7i80 and 7i77
uli12us wrote: I have an additional question. Is it possible to connect a differential encoder to the single ended inputs of the 7i76/77 card. Or otherwise to connect the A.B_ and A_.B together on the A and B inputs of the card?
7i77 encoders are jumper-selectable as single-ended or differential.
The 7i76 has differential encoder inputs that can be configured for single-ended use.
andypugh wrote:I have it working behind me.
andypugh wrote: I have a 7i80, Let me see if I can make it work. This may take some time.
Do you still have it working, or did you already put the 7i80 back in the closet because it was buggy?
For my new mill I need more I/O, faster step generation and faster encoder counting than the humble parallel port on an Intel D525MW can provide. I also had a D525MW board break and they are becoming hard to get. New, locally sourced hardware is much worse in the latency department than the D525MW.
So I am really considering one of the Mesa cards. If only they were not so close to impossible to obtain I would already have gotten one
I would like to avoid the PCI bus if possible. The PCIe solutions are quite expensive. That leaves the 7i43 and 7i80. The 7i80 had more I/O and I really like the Ethernet connection.
I am not afraid of performing the install RT-preempt kernel / compile LinuxCNC / etc. steps mentioned, but will this result in a system that just works when I need to make a part? I do like to tinker, but I also use a mill to, uhm, do some milling from time to time.
Also, I am not really in a hurry. Building a CNC mill from scratch takes a couple of months anyway before the axes move under computer control.
I didn't find it to be especially buggy, but neither do I have any real job for it, so it went back on the shelf.
DaBit wrote: Do you still have it working, or did you already put the 7i80 back in the closet because it was buggy?
That's a pity, because I would have said that the obvious choice is probably either a 5i25 or 6i25 and a suitable daughter board.
I would like to avoid the PCI bus if possible. The PCIe solutions are quite expensive.
The 7i80 is still somewhat experimental, and typically will tie up the ethernet port (not such a problem with an internal WiFi card, I suppose).
Duzi.cz do claim to have a 7i80HD in stock,
I am not sure how good the latency/jitter is with an ethernet connection.
But even then I still like the Ethernet link. Single, small cable from (panel-)PC to control cabinet, galvanically isolated communication. One might have to add a supported Ethernet card, but Intel Pro/1000 cards are affordable and good.
I also cannot imagine much variable latency in a point-to-point 100Mbit full duplex link where only UDP packets are exchanged, but that is only from a hardware point of view. There is a lot of software in between.
DaBit wrote: But I might be able to order directly from Mesa.
Mesa have entered the 20th century and now have a web shop:
andypugh wrote: store.mesanet.com/index.php?route=produc...e=6i25&product_id=58
Postage is a killer though, $52 with USPS and $356 (!!!) with UPS.
duzi.cz: EUR 165.45 plus EUR 23,05 shipping with Czech mail = EUR 188,50.
mesanet webshop: USD 149.00 plus USD 43.75 shipping = USD 192,75 = ~EUR 145. But customs might catch the package and add VAT, import duty, etc., And then total price goes up towards the duzi.cz price.
Cannot compare the 6i25 since duzi.cz does not stock it and the other European distributor's website is offline.
But since duzi.cz is not a serious distributor in my opinion (most cards are 'sold out' for months already) the choice is not that difficult.
Can one use multiple 6i25's in one system if it turns out that i need 8 encoders and 5 step drivers?
DaBit wrote: Can one use multiple 6i25's in one system if it turns out that i need 8 encoders and 5 step drivers?
Yes. In fact you could have as many 6i25s as there are PCIe ports, as many 7i43s as there are parallel ports, as many 7i80s as you can afford routers for. At some point it would all run out of CPU at the PC end.
it might be possible to have 8 encoders and 5 step drivers all on one 6i25 though. A 7i76 + 7i77 config (the 6i25 and 5i25 have two ports, one on a header) has 5 step drivers + a spindle encoder on the 7i76 and then
The 7i77 has several real encoders and also some (onboard) MPG encoders.
I think there are 3 encoders on the (small, cheap) 7i73 board, and you can hang one of those off of the 7i76 (and most of the other DB25 cards) and 8 of them off of the 7i74 board.