Mesa 7i96 Ethernet board

More
09 Mar 2019 15:52 #128171 by PCW
Replied by PCW on topic Mesa 7i96 Ethernet board
1. Yes, you can use a USB WIFI or USB Ethernet dongle to get general network connectivity.
2. You can use a wider range of host computers, though its still much easier to use x86 vs ARM SBCs
The following user(s) said Thank You: persei8

Please Log in or Create an account to join the conversation.

More
14 Mar 2019 11:21 #128571 by ikkuh
Replied by ikkuh on topic Mesa 7i96 Ethernet board
Yes, it works great. I use a cheap USB dongle, www.aliexpress.com/item/5dBi-Wi-fi-Anten...1.0.0.27424c4dHlLlrT and it works great.
You will need two networks on your machine, a private one for the 7i96 and another one for your Wifi connections. Debian handles most stuff for you.

Please Log in or Create an account to join the conversation.

More
18 Mar 2019 12:45 #128890 by microsprintbuilder
Can you use two 7i96 boards at the same time with a dual Ethernet ports on one pc? I'm retrofiting a wire edm machine an want to use one to drive the axis which uses two axis and use the other to control the pulse power supply (5 mossfets in sync) so I need 5 step signals for that as well one encoder to read the mesa THCAD to monitor voltage and adjust the feed.

Please Log in or Create an account to join the conversation.

More
18 Mar 2019 13:04 #128892 by andypugh
Replied by andypugh on topic Mesa 7i96 Ethernet board
It should be possible to use 2x7i96.

But, the 7i96 has an expansion port for any of the "dumb" 25-pin cards, so it would be cheaper and simpler to connect a 7i78 step/dir board to the expansion port on the existing 7i96.
Alternatively you could connect a 7i76 (not -E) to the 7i96. That isn't cheaper than a 7i96 but gives you even more IO if needed.

Are you sure that a step-generator is the right thing for the Mosfet driver?
If you need a fixed pulse sequence then it might well be, and bear in mind that the Hostmot2 firmware supports table-driven step types up to 8 separate pins in a sequence 16 steps long.
linuxcnc.org/docs/2.7/html/man/man9/hostmot2.9.html#stepgen
(The table mode docs there are not very clear to me, and as I think I wrote them that probably makes them even less clear to everyone else)
You would need advice from PCW / Mesa on which daughter board would be best for such a complex step sequence. It might be the 7i85S.

Please Log in or Create an account to join the conversation.

More
18 Mar 2019 13:34 #128895 by microsprintbuilder
I need to drive the mossfets separately but in sync. Depending how much amperage i need determines how many are on. they need to be pulsed from 0 to 100khz. It was my understanding the 7i96 only supported 5 stepgens. so expanding was not a option.

Please Log in or Create an account to join the conversation.

More
18 Mar 2019 14:04 #128896 by andypugh
Replied by andypugh on topic Mesa 7i96 Ethernet board
The 7i96 has terminals and hardware for 5 stepgens, but the FPGA can handle more with the right firmware.

There is an existing firmware definition which attaches a generic 3-axis paralell port BoB to the expansion port. That might actually do all that you need, for almost no cost. (Steppers on the BoB, Mosfets on the 7i96 terminals).
It can be found in the 7i96 support file from Mesa:
www.mesanet.com/software/parallel/7i96.zip
Take a look at the 7i96_5abob.pin file to see the pin allocations of the associated 7i96_5abob.bit firmware.
There is also a 7i96_7i78 pin / bit there for adding a 7i78 to the expansion port.

Please Log in or Create an account to join the conversation.

More
18 Mar 2019 16:25 #128904 by microsprintbuilder
I'm liking the idea of adding a card but I'd rather add a 7i85S or similar if I can. Then I could have my encoder input on the card as well and just a have a single DB25 cord between cabinets. I don't need Direction pins so I could used them as steps to get 5 for the mossfets, Correct?

Please Log in or Create an account to join the conversation.

More
18 Mar 2019 16:26 #128905 by andypugh
Replied by andypugh on topic Mesa 7i96 Ethernet board
If you want encoders then yes, 7i85 sounds good.

Please Log in or Create an account to join the conversation.

More
18 Mar 2019 16:57 #128906 by microsprintbuilder
I just need one for the mesa THCAD to read the voltage at the wire to adjust the feed. Been reading up on that as well. The run in reverse thing is appealing but probably just going to adjust the feed for now.

Please Log in or Create an account to join the conversation.

More
18 Mar 2019 21:46 #128924 by tommylight
Replied by tommylight on topic Mesa 7i96 Ethernet board
Why stepgens for MosFet's ? Why not PWM as it normally should be done.
You can change the frequency of the mosfet gate but after about 100Hz it will have no difference in the output voltage up to the limit of raise/fall time of the mosfet or the gate capcitance.
In my opinion you do need PWM, or PDM but that is another subject.
I am aware that you can use very short step time and that would change the output depending on the frequency, but i do not think it will be enough. Having to short of a pulse can cause the mosfets not to open completely and overheat.
As i said somewhere, been thinking lately about doing a wire EDM, but it never crossed my mind to use stepgens for power control. That is a new one for me. :)

Please Log in or Create an account to join the conversation.

Moderators: PCWjmelson
Time to create page: 0.114 seconds
Powered by Kunena Forum