7C80 + 7i74 and 7i84

More
10 Jun 2021 14:32 #211703 by jago
7C80 + 7i74 and 7i84 was created by jago
Hello,

we are working on a small gantry mill with xyz +b (table index) axis and a tool changer.
Starting with a Rpi4 and a Mesa 7C80 we have to expand the system with a 7i74 and a 7i84...

The 7C80 is running fine (after some hours of commissioning), but we need the 7i84 to access additional I/Os for the tool changer.
Now we think, that we have to load/create a *.bit file for this combo..?
Is there an easy way to create this files or does someone have a file for this combination of cards?

Kind regards, i hope someone can help us ;-)

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

More
10 Jun 2021 16:03 #211712 by PCW
Replied by PCW on topic 7C80 + 7i74 and 7i84
If you just need the one 7I84, it can connect directly to the 7C80 with out adding the 7I74.

If you need more than one SSerial channels, here is a 7C80 bitfile that has 7I74 support:

File Attachment:

File Name: 7c80_7i74d.zip
File Size:110 KB
Attachments:

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

More
11 Jun 2021 06:29 #211777 by jago
Replied by jago on topic 7C80 + 7i74 and 7i84
Great - the idea is, to use the other serial channels of the 7i74 for encoder feedback. We want to connect additional SSI/BISS multiturn absolute encoders for all axis. Is there anything special we have to look for, before ordering the encoders?

17bit absolute with 12bit multiturn 10-30VDC SSI/BISS would be the product of choice...

Thanks a lot, for your quick and reply and the bitfile ;-)

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

More
11 Jun 2021 12:40 #211801 by PCW
Replied by PCW on topic 7C80 + 7i74 and 7i84
OK if you need SSI or BISS encoders, that needs a different bitfile

How many channels do you need?

I would suggest SSI if you need many channels because it uses less FPGA resources

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

More
11 Jun 2021 14:06 #211805 by PCW
Replied by PCW on topic 7C80 + 7i74 and 7i84
7C80 configuration with 8 SSI channels on 7I74:

File Attachment:

File Name: 7c80_7i74ssid.zip
File Size:117 KB
Attachments:
The following user(s) said Thank You: andypugh

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

More
22 Jun 2021 07:04 #212647 by jago
Replied by jago on topic 7C80 + 7i74 and 7i84
Thank you very much - I think we are going to use 5 channels in the near future.

Actually we have some problems with the voltage regulation on the 7C80 for the rpi4 - the 5.03Vdc seems to be to low, to power the rpi4. The connector TB15 can probably solve this issue, but there is no documentation how it is ment to be used ;-)

Is it possible to connect an external power supply with 5.2Vdc to this connector? Is there a jumper to disconnect the internal regulator?

Kind regards

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

More
22 Jun 2021 14:07 - 22 Jun 2021 14:23 #212678 by PCW
Replied by PCW on topic 7C80 + 7i74 and 7i84
No, its meant to be an output, What is the 5V rail voltage at the RPI?
Are you uses a short cable flat cable (1.25 inches is standard)?

You could probably get away with supplying 5.2V at TB15 because the local regulator
will just shut down if the output voltage is above its setpoint, but this also means
you are supplying 5.2V to every 5V device on the 7C80 card. I would check cabling
and the voltage at the RPI4 first.
Last edit: 22 Jun 2021 14:23 by PCW.

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

More
23 Jun 2021 07:50 #212722 by jago
Replied by jago on topic 7C80 + 7i74 and 7i84
we have checked the cabling - we use a very short 40pin cable (length < 30mm) - the rpi is directly mounted to the motherboard...

The 5V line is at 5.03VDC - all over the board - the rpi4 voltage (measured on the 40 pin header) is 4.95VDC.
We think, that it might be a better way, to disconnect the rpi4 from the internal 5V source (GND should stay) and power it separately, instead of pushing 5.2V to the mesa card. It is a pity, that the rpi4 needs a higher voltage than 5V to operate safely...

We are also searching for a failure of one "ISL32174 EIBZ" - we lost this part of the mesa card on stepgen2/3, while commissioning the servos. We use inverters from cs-lab (simdrive 400W) with standard differential ttl optocoupler inputs... we have checked the cabling several times, have done an analysis with differential probes on all lines (see screenshot) and we can not find any "physical" problem. Perhaps you have a clue...
Attachments:

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

More
23 Jun 2021 13:33 #212741 by PCW
Replied by PCW on topic 7C80 + 7i74 and 7i84
It actually sounds a bit like a defective RPI4, At least I have never seen this issue
or heard of it from another customer, and have at least a year of uptime on my test system.

If the step/dir outputs do not swing a full 5V when unloaded, the driver chip has been damaged. This can occur if the outputs accidentally contact something with a voltage outside the 0 to 5V range. A max3042 is a replacement (ISL32174s are hard to find currently)

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

More
23 Jun 2021 14:57 #212750 by jago
Replied by jago on topic 7C80 + 7i74 and 7i84
ok - we will replace the rpi4 and see what happens ;-)
The idea with the external power supply will be tested, if the under voltage message is still there, after the replacement...

Thanks for the max3042 clue - the ISL32174 is available in 2022...
Do you have a number for the version with 3.9mm width..?

Kind regards,

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

Moderators: PCWjmelson
Time to create page: 0.111 seconds
Powered by Kunena Forum