Connecting relay to digital outputs

Hi all, I was wondering if anyone could help me out wiring a relay to my breakout board to control my kress spindle to turn it on/off in uccnc.

My breakout board is a uim2901-5a and has spare outputs on pins 1,16 and 17.
Charge pump is connected to pin 17.
Each output pin has 2 terminals a collector and an emitter and after some research I failed to find another board with a similar set up ie, collector and emitter pins most setups I've seen just have a output terminal which is shorted to ground.

I have connected a wire from the 12v psu to the IN+ on my 12v relay then taken another wire from the IN- to the collector terminal of pin 16 and finally a wire from the emitter pin to ground on the psu.

When I switch spindle on in uccnc the relay doesn't trigger, I've disconnected the relay and measured the voltage between the 2 wires that it was connected to and I get 0v when spindle control in uccnc is off and 12v when I toggle the output on so I can't understand why the relay won't trigger I've tried 2 different types of relay a ssr and a emr which both work perfectly when connected directly to a 12v power source.

Can someone please help me, am I missing something here do need any additional components ie, resistors etc.
I have attached a pdf of the manual for the breakout board.

Many thanks in advance

Derek Attachment 28473

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Are you talking about a 12v coil relay or a 12v relay module like one of these https://uk.banggood.com/12V-1-2-4-8-...r_warehouse=CN

I ran my Kress spindle for 5 years using a relay to switch it, now I have converted to a SuperPID speed controller and the difference in noise levels is amazing. It is much quieter.
One of the points to be aware of is that the control signals to the spindle relay can be all over the place until Mach3 takes control, so you could get the spindle starting and stopping as the computer boots up and before Mach3 takes control of the port.

Hi Cropwell, the first relay I tried was a Fotek solid state relay and the second relay was a mechanical one pictured below.

Have ever connect these types of relay before?
https://uploads.tapatalk-cdn.com/202...d814327942.jpghttps://uploads.tapatalk-cdn.com/202...6ed5a27143.jpg

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Derek - the Fortek - was that one of the "usual" 20-30A SSRs?, many of the cheap trial-based SSRs require a 30+ VAC switching voltage. But, you should have been able to get the LED on the unit to light/extinguish on demand. That I'd be looking at in the first instance to confirm.

For the relay, with the BOB - use the onboard relay configured through J5/J6 to provide direct 12V switching to the relay that you have. My thoughts are that the onboard Opto may not switch enough current for the relay you have - using the onboard relay to drive your relay should be reliable.

As Doddy says, the opto may not give enough current to switch the relay. I used the 'arduino' opto isolated type of relay module that uses 5v at very little current for switching and I just drove it off two of the outputs (A or B step/Dir), one for the spindle and the other for coolant. I had an onboard relay for the spindle power or coolant pump, whatever, but never used it. It seems the simplest solution for you to use the onboard relay.

Hi Doddy, yes it is a Fotek ac/dc ssr with a switching voltage between 3 and 30v dc, I had it wired to p16c/p16e of bob and when I toggle it on/off in uccnc the led would come on and off.

The ssr was wired to a ac chassis socket to plug kress spindle into, but when the ssr was switched off I measure voltage across the chassis socket pins and was shocked to see I had 246v when it was supposed to be off and in an open state, I even disconnected the dc supply just to make sure it wasn't getting any voltage from the bob and it still showed 246v.
A quick Google search and I discovered that other people have had similar issues with them failing closed unlike a mechanical relay.

Yes I see what you mean now by using onboard relay to control the external relay used to switch ac power so will give that a go and fingers crossed I'll be successful!

Many thanks for your time I'll let you know how I get on.

Cheers

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Those SSR's are not meant for switching inductive loads. I have used them for switching heating elements, but back emf from a motor can bugger them.

Hi Cropwell, yes I see where your coming from in respect to using step/dir from A/B unfortunately for me my board hasn't got a B drive output and I'm using the A drive to run second ballscrew on the 'Y' axis slaved to 'Y' so will have a go wiring the external relay through the onboard relay.

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Yes you are right that type of relay is not meant to switch inductive loads as I found out after some research, what I needed was a random turn on type, although I hadn't got to the point of connecting the spindle before discovering something wasn't right with it.

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Quote:

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Originally Posted by derekm06021970

The ssr was wired to a ac chassis socket to plug kress spindle into, but when the ssr was switched off I measure voltage across the chassis socket pins and was shocked to see I had 246v when it was supposed to be off and in an open state, I even disconnected the dc supply just to make sure it wasn't getting any voltage from the bob and it still showed 246v.

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Be interesting to repeat that with a proper load (I assume you threw a DVM across the terminals?), you'll probably find a snubber circuit across the switching triac in the SSR to drop the switching noise - and the DVM will see the nominal terminal voltage. Add a load you *might* find that the voltage drops towards zero. Of course, the SSR could also be buggered.

But... relay... KISS.