Thanks for the information.
I`m sure there are some facilities, but it`s probably only worth it, if your device costs several hundred dollars or is not available anymore. Google told me that simple repairs start from 120$ and more. A bit too much, unless I can be 100% sure that it works afterwards.

I`d love to send it to Mesa directly, but last time i wanted to order two cards, the shipping calculator presented me with a 250$ shipping fee. Todayy it`s 98$, but import taxes and tolls allways work in mysterious ways according to my experiences, so I refuse.

If nothing works, I can still use it as a huge I/O expander with a second ethernet port. I saw a video on youtube, where they connected two ethernet cards to the host with an ethernet switch. I think i read that one should avoid switches in favor of a direct connection, but my Raspberry only has one ethernet port. I will probably try it, if i order a new 7i76eu.

Anyway, thanks for the help.

Dear Linuxcnc forum members,
Since this is my first use of the forum, I would like to start with thanking the community in providing this very nice software and all the support around it. I am trying to equip an old (1980) MAHO 300 NC machine with complete new servo's, wiring and of course Linuxcnc. For this purpose I procured a MESA 7i76e card and several MESA sserial daughter cards (1x 7i85 2x7i84, 1x 7i87).

I installed Linuxcnc a while ago (version 2.9.4), established the ethernet connection with the 7i76e and installed 7i76e_7i76x1_7i851D.bit file using the mesaflash tool on the 7i76e card itself. I think that this went well, see attached response on on a --readhmid command. I also made the 3 RJ45 connection cables which fit between the 7i85 and the individual sserial daughter cards (1x 7i84, 1x 7i84U & 1x 7i87). I also conclude that these cables are correctly assembled, as I do see the name of the daughter card and pins in a first machine configuration I made for the machine using pncconf. However.... They only work on one of the 7i85 sserial channels, namely the one identified in the MESA manual with Serial 4. None of the cards are visible when I plug these in in the other Serial connections on the 7i85. In pncconf I also encountered the "issue" (not sure if it is an issue or intended functionality...) that I could only select 7i76e_7i76x1_Dpl, where I had expected to also find something similar to the name of the 7i76e_7i76x1_7i851D.bit file. When I run --serial in mesaflash I also see that there is only 1 sserial  channel available, namely channel 6 (see second attachment). This while I had expected to find 6 channels in total (1 on the 7i76e and 5 on the mesa 7i85). During my own attempts to solve this I also changed the hal file line which refers to hm2_eth  to:loadrt hm2_eth board_ip="10.10.10.10" config="num_encoders=5 num_pwmgens=0 num_stepgens=5 sserial_port_0=00000000"Unfortunately this still doesn't allow me to connect a second sserial daughter card to any of the other sserial positions on the 7i85 other than Serial 4. Since I am stuck on this already for a while I decided to write this post in the hope that somebody is willing to help me out with some advice on how to proceed. Some specific questions:-What do need to do on the linuxcnc PC to correctly install the bit-file “7i76e_7i76x1_7i851D.bit”? I do see some info on this topic on: www.linuxcnc.org/docs/html/drivers/hostmot2.html but I lack experience to perform the right steps to do this install using the Synaptic Package Manager. I only have the zip file from MESA with the *.bin and *.bit files in them but don’t see this in the Synaptic Package Manager.
I also browsed to the " -Do I need to occupy the sserial on the 7i76e before I can put daughter cards on the sserial on the 7i85?
Many thanks in advance for your support.

The part number was in my first post = 74CBT16211CDGGR

Hi

Im based in switzerland and could give it a shot with repair by replacing U3, if i know what chip it is

Yes, 000000 Indicates the likely U3 has been damaged and is shorting out
the shared 4V supply so U20 and P2 will not work either.

I'm surprised that there is no SMT repair facility available there. We routinely repair
minor faults like this for a nominal fee ($35.00), but of course shipping is s killer.
(the part is about $1.00)
 
EDIT:
Its likely that if you simply removed U3, that the other port would work allowing
you to connect the 7I85 to P2.

The 0x1004 is simply the register address of the GPIO port that's connected  to P1.
It should be all ones = 0x0001FFFF when unconnected because the expansion
GPIO ports on a 7I76E have pullup resistors and all GPIO is set to input mode
at power up or watchdog fault. All 7I76E firmware is open source and the low level register
addresses/functions are provided in the regmap file in the source directory of the 7I76E
software support zip file.


The 7I76EU is a one-to-one replacement of the 7I76E, no hal file changes are needed,
unless you want to use one of the new features.

Thanks a lot for the fast response PCW

Both comands returned 00000000 (when lncnc is running in the background, the operation is not permitted,right?).
I take it, this means there is no response, or a faulty one. Now I can see some slight color degradation on top of U3 compared to U20, which i brushed off as dirt before. But it`s probably from the accident.

Is there anything else to test before trashing it? I don`t think anyone in Switzerland is doing PCB repairs, and if they do, a new one is probably cheaper.
Since the 7i76 is replaced by the 7i76eu, I will have to get the new one (if it`s even available atm). Is there any major change between them, or can I more or less leave the .hal file as is? I probably have to change the name everywhere, but as far as I know, the rest should be working the same way.

Thanks again for your help. I see your profile on every second post on this site and it helped me countless times before. I appreciate you taking the time to support so many people.

P.s. Is this "rpo 0x1004" something one should know, or is this more of a manufacturer inside knowledge?

You can do a quick check of the expansion port condition with:

mesaflash --device ethernet --addr IP --rpo 0x1004
for P1
and:
mesaflash --device ethernet --addr IP --rpo 0x1008
for P2

Where IP is 10.10.10.10 or 192.168.1.121 depending on 7I76E setup

Both should respond with  0001FFFF (with nothing connected)

Typically what would be damaged from this kind of a fault would
be either U3 (P1) or U20 (P2) = 74CBT16211CDGGR

P1 (U3) damage may show up on P2  (U20) as the chips share a low current
4 V power supply and a damaged chip may short this supply so the undamaged
one also shows a fault.

Hi Guys

I am currently building my first Linuxcnc powered milling machine and the problem i`m facing now led to the first forum post in my life.
I use a Mesa 7i76e and added a 7i85 for the encoders. A while ago, I have set up all the servomotors and could even get them to run with the encoder feedback (encoders only update the DRO for when i want to mill by hand, without the motors). 
Unfortunately, a live wire touched one of the two boards and a bit of magic smoke got released. I didn`t see where the smoke emerged and i don`t see any damage on either board (but the amount of smoke should indicate some visible marks). Now my Encoder counts don`t get recognized by the Mesa cards. This is my current situation:

- I watched halshow and neither rawcounts nor any other counters see anything. 
- The encoder on the 7i76e still counts correct. This let me believe, that the encoders and wiring are good.
- The .hal file should be of no concern to me, correct? Halshow shows all 5 encoders but only Enc04 on the 7i76e counts.
- I bought a new 7i85s (7i85 were not available) and the new card doesn`t count either. (I flashed the correct bitfile)
- I put the 7i85 as well as the new 7i85s on the second expansion port and neither of them counted. (I flashed the correct bitfile)
- I tried to use one of the stepgens on the 7i85s but got nothing. (Tough, this one could be on me with a wrong configuration)
- I unfortunately don`t have another ribbon cable at hand. Is it possible, that the cable got damaged? I doubt it.
- The jumpers on both cards should be set correct (to RS422, power supply via exp port) and haven`t been changed since it worked in the beginning.

My question: Is it possible to force a sign of live out of the 7i85? Or somehow get proof, that the card gets "recognized" by the 7i76e? I would like to avoid unnecessarily buying a new 7i76 since they are hard to get and pretty expensive. Can I test something with a multimeter?

I`m grateful for any thoughts or ideas. However, my knowledge about electrical circuits is pretty shallow and even worse around software stuff (I hate Linux with a passion even tough I love the idea of an alternative to Microslop).

Thanks and greetings from Switzerland

P.s. I saw another post and it seems there is a terminal comand where you can force some response or a dump of specific components on the card. But I really didn`t understand anything going on.

Did you download this through the pcnconfig or the browser?

On my VMC that I retrofit, Im running lcnc 2.8.0 (did so a few years back), using AXIS... ive had an intermittent problem of axis completely freezing while the machine continues to operate, but not able to use any keyboard input and having to estop and kill axis via taskmanager to restart the machine.
I would consider this hugely dangerous... anyone else have an issue like this?
Its been especially long programs where the toolpath display has had to remove previous run path highlights as it goes that have caused this issue.
Lcnc 2.8.0, mesa 7i76e, dell touchscreen, i5 something or other with 8gb ram. edit: running on linux mint 19.1
Stable for short parts very well, but running long programs has now got me a little scared.

Is this one of those times where an upgrade is warranted?
 

Hallo ich möchte gerne ein 5/2 Wege Magnetventil  an eine  Mesa 7i76e anschliessen.
Ich habe folgendes in meine Hal-Datei geschrieben:
net werkzeug-auf <=motion.tool-release
net werkzeug-auf => hm2_7i76e.0.5.output -00
Vedrahtung: TB5 Ausgang 00(Mesa TB5 pin 16)

Linuxcnc meldet  unbekannt  motion.tool-release
 wo ist mein Fehler

mfg 
Hilton

 

rodw wrote:

For such a large machine upgrading from the 7i96s would be a smart move as io is limited (but you can add extra boards). eg. Depending on your needs 7i76eu, 7i95t, 7i97t.

Ok, I was just thinking that buying it once for the complete machine would be easier and more clean instead of adding the various boards per needs. Also because time sometimes makes obsolete something and its difficult to
find later.

rodw wrote:

Note that if you do fall back to ethercat, with beckhoff, you just need to add an extra input or output module at any time as required at a cost of about $50 for another 8 ports.

In fact the initial idea of going with EtherCAT was exactly to prevent not having the possibility to add later
some functionalities. To me seems that more and more industrial stuff is going EtherCAT direction.

rodw wrote:

Don't forget LinuxCNC can handle about 8 spindles so the drill could get a free ride on another Z axis stage if you are creative.

ok thanks for that info. I will have to struggle a lot with it, I know

rodw wrote:

Does your table have downdraft zones?

What you exactly mean by "downdraft zones" ? I have not yet build the table where the workpiece will sit on.
But the gantry is already existing and here are some pictures of when I received it. brastrak.com.br/files/cnc/

For such a large machine upgrading from the 7i96s would be a smart move as io is limited (but you can add extra boards). eg. Depending on your needs 7i76eu, 7i95t, 7i97t.

Note that if you do fall back to ethercat, with beckhoff, you just need to add an extra input or output module at any time as required at a cost of about $50 for another 8 ports.

Don't forget LinuxCNC can handle about 8 spindles so the drill could get a free ride on another Z axis stage if you are creative.

Does your table have downdraft zones?

Nomenclature nitpick: Unless you've got encoders on there, those are stepper motors, not servos. And even steppers + encoders are typically referred to as "closed-loop steppers", not servos.


PSU: If you're going to use a switch-mode PSU, make sure you get a big (uF rating, voltage rating) capacitor to put on it. Motors dump energy into the PSU on deceleration, which can lead to voltage spikes and blown stepper drives and/or PSU. A toroidal/transformer based supply is often recommended instead for this reason.

This may also be useful: www.geckodrive.com/support/power-supply-basics/


Wire: You may want multi-conductor wire. If that's for the steppers, 4-conductor would be good. Running 4 separate wires to each motor seems unnecessarily obnoxious.


Missing from your list: buttons, switches, fans, terminal blocks, enclosure, mounting hardware, connectors. Specifically, you'll probably want to put your parts in a box of some kind, and at the very least an e-stop is a good idea. Generally you want that wired such that it hard-cuts power to the motors+spindle of the machine or otherwise renders it in a safe state.

Drawing out everything you'll use and the connections between them can help identify gaps- eg, making sure you have enough terminal blocks. It's shockingly easy to run out of those. Ditto for enclosure space- a little planning goes a long way there, and also getting a bigger enclosure than you think you need.


Finally: I'm not familiar with all the mesa offerings (I've got a 7i76e on my mill, IIRC), but try to think about what you might want in the future and then you can decide whether it's worth buying something with spare I/Os to support it now or accepting you may need to upgrade the card later to add things. Things you might consider:

-Coolant/air blast control
-MPG
-Spindle encoder
-Touch probe
-Toolsetter
-Hardware feed hold/single-step/pause/resume/etc. buttons
-Rotary axis

IIRC you've got a Taig, and IIRC those use ER collets or equivalent... my experience is re-zeroing tools with ER collets gets old fast. I more than once trashed a tool and/or workpiece forgetting to do so... a toolsetter IMO would be worth planning for.