20M project board controlling relays

[michael boyd]

I am having an issue trying to get this thing to work correctly


Originally I had a different controller board. I changed it yesterday to the 20M project board and it seemed to work fine (I dont know why it suddenly worked. I thought that the old board had a issue). With the new board in place I had all the relays connected, powering up the various motors and soloniods.

However, a few hours later, once again would trip out ( as per video)

Once again, I have used seperate power supplies, batteries etc:
I have tried different 20m chips
Reloaded the program
changed the capacitor on the board

This issue has being going on for a couple of months now and feeling slightly frustrated as the circuit seems so simple however, still not being able to isolate the problem

any ideas are always greatly appreciated

http://www.youtube.com/watch?v=f4PVmTYocAk

 

[hippy]

Sounds like current surge flat-lining the PICAXE supply or EMI. Could be the relay contacts sparking.

Can you post a complete circuit diagram and a block diagram showing where the power supplies are starred out from etc, what voltages, supply regulation and capacitors you have ? Can you also post a circuit diagram of the relay board ? How much current does this motor draw ?

It may be a simple matter of putting a blocking diode between the main supply and the PICAXE +V so if the supply collapses it doesn't take the PICAXE with it.

Changing PICAXE or programs is unlikely to fix the problem.

 

[westaust55]

Cannot see the video (blocked) so some better description of when/how the tripping occurs would be good.

a few hours later, once again would trip out

What exactly is tripping?
Is the PICAXE resetting?
Is a protection device tripping.
Some clarity would be of benefit to analyse the situation.
How many hours later, 2,3 4, or other ?
Is the time duration relatively consistent (within some minutes)?

I have used sep[red]a[/red]rate power supplies, batteries etc

What batteries (voltage, type, mAh rating etc) are you using ?
Have you removed the link "LK1" on the AXE118 project board ?

Any particular function being performed at the time?

 

[michael boyd]

The PICAXE seems to reset.

The youtube video explains it well. I used a old kodak digital camera in video mode. the file extension is MOV. I know it runs in realplayer but not in windows mediaplayer 11. If you give me an email address, I will send it on.

I will do another post to send more attachments

Yes, the 12 volt plugpack is rated at 1.2 amps, and I have a soloniod that uses 2 amps. However worked fine for the brief time it was working.

Only one output (relay) is being operated at a time

I have done various tests using batteries. At one stage I replaced the plugpack with a 12v SLA 18AH/20HR and another 12v 1.3AH only running the relays (only one motor connected) , with seperate grounds. It still resets

 

[michael boyd]

The output pins from the picaxe go straight to the relay PCB, therefore I think the link (LK1) is not required

I now have the relay PCB boards powered up by 12 v, before I was using 5v

 

[MPep]

I would suggest adding 2 diodes. 1 to go from the PSU to the 5V regulator, and 1 to go from the PSU to the relay boards. Add a large capacitor (about 1000+ uF) on the line to the relays.
This should remove the glitches you are experiencing.

 

[michael boyd]

I made the changes as you suggested and attached the circuit to comfirm, however still resets as in the youtube clip.

 

[MPep]

Do you have access to an oscilloscope? You might be able to see what's happening with one. Failing that, a multimeter with a fast Max/Min function would help.

 

[Svejk]

You may get a voltage drop from that relay or load switched by that relay.

Try to move the load to another relay (so you can estblish if is the load at fault), then separate fully the logic supply from load supply and check again. If is the load it should reset your board on any relay unless the supply are separated.

 

[hippy]

Looking at scan001.pdf I would suggest adding a diode and cap for the 12V feed which goes the lower side of the relay board ( or move the diode and cap to where the PSU feeds into the 12V connection block ). Also add a cap for the +5V feed after the diode.

For reservoir caps I've always worked on bigger is better so you could try using 47,000uF.

You could also replace the PSU with a lab supply or something more substantial which can provide greater that 1.5A. If you use a lab supply with current limiting set to 1.5A it should give an indication if there's an over-current issue.

 

[azar]

Looking at scan001.pdf I would suggest adding a diode and cap for the 12V feed which goes the lower side of the relay board ( or move the diode and cap to where the PSU feeds into the 12V connection block ). Also add a cap for the +5V feed after the diode.

For reservoir caps I've always worked on bigger is better so you could try using 47,000uF.

You could also replace the PSU with a lab supply or something more substantial which can provide greater that 1.5A. If you use a lab supply with current limiting set to 1.5A it should give an indication if there's an over-current issue.

Just quickly reading through, any circuit with a micro and relay on the same pcb we generally place a diode across the coils of the relays to suppress back EMF which really does upset micros.

 

[BeanieBots]

In addition to all the advice given, try to find out which relay and the root cause.
First off, remove any loads from the relays and see if it is just switching the relay that causes the problem.
Then find out if it is just one or all of the relays the cause it.

Once you know that, you will have a much better chance of targetting the specific type of interferance.

 

[michael boyd]

hi

sorry for the delay

I basically started again through frustration to see if I would get a different result.

I used a 20M project board with ULN??? darlington driver. I powered this with a 12 volt powerpack. I bought a bigger capacity one that can handle the load.

The 20M is powered by another plugpack, 5 volt.
The 20M with relays seem to be working fine

I have added vaious capacitors and diodes and still seem to have one issue

I think I will start a new post

regards

Michael