too many BOB options

 
Hi all,

this is my first post so I thought I'd better do a bit of an Intro.

I am in the throws of converting my diy GRBL router/laser to run a plasma cutter and I am thinking I will (be forced to) ditch GRBL and have a run at linuxcnc, mainly to run a THC and auto squaring the gantry. So it's a steel machine (~600 x 900mm cutting area) I've made from looking at others (and bashing my head against the wall) using v-groove bearings running on steel angle, with acme leadscrews. Currently, I am/was running TB6600 drivers with nema23 (2mH) along with 2 x 24VDC unregulated power supplies with an earth leakage circuit breaker and a power filter, I found one of the drivers had died after moving interstate (back to Qld Australia), it may have had something to do with a ~20hr laser job I ran not long before packing it up. So I have now ordered some DM542 drivers to replace the TB6600s. I also haven't got any homing switches connected as yet, I guess i require 2 inputs for gantry squaring. I also have a standalone THC that will send up and down signals.

Anyway, I have done a fair few mech updates since moving and I have found an old pc with a parallel port so I will start with that and a BOB. I will definitely consider an ethernet mesa board in the future but seen as mesa boards are in short supply and I can't wait, so a BOB it is.

I have installed linuxcnc and learnt a heap so far, the help given on this forum is amazing. I have never used linux before so there's a little learning curve there too. I have played with show hal which IMO is fantastic, I am an electrician who enjoys PLC work so it is great to see nice fault finding type tools like this built into the software. I've used show hal to prove that the old PC's port is still functioning as it should which is handy. But now I need to get a BOB on the way so I can get this thing on the move again.

I have done some searching but I can't find any decent info on a particular BOB that I have my eye on.  But I'm hoping someone on here may help me out. So I've attached 3 different BOBs I've found on ebay, the one with 3 relays is the one I am interested in most. It seems to have everything I should need, i think. Does anyone have any advice for me? The sellers on ebay have all sold a lot of them, not that that says much. See pics and this link for more.

3 Relay BOB - info in description

The BOB with the hand control option doesn't even appear to have opto couplers, which seems to be a bad idea and I'm not sure about the quality of the cheap BOB. There's thousands of the cheap BOB ranging from $7 - $60 AUD and they all look the same, are they, I don't know??

I want the option to swap between the laser, router (no speed control, maybe later) and plasma, so I guess I will want at least the following features.

- PWM for the laser, I presume I can change the range of the 0-10V PWM to suit the laser, I haven't found much on this. 
- 2 relays would be nice (coolant, air assist, router, vac etc)

Sorry for the long post but I feel the intro was required. Any other options I've over looked? I'm open to getting any BOB as long as it can do the job with minimal fuss. Any help will be greatly appreciated.

thank you.
 

cheers  tommylight , I'm glad to hear its doable. I seems like it could be very easy to overlook something and be left without all the right options. Have you or anyone else reading this had anything to do with that BOB in particular? There seems to be so much rubbish out there with respect to any/all electronics these days.  

I haven't bothered with the enable option with the current setup so, to be honest I hadn't given it a second thought, but i did notice that the 542s will hold at half current. So thanks for pointing that out. I have been considering change over plugs and/or switches for any options that might be needed for one of the tool options, but if I don't have to that'd be awesome. I am not concerned with running any tools together.  

 

Aha, I thought I'd looked at all the ethernet options and they were out of stock but clearly not. The extra IO etc would certainly be helpful. I am a bit thrown by the postage though, it's >50% of the card price from mesanet.com and mesaus.com. I've sent motorbike engine parts to and from the US before and there wasn't much difference in price to a card that weighs next to nothing. I've tried some of the links I've found on the Mesa Suppliers  thread for other suppliers but haven't had any luck finding others with any mesa cards, are these the only options out there?

thanks again

thanks again, I will have to check with the minister of finance and see if i can spare the cash.  If not I guess I will have to take a punt on one of the BOBs out there until the machine makes some money.

kazafog wrote:

thanks again, I will have to check with the minister of finance and see if i can spare the cash.  If not I guess I will have to take a punt on one of the BOBs out there until the machine makes some money.

In .AU (like me) I would just order a 7i96s from Mesa direct or possibly from BigJohn. mesaus.com/
The closest Distributor is in NZ.

Yep sure am, in central Qld for the moment.

if the minister allows it I will order one shortly. It's funny I was just listening to one of your youtube vids when your name popped up in a notification. Thanks rodw.

permission granted. 

I believe I have ordered the 7196s card, the order failed on timeout errors. Then I changed credit cards and i got a thanks for your order but there is no order or transaction listed and no money has moved from the card, time will tell. I flicked them a message, so I will find out sooner or later.

I guess the thread name is a bit useless now but anyway, thanks again. Hopefully I can work it all out once it turns up.