Matho's controller

[Sammus]

Here's a pic of it all wired up.

No brewery yet, but I figure is the controller thread so controller pics are ok

 

[wotafm]

just a quick question for you all.



how many are using 240v pumps and if so have you had to add an Induction Suppression Capacitor across the pump terminals to stop the display going nuts when your pump stop.

 

[Sammus]

Haven't actually hooked mine up yet, will sus it out soon and let you know

 

[matho]

just a quick question for you all.



how many are using 240v pumps and if so have you had to add an Induction Suppression Capacitor across the pump terminals to stop the display going nuts when your pump stop.

I was a bit concerned about that but on my PIC based controller I didn't encouter it. Is it just the screen or is the arduino stopping as well.

something like THIS should work but it is bulky, you can connect it across the load if need be.
When I get the time I'll connect my march pump up and see if I get the same result.

cheers steve

 

[PeteQ]

just a quick question for you all.



how many are using 240v pumps and if so have you had to add an Induction Suppression Capacitor across the pump terminals to stop the display going nuts when your pump stop.

I definitely had this problem but tried to go for the simple route before I looked into suppression capacitors.
I wrapped the 240V twin going into the pump relay with aluminium foil and covered that in electrical tape so there was nothing exposed. I took an earth and soldered it onto the al foil closest to the 240V components then more electrical tape to secure it. It took all of about a minute and I haven't had a problem since.

Cheers

 

[adryargument]

just a quick question for you all.

how many are using 240v pumps and if so have you had to add an Induction Suppression Capacitor across the pump terminals to stop the display going nuts when your pump stop.

March 809 HS on my controller... No issues what so ever...??

I am using a slightly modified control box with 4 extra LED's and manual on/off switches for the pump / element.

(3 vessel system)

 

[wotafm]

Steve

it was a bit of a mix most of the time the display just displayed rubbish but once or twice the controller stopped.

i have put one of these here

i had it in my box of bits and it seams to be ok i will be trying to do a brew on the weekend so time will tell


dave

 

[Davethebrewer]

I'm planning to mount a small plug in type relay in the base, 12vdc coil with 240vac 10a contacts, this keeps the 240v away from the pcb and will be easy to replace should it ever crap out due to motor starts or shorts.

 

[Sammus]

I'm planning to mount a small plug in type relay in the base, 12vdc coil with 240vac 10a contacts, this keeps the 240v away from the pcb and will be easy to replace should it ever crap out due to motor starts or shorts.

How does one of these work? I thought the pump terminals on the PCB were just basically a switch, so no power to drive a relay?

 

[MastersBrewery]

How does one of these work? I thought the pump terminals on the PCB were just basically a switch, so no power to drive a relay?

Correct, pump terminals are basically just a switch, the controler uses a 12v supply, so those with a 12v pump can use that for power, otherwise the 'switch' can handle 240 but the seems to be an issue for some. Matho has some great diagrams in the PDF dowload that would give you a better idea. However what some are finding is the current from a 240 volt pumps is creating interferance with the board so sheilding the 240 maybe required.

my 2c correct me if I'm wrong lads

 

[Sammus]

Correct, pump terminals are basically just a switch, the controler uses a 12v supply, so those with a 12v pump can use that for power, otherwise the 'switch' can handle 240 but the seems to be an issue for some. Matho has some great diagrams in the PDF dowload that would give you a better idea. However what some are finding is the current from a 240 volt pumps is creating interferance with the board so sheilding the 240 maybe required.

my 2c correct me if I'm wrong lads

Thanks, but that wasn't what I was asking. I was asking how Davethebrewer hooking up a relay across the pump terminals to drive 240V will be possible, or if he's using some special kind of relay. If he uses the kind of relays that I know about, then to actuate the switch in the relay you need some current across the drive terminals, this energizes a coil inside the relay that physically opens or closes a switch on the other side. If you just short the drive terminals, nothing will happen.

 

[blotto]

Thanks, but that wasn't what I was asking. I was asking how Davethebrewer hooking up a relay across the pump terminals to drive 240V will be possible, or if he's using some special kind of relay. If he uses the kind of relays that I know about, then to actuate the switch in the relay you need some current across the drive terminals, this energizes a coil inside the relay that physically opens or closes a switch on the other side. If you just short the drive terminals, nothing will happen.

Yeah but you can use the 240v pump terminals to switch the supply to a relay and the relay switches the supply to the pump.

 

[Sammus]

Yeah but you can use the 240v pump terminals to switch the supply to a relay and the relay switches the supply to the pump.

doh, of course. Thanks for clearing it up

 

[Davethebrewer]

Yeah but you can use the 240v pump terminals to switch the supply to a relay and the relay switches the supply to the pump.

Yeah that's what I had in mind, doubling up the relays but has benefits I think, going to gland my cables into the enclosure so I can use a 3kw element, so should have room to mount plug in relay.

 

[Sammus]

Yeah that's what I had in mind, doubling up the relays but has benefits I think, going to gland my cables into the enclosure so I can use a 3kw element, so should have room to mount plug in relay.

Hmm, I wonder if I can fit one in my box somewhere? I could just chuck one of those suppressor caps across the pump terminals I guess, I do like the idea of isolating the pump from the controller board though.

Will putting in a second relay really solve it? isn't the pump already behind a relay?

(sorry if im inadvertently using jargon incorrectly, im not an electronics guy )

 

[MastersBrewery]

Hmm, I wonder if I can fit one in my box somewhere? I could just chuck one of those suppressor caps across the pump terminals I guess, I do like the idea of isolating the pump from the controller board though.

Will putting in a second relay really solve it? isn't the pump already behind a relay?

(sorry if im inadvertently using jargon incorrectly, im not an electronics guy )

essetially what your trying to achieve is to increase the space between the 240v and the control board to reduce problems with Electro Magnetic Interference (EMI), so running say the 12v supply through the onboard relay to switch another relay that is switching your 240v pump will work will work so long as you as much as posible locate the 240v away from the control board. Thats the basics one of the electronics wizards here would have a better idea of how close is too close, and shielding the 240v would help this greatly as metioned previously.

 

[Sammus]

Yep, confirmed my display scrambles occasionally when I start the pump. Probably 1 in 5. I think I'll try the foil shielding thing, then get one of those caps that matho linked if that fails.

 

[Sammus]

Yep, confirmed my display scrambles occasionally when I start the pump. Probably 1 in 5. I think I'll try the foil shielding thing, then get one of those caps that matho linked if that fails.

I double shielded and earthed the shields on all the 240V lines with foil - heatshrink - foil - heatshrink to no avail! D:


Works fine with the switch on 12V though, and on 240 I don't even need the pump hooked up and it does it. Flick the pump on and off a few times and the display scrambles... Any ideas? Will one of those capacitors fix it? Is something like these just as suitable?

 

[Sammus]

Or is there something in jaycar that's suitable I can get today?

These and and these look similar I guess, not sure if either of them are suitable.

 

[matho]

The arduino seems very susceptible to noise, the noise is produced by the switch when switching an inductive load like a march pump. sheilding of the wire would not produce much of an effect. The way to reduce noise is to suppress the arc across the switch with a rc suppression network, also to reduce the susceptiblity of the arduino to noise we could look into decoupling the power supply more by adding more capacitors but maybe just concerntrate on suppressing the noise first. Adding another relay to the pump circuit would not reduce the emi produced but it would just remove it further from the board which could help but arc suppression is probably the best way to do it as it also increases contact life. When I get a chance I'll look into it more

Cheers Steve