 220V to your secondary relay (The one connected to the Arduino) because the line leaving your primary relay going left is a trigger signal line, rather than a power line OR
2: You DO get 220V to your secondary relay and you cannot trigger your first relay because the line leaving your primary relay going left is a power line, rather than a trigger signal line.
My first recommendation would be to redraw your diagram with clear labels on all wires.
Make sure diodes can handle motor startup current. Measure current to motor on startup. Add safety factor. You should know the drill.
simulate this circuit – Schematic created using CircuitLab
Insert this into either black or white wire going to the motor.
Not sure of polarities on diodes. You have to figure up/down and appropriate diode polarity.
Do this one limit switch and diode at a time. Switch stops motor at limit and diode allows reversing of motor.
Normally Upper and Lower are closed, but at limits one will open and shuts off motor. Diode will be reversed biased.
Diode will allow motor to go in reverse direction. Once motor moves, limit switch closes and power flows through switches.
Once limit switches are closed, motor can go in either direction until limit switches are opened.
Best Answer
PC parallel port pinout.
simulate this circuit – Schematic created using CircuitLab
Setup
Good assembly practice
How it works
Mach3 will pull the port output pin low causing current to flow through D1 and D2 lighting them both up. D1 is half of an optocoupler and it turns on transistor Q1 allowing some current to pass through. This turns on Q2 allowing current to pass from the +5, through the relay and through Q2 to the negative. This energises the relay. Relays are notorious for giving a high-voltage kick from the coil when switched off. This puts Q2 in danger. D3 prevents the high-voltage kick and protects the transistor.
Note that the two GND terminals are connected.