old 3G control board

[steve_g]

I've been searching, without success, for a schematic of the old 3G control board. I'm helping my brother long distance and am wondering if the 3G board has relays for turning the router off and on, It currently uses a light switch mounted on the side of the table. Was this par for the course back then?

SG

[bleeth]

Don't think so Steve, The on/off controls for spindles was put together for the Gecko boards first.

[steve_g]

Thanks Dave...that was my suspicion

SG

[Brady Watson]

Steve,
You can buy a relay board from SB with full documentation, or buy a relay board from Winford Engineering and figure it out on your own. Either way, it is completely possible to turn the router on & off with either relay board. You will also need a 24v power supply (all over the place on Ebay) for the board to function correctly. Here is the documentation for the SB 5-position Relay Board currently sold by SB: http://www.shopbotdocs.com/Relay-Board.html - It will work with any model SB.

-B

[jerry_stanek]

I made my own relay board for my old bot It used 12 volt

[jerry_stanek]

here is a link to the one I built
check out this thread go down to the 8th post and that is the one I built

http://www.talkshopbot.com/forum/showthread.php?t=14460&highlight=relay

the relay I used was this one

http://www.radioshack.com/product/index.jsp?productId=12505678

[Brady Watson]

I almost posted that, Jerry...But, if you read the fine print - SB advises against using it to turn the router on & off because there is no protection against the relay kicking on - from any number of reasons, including static from the DC you left running while changing the bit.

I don't want to come off like the 'Safety Police', but whoever builds one of these devices NEEDS to ask themselves one very simple question: How much are your hands worth to you?

SB has a safety interlock key attached to one of the spindle/router wrenches there as an absolutely safeguard against the router accidentally coming on. This should be duly noted, and whoever builds their own deal should certainly install the same kind of switch in conjunction with ANY of these relay boards, including the SB one.

-B

[steve_g]

Thanks for the feedback guys...

Has anyone ever had a router/spindle turn on un-expectantly? Is this something that should concern me when changing bits on my Alpha?

I like the looks of the Winford Engineering relay board, I think that's the route I may go. I have a solid state 18 amp relay I wanted to use. It is controlled with 3 to 15 volts and draws 15 ma. Not knowing the specifics of the capabilities of the TTL outputs of the 3G board, I better stick with something someone else has tried successfully!

SG

[jerry_stanek]

I almost posted that, Jerry...But, if you read the fine print - SB advises against using it to turn the router on & off because there is no protection against the relay kicking on - from any number of reasons, including static from the DC you left running while changing the bit.

I don't want to come off like the 'Safety Police', but whoever builds one of these devices NEEDS to ask themselves one very simple question: How much are your hands worth to you?

SB has a safety interlock key attached to one of the spindle/router wrenches there as an absolutely safeguard against the router accidentally coming on. This should be duly noted, and whoever builds their own deal should certainly install the same kind of switch in conjunction with ANY of these relay boards, including the SB one.

-B

What is the safety feature of the one that Shopbot sells. I have one and the only thing they tell you is to jump the number 4 and number one relays. so the board is really only like a 3 relay board.

[Brady Watson]

Jerry - You might have one of the early boards. The new boards are 5-position, which gives you 4 relays to work with.

No - there is no 'safety' provision on the relay board. This is why all the newer tools have the key on one of the wrenches, as a secondary disconnect to be 100% SURE there is no possibility of turning on when your changing bits. Perhaps I will mention this to SBHQ and see if that can be added to the relay board bundle as an option.

Steve - There is always a chance that it could happen. I like to err on the side of safety when it comes to my mitts...My machine is still set up old school - where the only thing controlling the spindle on/off is me via the VFD keypad. Since there is ALWAYS a chance that electronics can flake out, I'll take the responsibility of turning it on and off. It would be nice for it to turn off the spindle for me at the end of a file...but then again, I am supposed be be an operator while the tool is running, and not eating bon-bons watching TV.

Now...the key is a pain in the arse - but it is there to protect you. Please, at the very least - put some kind of secondary switch in place that lets you completely disable the relay or power from the spindle just in case. I have seen many PR and PRT tools where customers wired up a 110v light switch on the Y car for this exact purpose. I have personally witnessed static charge interference 'blipping' an output, causing it to activate the output for a plastic welder I setup for a customer. This is different than a spinning tool, and we wound up toggling 2 outputs instead of just one for the trigger.

All I'm saying is, things can go wrong when you least expect it. Something as stupid as an aluminum chip landing on that old 3G ATX case could bridge terminals together...I have actually seen this in my travels...so all I'm saying is err on the side of safety. I'd like to shake your FULL hand some day.

-B

[ssflyer]

Hmm. While anything is possible, I find it extremely unlikely that my spindle could turn on unexpectedly, on my PRS Alpha. Even if a glitch turns on the output, I'd still need to trigger the relay that actually starts the spindle.

[Brady Watson]

Hmm. While anything is possible, I find it extremely unlikely that my spindle could turn on unexpectedly, on my PRS Alpha. Even if a glitch turns on the output, I'd still need to trigger the relay that actually starts the spindle.

A static spike can start it for you, when you least expect it. It's kinda like, "I didn't know it was loaded!"

This is why newer tools have the key interlock...

-B

[jerry_stanek]

I am not familiar with the new inter lock system. When you do a tool change does the controller shut down.

[Brady Watson]

No - it shuts off the contactor to the router.

-B

[GeneMpls]

SB has a safety interlock key attached to one of the spindle/router wrenches there as an absolutely safeguard against the router accidentally coming on. This should be duly noted, and whoever builds their own deal should certainly install the same kind of switch in conjunction with ANY of these relay boards, including the SB one.

-B

Hi Brady (or anyone) what does this safety interlock look like? Anyone
have a picture- sounds like a good idea. Thanks Gene

[coryatjohn]

Hi Brady (or anyone) what does this safety interlock look like? Anyone
have a picture- sounds like a good idea. Thanks Gene

It's a key securely attached to the collet nut wrench. The key goes into a small lock/switch that cuts the power to the relay for the spindle. In theory, it would be impossible for the spindle to have power with the key out or in the off position.

[jerry_stanek]

So if you wired a key switch inline then attach the key to the spindle wrench you would have the same thing.

[richards]

Look into using latching contactors. They require that you press a momentary switch to latch the relay on and then they stay on until power is removed. The same principle was used by Shopbot on the PRT-Alpha that I owned. Because the contactor required an extra step, it couldn't turn on accidentally. Contactors are available with 12VDC, 24VDC and AC coils.

[jerry_stanek]

If I have to press a button to turn turn the spindle on then why use a relay. I had to do that before I got my relay.

[ssflyer]

Actually, I think it's the same way on my PRSAlpha - momentary contact turns on, any interruptions, stays off - latching contactor. Can't see any way a spike will turn it back on...

[Brady Watson]

If you go back and read the very first post, Steve references a 3G setup. There were no interlocks or buttons on standard (or Alpha) tools back then. A lot of things have changed in the meantime.

-B