Renishaw Probe OMM, How it works deep dive

[@revanur]

This is good stuff, really deep. You are revealing all the secrets! Keep it up. PS: I work for Renishaw :)

[@AtManUnlimitedMachining]

Na, just the 20 year old secrets ;)

[@sjb_rnd]

Hey Tim, This is very interesting work. Thanks for sharing.

[@AtManUnlimitedMachining]

Thanks Stephen

[@oldschooloutlaw6522]

I found a tp1 and cord , a ph6 with a tp2 along with a ( can't remember exact name) but it allows you to angle the tp2 5w and 3 extentions I found these at a flea market and I got the deal of the century . I paid 5 bucks that's right $5

[@gorak9000]

What is the other video you're talking about at 1:22:40? Watching this (or listening to it) as I'm fixing a power supply for a spindle drive on a Mitsubishi machine that's suddenly taken up residence in my garage... excellent info on the Renishaw probes - might just have to build myself a receiver and get a used probe, once I get my machine running!

[@AtManUnlimitedMachining]

Here is Brian's video, scary, 6:10 kzbin.info/www/bejne/ZnLOoGidqt6thMk

[@jasongallahair2418]

enjoyed the deep dive, do you have any plans to cover the macros and use of the probe?

[@AtManUnlimitedMachining]

Hello Jason, Yes at some point. Not sure on the time frame though. Lots of stuff on the lists.

[@billschnoebelen40]

Very good explanation! I started watching yesterday and I am only half way thru it. It is a lot to take in. BTW: I am slowly trying a opto switch to replace my blum toolsetter. I believe I just need a very repeatable circuit with 24 VDC out. My plan is to remove all the complex mechanicals of the blum and just use the opt switch.

[@AtManUnlimitedMachining]

Hello Bill, thank you, you can use an optical method, some machines have laser systems that not only measure length and diameter, but can also measure the radius of a tool. One thing to keep in mind though with optical, you want a good air blast to blow off the tool. Any small chips or even a drop of coolant can skew the offsets.

[@AtManUnlimitedMachining]

Nice Bill, hoping to get my Fadal to do the same!

[@kentvandervelden]

Very impressive piece of work. I'll check out some of your other videos using the NI products. I was looking at a DAQ mainframe.

[@AtManUnlimitedMachining]

Hello Kent, Thank you There are not to many videos showing NI hardware. I think only the interfacing with NAS video. But this is only what I did in a few hours, I work on some really hard stuff using NI products. Send me an email if you would like more info, I will get you my other email contact for my day job. I'm a certified LV architect and do a lot of work with controls and monitoring systems. Tim

[@Steve_Just_Steve]

+Kent Cool channel! New sub here!

[@engnerdan]

Do you want some oscilloscope screen shots from testing the new style probes, showing the IR timing pulses and the reset when the probe is activated? I did a little work reverse engineer the OMP 40-2 on the Haas VF2 I have a work. I also have all the macro programs from the Haas if you are interested. I dreamed of developing my own Arduion based IR optical based system for use with a typically wired probe and then implement them into my KFLOP controller on my cnc mill. But I have 1000's more ideas than I ever have time to execute.

[@AtManUnlimitedMachining]

Hello Dan, thanks for the offer. I do have the macros that are for Fadal, so I'm good there. As for probe data, your welcome to send it and I can take a look, email is in the video description. I don't have an OMM2 or OMI that will work with the newer probes though. If I do end up with a newer probe I was just going to run it in legacy mode to work with the OMM I have now. If you do end up trying to make something I would try that, the old protocol is much easier but not as robust. Thanks Tim

[@bstevermer9293]

I could have missed it, Have you done a intro to electricity video? What is a amp, volt, watt. You are right it's tuff to learn what u can't see. Good job!

[@AtManUnlimitedMachining]

B, I have not yet, coming soon though. Most likely this week or next. I was going to film it last night or today but it needs to be done outside and its been raining so far.

[@alexalex-fu1eo]

Super ! Thanks

[@jsflood]

Great video, tnx. btw. I was number100, any prices? lol FPGA seams interesting.

[@nakul921]

@manunlimited kudos, well done, would u pls touch upon how touchprobe value, macros, and program interrelated.I tq in advance for your inputs on my questionnaires

[@AtManUnlimitedMachining]

Yes, already plan on making those videos, just will take some time to get there.

[@davenewland776]

Hi, I just started looking at your channel - lots of great stuff here! You worked on this a while back so maybe this is not relevant now. I think the data stream looks like a self clocking code like Manchester. If so, you can keep the receiver clock in sync with a PLL. The transmit data is mixed with the clock with an exclusive or gate. I don't remember how to reverse that to receive but the info is available.

[@AtManUnlimitedMachining]

You could, but it is not really needed. You can resync with every start bit and stay in sync for the length of the packet. Not a big deal with today's clocks.

[@dsteele57]

Very thorough work here! "Deep dive" may be an understatement but it's really worth watching all the way through. Am I right in saying that all that is required to start the probe is a 2kHz IR burst? Also, do you know if the IR pulses coming from the MP10 are identical to the OMM's signal output (with some amplification and filtering on the way)? Thanks

[@AtManUnlimitedMachining]

Yes, I think it changed the freqency and the time it is sent to increase range though. I can look at what I'm using now. The OMM start is just straight up pulses. The signal from the MP10 is a digital bit stream. But they both use the same IR range as the OMM picks up its own start signal as well.

[@smgvbest]

Really enjoyed this deep dive and your other video on the MP10 teardown(rebuild). One question i have is how in depth did you look at the actual IR signal so that one could build their own OMM instead? I have a MP10 from ebay myself but only the MP10 and can't see to spending the 600 for the OMM for my use (hobby/tinkering). I have a decent lab I can probably decode it but if you have any doc you'd be willing to share I'd love the details.

[@AtManUnlimitedMachining]

The OMM does not provide any decoding, it is just signal conditioning of the IR to a square wave. The actual light emitted matches the data from the OMM. This is only true for older probes or new probes in legacy mode. To decode the signal you need to make a custom serial receiver. The bit timing is a little strange because of the optimum sampling timing. I use an FPGA to do this.

[@smgvbest]

Oh ok, I just re-watched and totally missed that point. Effectively the OMM then is a IR to RS422 converter. I guess the signal strength is really just based on the intensity of the IR signal thru a OP AMP compared to some reference level which was the upper right circuit. if I'm going to roll my own circuit I think I would make the signal strength and start separate lines (I don't' need MI-12 compatibility) just need to read the probe really and to send it the start signal. need to order some IR parts to start playing around. I'll most likely do this in a CLPD (i'm partial to Coolrunner II's) but who knows what it will be in the end.

[@AtManUnlimitedMachining]

Correct, more or less it acts like an IR to RS422 converter. Yes, I would separate the lines if I was rolling one. Signal strength can just be an analog line, or you can put a ADC right at the op amp off the IR receiver. I started to make an OMM from scratch. It is relatively simple. I just used a few op amps. First stage had a gain and offset so output was between zero and 5V when the IR went from dark to saturated. Then you can take that line and put it into another amp with a low pass filter for the signal strength. Then take the same signal off the first amp, put it through a high pass filter followed by a very high gain amp running on a single 5V rail. This will give a nice output level for the input to your processor. A CLPD should work fine. The timing I ended up with, wait 1.25uS after seeing the start bit transition, then read the line for the first byte. Then I wait 8.025 uS between each byte. I used a 40 MHz sampling rate. I think it should be 8uS but my probe seemed a little slower and I aligned the timing to it. To turn on the probe I ended up with a pulse frequency of 8KHz with 50% duty cycle for 1 second for it to be 100% stable. Each byte has a compliment byte, I check those and if any don't agree I send a "touched" command to the CNC so it stops. The probe should transmit every 16 mS or if there is a touch when its on. I added a 20 mS time out where I trigger "touched" as well. That way if the probe turns off or gets blocked the machine stops motion.

[@smgvbest]

Just got a OMM off ebay cheap, wasn't planning on getting one but did. I had to clean it up considerably but it seems to be working fine. I hooked up 10V to the unit via a 9v bat and a boost converter to get it to 10V. hook up my signal generator set for 2Khz @ 10Vpp and it started my probe fine. hooked up Signal 1 to to the Rigol and got a good signal out. I'd attach waveforms but this isn't a forum lol. i did check and i see the spacing puts things at ~120Khz on my scope based on difference between pulses out. I took some screen caps off the scope if your interested. allot of work to do but but it's a start

[@AtManUnlimitedMachining]

It is not that bad, I had it decoded in a few hours and cleaned up and ready to go after another few hours. Just leverage some UART code and mod it for the different start bit time and your done ;)

[@CalvinoBear]

I wanted to bounce something off of you. For background, I'm working on a small C-frame mill (work area of about 6x9 inches) and am thinking about spindle motor specs. The largest tool that this thing will reasonable run is probably somewhere around 1/4" (maybe in steel; mostly in aluminum and plastics). I plan to make my own spindle using an ER collet holder and preloaded taper roller bearings, as others have done. Am I right in thinking that these small cutting sizes require much less actual cutting power, and that the important aspect is how the cut is controlled? As far as power goes, it seems like size limitations keep me to about 500 watts. I know that the cheap Chinese spindle motors can't handle steels because of their high velocity and low torque, as well as lack of feedback control, so it seems like the best option would be to acquire a more torque dense motor and drive it properly with a real servo drive that can accurately control its velocity in cut. I really don't think the solution is to add horsepower (as many others have done) if you're not going to use large tools (face mills). Having watched real machining centers that have real time cut power monitoring, small tool milling of even alloy steels seems to take very little power (somewhere around 1-200 watts), and the key is to control the motor well and have a rigid setup. Is my line of thinking here reasonable? Thanks for your help.

[@CalvinoBear]

I love your channel by the way, it's elucidated a lot of things about CNC machining and CNC machines that were obscure to me for a long time.

[@CalvinoBear]

Also would you happen to know Danny Diaz from NI? It's a long shot, but I believe he was a lead systems architect for NI that developed a great deal of LabVIEW's real time functionality.

[@AtManUnlimitedMachining]

Hello Calvin, the biggest issues with most of these small home built cnc machines is rigidity. They don't have a lot of mass and there structures flex like wet noodles. That is why you see such horrible surface finishes. Combine that with cheap linear bearings that have no preload on them and your stuck cutting plastic. Make the thing as heavy and as rigid as possible, watch your preloads. For the spindle, yes you must have good control. Routers are not designed to cut metal. Most of the home spindles are to high of RPM. Unless your using really small cutters in only aluminum there is no reason to go 20,000 RPM. I would say 5000 RPM is a good number for the upper end unless you plan to use really tiny tooling. You also need torque to cut metal. That is where your power comes in, you need X torque at X RPM that equals horsepower. You can easily put more the 1 HP into a 1/4" endmill. It all depends how fast you want to go. It is all about maintaining a chip load, that is most important. Typically if you fall under 0.001" chip load per tooth the tool starts rubbing and you burn it up. If you spindle slows down in the cut and the chip load goes up to high you will break the tool. I would not go less then about 1 HP for a spindle. Make sure to check the torque curves for the motor. Hope that helps and good luck! Thanks for watching the channel. No, I don't think I met Danny, but I go down to Austin at least once a year and work with NI a lot.

[@CalvinoBear]

Tim, thanks for the reply, it has helped a lot and soothed my conscious a bit. I'll come back and ask if I have questions. Danny is not at NI anymore but I wanted to ask, as he was one of my mentors on a high school robotics team and what he did seems to be hand in hand with what you do. Cheers, and thanks again!

[@AtManUnlimitedMachining]

Your Welcome Calvin, thank you for the support! Feel free to send an email if you would like.

[@Steve_Just_Steve]

Tim, great vid! Most of it was way over my head, but still very interesting. Do you already have the Fadal boards necessary for 2 probes? I thought there was an extra board that was needed to run both spindle and tool probes. Is that correct? That's awesome you've been working Autodesk on the Fadal post! I think Fusion has probing posts for some machines, hope they add to Fadal soon! Edit: Just heard your going to -5 card, that's sweet! Can't wait for the install vids and hopefully macro vids at some point!

[@AtManUnlimitedMachining]

He Steve, I figured out how to wire the probe in without any additional cards. You can used either the Fadal board or Renishaw boards with an external power supply normally. Yes, there will be a video with a card upgrade at some point to -5 cpu board.

[@HybridiHippo]

You hav been busy...

[@AtManUnlimitedMachining]

Extremely!

[@AlexKubrinsky]

Thanks! Very useful info, sub.

[@AtManUnlimitedMachining]

Your welcome

[@jasongallahair2418]

looks good