as per title really what does everyone use? and why?
there is a big choice around ranging from £15 to £50+
i already have an idea which one to use just curious what most folks use on here
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as per title really what does everyone use? and why?
there is a big choice around ranging from £15 to £50+
i already have an idea which one to use just curious what most folks use on here
That's a good question Wilfy & something that I am not sure about either although I did purchase a breakout board from diycnc. The uniport V2 I know I could have bought a board cheaper as I don't need most of the functions on it but had no idea what to get.
The drivers I have are already protected so no need for the opto isolation, the spindle will run through the super Pid so no need for the spindle relay, 5v supply will be from an old computer power supply so no need for the usb connection. Probably other things as well, it wasn't a cheap board at all I just didn't know anything about them when I bought it.
Yep, definitely a good question, wilfy. I was asking myself that question last week when I managed to fry my previous pcpps board from diycnc. Entirely my fault, nothing wrong with the board.
After an evening of research I went for the v4 version of the same board. Its basic (no opto isolation, no led status indicators, charge pump doesn't directly disable outputs just sets a voltage you can use to do it yourself), and is perhaps a little pricey at £18, but its still the best option I could find. Below is my quick review having wired the new one up.
+
Quickly shipped from the UK. (no idea where its made)
Does the job
Sponsor this site
5v supply on board
-
So little documentation on the charge pump output (a key feature of the board) and how to use it that i, ummm, don't use it.
Documentation not great (how to connect to it? pull ups or pulldowns? how fast is it? Not much info on the web)
V4 mounting holes are a different pitch to V3
Outputs are inverted compared to V3 (not a huge deal, just re-invert in software)
Like I say, its the best option for my needs and I'm about to buy a spare, but the documentation really needs to be improved.
:thumbup:
I too did loads of research when I was looking for a decent BOB and although a little pricey too at £110 delivered but ive had no problems with what is actually a well featured board and has ok documentation as well, Ive had about five now, with no problems ive not bought one for some time now so i suspect there is another version...Quote:
Originally Posted by Tom
Opto-BB-V1
Rick
Rick, you say you did loads of research before opting for this board so what made you decide this was the right board for you. That's what we are trying to understand better, why people chose the bob they do over any other board on the market. Well I am anyway lol & I think that was the point of Wilfy's post.
Quote:
Originally Posted by martin54
Ahhhh Well, For the money it has a fair few features that i liked..
Opto-Isolation on all input and output pins, so no stray voltages getting where they are not wanted..In my computer for a start, no noise leaping through from or to the computer, the site says about the 1Mhz operating frequency, but to be fair thats not a selling point to me although maybe it has a factor for some people, The charge pump gave me an added level of control not present on the smaller boards, and not to mention the lights (I like lights, ask i2i, LOL)
Leds on all inputs and outputs told me when mach was doing something or not, almost like a little diagnostic feature built in, One look tells me that Mach has sent the signal because the led changes state... and the documentation was there to be downloaded before i even commited to spending any money, And the instructions for seting up mach are right there in the Document.. dont get me wrong it still suffers from the limitations of all Parallel port Bobs IE not enogh inputs, so i cured that and i buy the pokeys55 for as many as i want via the USB port right into mach3 with the included plugin...
The simplicity of the bob won me over when i fitted the first one...I read the documentation, I connected it up, it worked and and still is... and so are the others ive fitted since then.
Rick
I have used a variety of B.O.B's and currently use a PMDX-126 with a ESS attached. This has gotten rid of noise and signal issues and allows for the repeatability and acceleration that allows me to get work done in a reasonable amount of time and still keep things accurate to very tight tolerances.
I have used one of the older PCPPS (v2 or v3) with charge pump and power-save function. I upgraded from a System 4 BOB that I was using the ext modules to control AM882 drivers (secondary power supply to the drivers and a 24V power supply to the board).
Things to look for on a break out board are the voltage it can handle (this keeps your signals clean, less chances of false or lost signals) Opto-isolated is useful to keep from having problems with power feed back and signal noise. This bumps over into your limit switches and index plate (touch off/datum). If it allows you to use a secondary power source for the drivers that helps protect the BOB and your computer by limiting the pathways for back EMF during breaking on the steppers or the servos. If you are primarily a hobby CNC person then the PMDX type BOB is over kill in the extreme. If you plan on doing production work and need the precision, than it is different story.
Once again it comes down to when doing a design or build in DIY CNC you really need to follow this pattern that I was taught and it works. Which is:
- Write down what you want the machine to be able to do
- Seriously look at your funding options
- Ask questions ad look at different designs. Ask why some work and some don't. Don't take anyone persons word for the whole answer (we all have biases).
- Redesign again (you will do this a couple of times at least and will get good at either drawing or using your chosen CAD software)
- Sub note here. You really want to look at CAD software with an eye to what can be used with your future CAM software as once you get comfortable with it you really don't want to learn a new one (trust me on that one:joker:)
- Look at cost options of what you are building. Also talk to folks to see who has what that they are willing to let go for cheap or are willing to help someone else out. DON'T expect folks to hand you everything or tell you everything to do, you DO have to learn and study and take the knowledge base on board and it is not simple. There is a lot to learn.
- Redesign again (yes you are getting sick of it about now and I bet you forgot to put in index plates or rebates for indexing or to account for wiring paths, shielding from swarf where needed or dust shoe mount [I am talking from experience of making more then a few of these mistakes])
- When doing all this design You need to also think about how easy is it going to be to service and upkeep. Unless you like buying new parts often.
- Now that you have a design you can live with and will most likely work (depending on which of the above steps you skipped or did not take advice on board from folks with as much or more experience then me and I am low on the list). Start sourcing your parts and look at budget and time you can put in.
- Start working with folks to get parts cut if need be and get the measuring and set up tools you don't have in place to make sure it goes together square, true and plum.
- Write down the build steps you plan on using and follow them (double checking keeps you from missing something (trust me on that one and you still need to triple check everything).
- Get your control software set up and start getting to where you have a basic knowledge of what is going on.
- By now you should be far enough in your build that you are asking a new set of questions and are beyond the basic starting position of a build and doing DIY CNC type set up. Have fun keep learning and keep asking questions.
Michael
PS I know I went a good bit off topic but the way the questions and replies where going I though it might be useful.