[Mr.Chips]

Has anyone used the “PBX-RF Radio Frequency Isolated CNC Breakout Board
Isolated CNC INTERFACE from Probotix that sells for $49.99?

Please comment if you have any experience with this board.

http://www.probotix.com/breakout_boards/PBX-RF/

Description:
Parallel Port Breakout Board
DB25 Female
Flexible Design
Onboard LM-317 Based 1.5 amp Logic Supply Regulator
USB Logic Power Supply
Optional Pinheader and Screw Clamp Connections
Jumper Enabled Limit Switch Pull-up Resistors
LED Power Indicator
All Pins Brought Out

[Mr.Chips]

Anyone???

[bitbanger]

I'll comment because I know you will likely not get much response, as this is a brand new product.

This basically accomplishes the same thing as an opto-isolator, except the isolation chips use radio frequencies, rather than light to perform the isolation.

What is nice is that the PC side can be powered from USB, and there is an on-board regulator for the logic side of your drivers, as well. On-board pull-up resistors for your limit switches, and a non-isolated e-stop input (so that e-stops get signaled regardless) make this a really nice board.

>Len

[Mr.Chips]

I'll comment because I know you will likely not get much response, as this is a brand new product.

This basically accomplishes the same thing as an opto-isolator, except the isolation chips use radio frequencies, rather than light to perform the isolation.

What is nice is that the PC side can be powered from USB, and there is an on-board regulator for the logic side of your drivers, as well. On-board pull-up resistors for your limit switches, and a non-isolated e-stop input (so that e-stops get signaled regardless) make this a really nice board.

>Len

The USB feature is a nice touch. Guess the radio frequencies would be as reliable as the Led light.

In their comments they recommend using a add on parallel port rather than use the built in parallel port, even though it is isolated. Seems to me that if a stray signal went back even with a add on board it would not stop just at the add on parallel port, wouldn't it go opn down into the motherboard?

Think it mentioned "Charge Pump" but didn';t give any details on this feature, could you comment?

Want to be sure I understand what I might be getting into.

Thnaks
Hager

[bitbanger]

I thought the "biased opinion" would indicate that I am PROBOTIX. Sorry.

I always recommend an add-on parallel port card, as you can never be too careful. Having said that, I have run many non-isolated systems successfully, but I have also blow out parallel ports from stupid mistakes I've made. You'll have to take that for what it is worth.

The charge pump indicated, is actually a re-iteration of a commonly mis-used term. In this case I mean it to be the logic supply regulator section. This is not the same "charge pump" mechanism used by Mach3 software, which monitors a pulse out to disable the drivers if the software does not have control of the parallel port.

[bones]

Hi,
Nice work on the breakout board. I like the USB to power the logic.
How come you used 317's instead of a small switch mode? Price I surpose.
Just wondering what chip uses Radio Frequency Isolation?
Never heard of one, but a good idea.

From a electronics persons idea, it looks like a good board.
Well designed and layed out.
The screw terminal look like a decent usable size.
The main thing I like is the supply of the schematic.
You can check the design quality straight away with it.
Nice job.

Cheers
Rodney

[dougputt]

the hilbilly BOB works very well, take a look at it

[dertsap]

http://cgi.ebay.com/CNC-PLASMA-ROUTE...QQcmdZViewItem

this guy has a nice board , ive got the older style and it works great

[bitbanger]

The LM317 is a great chip and can handle the higher voltages while still delivering 1.5amps. Granted, I do not need that much on the PC side of the board, but it's an economical benefit for me to have to stock fewer part numbers.

The isolators are ADUM1400 from Analog Devices. The are designed to handle the higher switching frequencies of modern devices, which is not necessary for driving stepper motors. I chose them for their footprint, mostly.

[bones]

Nice chip. Thanks for the info

[harryn]

Hi, I am in the market for a isolation / break out board. I saw that Probotix sells two versions, but I am not entirely clear on the difference / benefits of the $ 25 vs $ 45 versions. I don't mind paying for features, I would just like to understand what I am buying.

Is there a difference between these and the relay board ?

Thanks for the insight.

HarryN

[bitbanger]

The cheaper version is not-isolated, therefore it is more of a risk since you will be connecting motor drivers directly to your parallel port. I always recommend using an add-on parallel port card as an additional layer of protection.

I have run non-isolated boards for years with no problems. I have also blown out parallel ports by making stupid wiring mistakes. The choice is yours, but you have been warned.

[harryn]

Thanks for posting this, and for the email reply as well.