One more HURCO BMC 20P Retrofit

Greetings to Everyone!

I have been reading and examining the LinuxCnC community for quite some years now. Almost five years ago (when my knowledge on electronics/programming was fairly limited) I have decided and made from scratch a 3-axis CnC machine using Mach3. Now, after some fails and successes, and having become an owner of a Hurco BMC 20P (for the past 8 months), I believe the time has come to start reverting everything to LinuxCnC rather than trying to upgrade more “closed” systems/software as mach3 or reusing them to another machine.

I have seen some excellent posts with ideas/files/photos about retrofitting the Hurco BMC 20 (from tommylight, bruno2626, and many others) and decided that I have to give it a go! The machine currently is in a working state but its old electronics (mid ’90) are keep reminding me their age and giving me a hard time trying to solve errors codes (which nobody knows anything about them), replace parts which are very difficult to find (and with unbelievable long lead times) and load cutting programs to start making some metal chips (only by a serial cable or with a floppy disk…)

So, in plain words, I’m prepared to get really busy the coming months, give life again to this machine, and any help will be honestly and greatly appreciated!

Apologies in advance if in the process of this retrofit I become an “askhole” but sometimes I’m interested learning “why” doing something rather than “how” to do it.

 At the moment my Hurco BMC 20P has the following features/modules
Servo Drivers: Yaskawa servopacks CARC-SR10BB1BF.
Servo Motors: Yaskawa USAFED -09FB1S with UTOPI-500UA Encoders.
Spindle Drive: Yaskawa CIMR-MT III – 7.5K (Transistor Inverter)
Tool changer: 16 Tools, Carousel type (two pneumatic pistons for up/down/left/right and one AC motor for rotation)

The machine has all its original documents including wiring diagrams which is always a good starting point

Some photos are attached, some parts are removed since we have entered the cleaning/modifying/replacing process.

Some initial questions before start gathering all necessary hardware…
Query 1: HAL
I have been examining to use the following Mesa Cards for connecting everything as previous retrofits had. But I’m not really sure where (and why) everything should be connected.

For example: PC with Ethernet -> 7i92M
7i92M==> Connection B-> 7i77ISOL in a 7i77 (sourcing output version). Connection A-> connects with RS422 in a 7i74.
7i77-> Input and output for Motor Encoders, Servopacks (servo drives), Spindle Drive.
7i74 -> Connecting with RJ45 to 7i70, connecting with RJ45 to 7i71.
7i70-> Connect receiving signal from limit switches from Carousel Tool changer (up, down, left right), receiving signal from limit switches from moving table (X-+,Y-+) and moving column (Z-+)
7i71 -> Connect to coolant pump, connect tool changer turning motor.

As far as I understand, input and outputs may not start and finish on the same card. For instance, which of above cards should be used to activate the solenoids controlling the pneumatic movement of the tool changer or the tool spindle? (I would say the 7i71 but I’m not really sure). Maybe it’s a childish question, but coming from Mach3 (where everything was connected to a single controller card and a single button did the trick), I’m having trouble identifying which cards should “give the command” and which cards “confirm that the command was executed” to move on.

Query 2: Pedant
I have seen that it might be possible to use the Hurco’s Pedant control to the LinuxCnC, will a 7i73 mesa card connected directly to the 7i74 work?
If yes, how the rest of the signals (like position marking, spindle speed) will have to be connected through this card? Will I have to use an extra card to perform these operations? (Something like 7i84D)

In the case that these questions have already been answered before, please point me the way, any additional info is always welcomed.

Regards
Christos

Hello guys!
First of all, Tommylight I wish I had your confidence! . This will be my first machine with LinuxCnC so everything is a mess in my head right now. I have already looked on your configs and Andy is right, I have to write down all the I/O with voltages to see what should go where...

Just a quick note, I have read about these drivers (Yaskawa), and seen that sometimes they die in the process. I was thinking that if something like that happens, and since the machine has open-end-ballscrews to connect any new encoders to the opposite side of the ballscrew, theoretically this will work and since I have seen how tight these encoders are to the shafts (out of curiosity I have opened the Y-axis motor) this might be the only solution, lets hope that it will now come that way...

Being eager to start, I have already ordered the Mesa electronics (will provide a list later on), just to try to save some weeks or so (payments/delivery), it wasn't the best thing to do, since I haven't completed my "logical" diagram of what should of where but this will "mentally" convince me to get things rolling. Will share with you some of the ideas as soon as these are in a readable state...

I have checked again the configs/hal on Tommylight post, I think these were not the final ones or not everything was connected in the end (I might be wrong, but I have a lot of alarm/limit switches that should be connected)

By the way, if anyone is in need for the electronics/schematics and general documents of this machine, I have already made most of them in pdf, for when the troubleshooting starts .

Will revert as soon as I have some schematics ready, any suggestions which software to use to make some?

just grab Adobe scaner from the APP store and scan them with your phone to PDF and post them here, I know for sure I need a set of these schematics. Particularly for the tool changer !

It’s time to get our hands dirty, PC and cards are here.
And at the same time, realized that I still have more questions than answers...

Question A.
The PC is a HP-8200 (I3/4Gb/250SSD/DVD), loading live LinuxCnC from a (pretty old) usb stick got a 65K on Max Jitter (ns) on the Servo thread (1ms), I have to confess that I have tried to open up everything that I could (youtube 4K, glxgearsX3, browsing wallpapers) which in normal operation nothing like this will ever happen . I still haven’t cleared all things in BIOS, not installed anything on the SSD, but I’m not really sure if this PC will actually work on this. I’m a bit confused of what should be my Max Jitter when it comes to control servos? Is there a specific number that I should be looking to be lower than?

Question B.
The PC will be about 4m far away from the 7i92m, the 7i77 will connect directly to the 7i92m (Ethernet). Placing a 7i77Isol in between them will have any effect? (Don’t know why but I had one ordered before asking this question and wondering whether I should use it or not)

Question C.
As my biggest concerns are the encoders, I forgot the list of the i/o and started with them… At the existing machine the “control relay panel” has 3 connectors (X,Y, and Z) “From encoders”, opened up one and found 7 cables… (I could say without really knowing that 6 cables are A/A, B/B, Z/Z, what is the 7th?) I’m trying to figure out which ones I have to connect to the 7i77, any help is appreciated, photos are attached (wiring diagram, connector photo).Edit:… Rewriting my query, I’m most probably missing combined information how servos are controlled through the 7i77, or how the “loop” is controlled and closed with or within the Yaskawa servopacks…

Beware that coming from a stepper motor system, still trying to close the loop in my head first how things should be working… Reading around, I have seen that there are several “modes” for configuring the machine, most probably I should be looking to get “velocity mode” instead of “position mode” but don’t know their differences (also there is “torque mode”?). Could someone point me to a direction where to look?

@smc.collins -> All diagrams have been scanned, unfortunately my phone wasn’t doing the job right, so scanned everything from photos. Let me know how I could post/send them to you (due to size of these drawings and for being able to read them total pdf size is about 240Mb).

email is best. smc dot collins1977 at gmail