Forum Members section DIY Ferduino controller Module operation of Relays-2 and PCF8575

Module operation of Relays-2 and PCF8575

Ask here about your controller made with pieces purchased in other shops.

Post Number:#1 Post Wed Nov 07, 2018 11:29 am
Posts: 38
Topics: 13
Images: 26
Solve rating: 0
Joined: Fri Jun 16, 2017 6:23 am
Topics: 13
Age: 57
Gender: None specified
National Flag:
Spain
I do not understand what happens to me with the relay module-2 controlled by the PCF8575.

I think I have a correct connection and in fact the relay LED lights up if I program any timer or when I activate the pumps or the feeder, but the relays do not work.

For example, if I connect a bulb with timer-1 (pin P5) and program it from 20:00 to 20:15, the relay LED flashes during the interval but the bulb is always on.

It does not occur to me that I am doing wrong.

Greetings and thanks

Post Number:#2 Post Thu Nov 08, 2018 4:27 pm
Posts: 38
Topics: 13
Images: 26
Solve rating: 0
Joined: Fri Jun 16, 2017 6:23 am
Topics: 13
Age: 57
Gender: None specified
National Flag:
Spain
The connection scheme that I have swiped is the following:

Image

As I was saying, the relay control LEDs (D1 ... D16) flash if, for example, I use a timer ...

Post Number:#3 Post Thu Nov 08, 2018 6:48 pm
Posts: 1591
Topics: 38
Images: 271
Solve rating: 216
Joined: Mon Mar 03, 2014 5:59 pm
Topics: 38
Age: 35
Location: São Paulo
Gender: Male
National Flag:
Brazil

Hi!

As I told here 5V pin in this relay board is an output.

Check the wiring on video.

Best regards.
Please do not PM me for support unless it is absolutely necessary.

I'll not write custom function to nobody unless you can pay for my job.

Post Number:#4 Post Thu Nov 08, 2018 8:19 pm
Posts: 38
Topics: 13
Images: 26
Solve rating: 0
Joined: Fri Jun 16, 2017 6:23 am
Topics: 13
Age: 57
Gender: None specified
National Flag:
Spain
I have disconnected the 5v and GND from the relay board and I have left the 12v and the GND in the corresponding connectors and the result is the same, the led of the board responds (flashes) but can not activate the relay. I have checked that the 12v arrive at the relay plate.

Post Number:#5 Post Thu Nov 08, 2018 8:26 pm
Posts: 1591
Topics: 38
Images: 271
Solve rating: 216
Joined: Mon Mar 03, 2014 5:59 pm
Topics: 38
Age: 35
Location: São Paulo
Gender: Male
National Flag:
Brazil

If your relay board is like this picture it should work with 5 V and not 12 V. Check the silk screen on relay. This model haven't a LM2576S to drop the voltage to 5 V.

So you should connect 5 V power supply to terminal block. Maybe your relays were damaged by 12 V power supply.
Please do not PM me for support unless it is absolutely necessary.

I'll not write custom function to nobody unless you can pay for my job.

Post Number:#6 Post Fri Nov 09, 2018 5:26 am
Posts: 38
Topics: 13
Images: 26
Solve rating: 0
Joined: Fri Jun 16, 2017 6:23 am
Topics: 13
Age: 57
Gender: None specified
National Flag:
Spain
The photo is from the internet of a relay board like mine but 5v instead of 12v.

I have tried with another plate that I have 5v and in this case neither light the LEDs.

With the 12v LEDs are lit, intermittently, but the relay is not activated.

I have no idea what may be due.

Post Number:#7 Post Fri Nov 09, 2018 8:47 am
Posts: 1591
Topics: 38
Images: 271
Solve rating: 216
Joined: Mon Mar 03, 2014 5:59 pm
Topics: 38
Age: 35
Location: São Paulo
Gender: Male
National Flag:
Brazil

Disconnect wires from PCF and try join D1 to GND to see if relay is activated.

Maybe your relays are not active LOW.
Please do not PM me for support unless it is absolutely necessary.

I'll not write custom function to nobody unless you can pay for my job.

Post Number:#8 Post Sat Nov 10, 2018 5:09 am
Posts: 38
Topics: 13
Images: 26
Solve rating: 0
Joined: Fri Jun 16, 2017 6:23 am
Topics: 13
Age: 57
Gender: None specified
National Flag:
Spain
In the relay module figure screenprinted Low Level Trigger.

And excuse my ignorance, but I do not understand very well how to perform the test you tell me. Could you clarify it?

Thank you

Post Number:#9 Post Sat Nov 10, 2018 8:46 am
Posts: 1591
Topics: 38
Images: 271
Solve rating: 216
Joined: Mon Mar 03, 2014 5:59 pm
Topics: 38
Age: 35
Location: São Paulo
Gender: Male
National Flag:
Brazil

Just connect the control pin (D1 - D16) to GND and it should turn on the relay.
Please do not PM me for support unless it is absolutely necessary.

I'll not write custom function to nobody unless you can pay for my job.

Post Number:#10 Post Sun Nov 11, 2018 5:21 am
Posts: 38
Topics: 13
Images: 26
Solve rating: 0
Joined: Fri Jun 16, 2017 6:23 am
Topics: 13
Age: 57
Gender: None specified
National Flag:
Spain
Yes, in this way the relay is activated. But if I connect it to the pin of the relay module, only the led is turned on but the relay is not activated

Post Number:#11 Post Sun Nov 11, 2018 9:49 am
Posts: 1591
Topics: 38
Images: 271
Solve rating: 216
Joined: Mon Mar 03, 2014 5:59 pm
Topics: 38
Age: 35
Location: São Paulo
Gender: Male
National Flag:
Brazil

The GND from 12 V power supply is connected to Arduino GND?

Are you using an ULN between PCF and relay board?
Please do not PM me for support unless it is absolutely necessary.

I'll not write custom function to nobody unless you can pay for my job.

Post Number:#12 Post Mon Nov 12, 2018 6:31 am
Posts: 38
Topics: 13
Images: 26
Solve rating: 0
Joined: Fri Jun 16, 2017 6:23 am
Topics: 13
Age: 57
Gender: None specified
National Flag:
Spain
I feed my controller through a 192W, 12V and 16A power supply.

From the power supply and by means of a steepdown to 7.5v directly Arduino food, by means of another steepdown I give 5v to the clock, sensors, relay module-1, ... and directly 12v to feed the dossing pumps, the surface fans and the power that I carry through the DB25 to the relay module. All the GND are joined in the base PCB that I have built and everything works correctly except the relay module-2 that if it has 12V of voltage measured at the terminals but the only thing I get is that the LEDs are illuminated but not activated the relays.

Image


On the other hand I confirm that I use a PCF8575 with two ULN2803A.

Regards,

Post Number:#13 Post Mon Nov 12, 2018 11:04 am
Posts: 1591
Topics: 38
Images: 271
Solve rating: 216
Joined: Mon Mar 03, 2014 5:59 pm
Topics: 38
Age: 35
Location: São Paulo
Gender: Male
National Flag:
Brazil

Can you hear a "click" when the LED is turned on?

Can you measure the continuity between common and NO terminal block?

P.S.: Don't forget to disconnect AC power on relay.
Please do not PM me for support unless it is absolutely necessary.

I'll not write custom function to nobody unless you can pay for my job.

Post Number:#14 Post Mon Nov 12, 2018 3:59 pm
Posts: 38
Topics: 13
Images: 26
Solve rating: 0
Joined: Fri Jun 16, 2017 6:23 am
Topics: 13
Age: 57
Gender: None specified
National Flag:
Spain
No, it does not make the typical activation "click", only the led lights up for about 5 seconds, it flashes, it lights up again and so for the whole time, for example, if a timer was programmed.

It only has continuity between common and NC.

Post Number:#15 Post Mon Nov 12, 2018 4:17 pm
Posts: 1591
Topics: 38
Images: 271
Solve rating: 216
Joined: Mon Mar 03, 2014 5:59 pm
Topics: 38
Age: 35
Location: São Paulo
Gender: Male
National Flag:
Brazil

It's very strange!

Maybe there's some problem with ULN.

What's the result with this code?

#include <Wire.h>
#include "PCF8575.h"

byte address = 0x20;

PCF8575 PCF8575;

void setup()
{
  Serial.begin(38400);
  Serial.println("I'm alive!");

  PCF8575.begin(address);

  for(int i = 0; i < 16; i++)
  {
    PCF8575.pinMode(i,OUTPUT);
  }
}

void loop()
{
  for(int i = 0; i < 16; i++)
  {
    PCF8575.digitalWrite(i, HIGH); // Tun on all pins
    delay(200);
  }
  delay(5000);
 
  for(int i = 0; i < 16; i++)
  {
    PCF8575.digitalWrite(i, LOW); // Turn off all pins
    delay(200);
  }
  delay(5000);
}
Please do not PM me for support unless it is absolutely necessary.

I'll not write custom function to nobody unless you can pay for my job.

Post Number:#16 Post Tue Nov 13, 2018 4:31 am
Posts: 38
Topics: 13
Images: 26
Solve rating: 0
Joined: Fri Jun 16, 2017 6:23 am
Topics: 13
Age: 57
Gender: None specified
National Flag:
Spain
It is the same, all LEDs turn on in sequence but the "click" does not occur. I am going to buy new ULN, I will change them and I will comment what happens.

Thank you !!

Post Number:#17 Post Tue Nov 13, 2018 9:34 am
Posts: 1591
Topics: 38
Images: 271
Solve rating: 216
Joined: Mon Mar 03, 2014 5:59 pm
Topics: 38
Age: 35
Location: São Paulo
Gender: Male
National Flag:
Brazil

I can see in this picture green and white wires connected to 5V pin. You can't connect 5 V from Arduino to 5V from relay board.

Also check if has continuity between GND pin and GND on terminal block in relay board. Otherwise connect it together.
Please do not PM me for support unless it is absolutely necessary.

I'll not write custom function to nobody unless you can pay for my job.

Post Number:#18 Post Thu Dec 20, 2018 4:31 pm
Posts: 38
Topics: 13
Images: 26
Solve rating: 0
Joined: Fri Jun 16, 2017 6:23 am
Topics: 13
Age: 57
Gender: None specified
National Flag:
Spain
Circuit PCF8575

I'm sorry to insist again but I still do not work the relay module and I think the problem may be in the design of the circuit. Can you check it and confirm if it is correct?

The power is through an external power supply of 12V and through a steepdown I take the 5V.

Thank you

Image

Post Number:#19 Post Fri Dec 21, 2018 7:35 pm
Posts: 1591
Topics: 38
Images: 271
Solve rating: 216
Joined: Mon Mar 03, 2014 5:59 pm
Topics: 38
Age: 35
Location: São Paulo
Gender: Male
National Flag:
Brazil

Hi!

The circuit seems ok to me.

When the PCF signal is HIGH what's the voltage in P0?

Best regards.
Please do not PM me for support unless it is absolutely necessary.

I'll not write custom function to nobody unless you can pay for my job.

Post Number:#20 Post Thu Apr 11, 2019 2:56 pm
Posts: 38
Topics: 13
Images: 26
Solve rating: 0
Joined: Fri Jun 16, 2017 6:23 am
Topics: 13
Age: 57
Gender: None specified
National Flag:
Spain
Apologies for intruding on the thread, but the same thing happens to me.

With this type of module (PCF8575) the leds of relays are weakly illuminated but are not able to activate the relays.

I have now requested the model that indicates Gio (PCF8575 2) to test if this works, the bad thing is that the design of my PCB is for the model that in principle does not work.

As soon as I arrive and can try confirm the module.

Regards,

Next



  • Similar Topics
    Replies
    Views
    Last post

Return to DIY Ferduino controller





Who is online

Users viewing this topic: No registered users and 1 guest