Mesa 7i76E+7i77 how to make work together?

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27 Nov 2019 07:23 - 27 Nov 2019 07:30 #151338 by Fallountam
Good time!


I am building a 3.5 axis machine for wood processing. To drive the axes, Chinese-made servos are used, which perceive step and direction signals, but have encoder outputs for the CNC system. I would like to have feedback on the axis, but the 76E board does not work like that. On the shelf in the workshop there was a 7i77 board, which theoretically can help me read encoders. I made a connecting cable for them.
As I understand it, I need to flash the 7i76E board to work with 77. How to do this? PnCConf
Please tell me where to look and what to read on this topic. I'm just starting to study the Mesa boards and their settings

Thanks!
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Last edit: 27 Nov 2019 07:30 by Fallountam.

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27 Nov 2019 13:41 #151345 by bevins
Why are you not using +-10v analog velocity control for those servos? Usually the chineese drives can do +-10v. then you just take encoder directlyu in the 7i77.

Use mesa flash for changing the firmware.
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27 Nov 2019 13:47 #151346 by Fallountam
When these boards start working together, the servo control method will not be so important. The pulse method does not seem more resistant to possible interference.

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27 Nov 2019 14:29 #151351 by tommylight
Get the support files from mesanet.com for the 7i76e, unzip them, find one that has 7i76e and 7i77 in the name with the .bin extension, open a terminal and type
mesaflash --device 7i76e --addr 10.10.10.10 --write name_of_the_bit_file.bit
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27 Nov 2019 15:28 #151355 by bevins

When these boards start working together, the servo control method will not be so important. The pulse method does not seem more resistant to possible interference.


Yes but you dont have the added advantage of FeedForward in the loop, among other advantages.
If you have the capability of velocity control why not use it?It is easier to setup in HAL also. There is the tuning aspect though.

just my thoughts.
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27 Nov 2019 16:31 #151359 by Todd Zuercher
Actually not true. With a closed loop setup the stepgens are controlled with a velocity command and a PID loop and tuned exactly the same way as an ordinary analog velocity command servo and have the same feed forward capabilities.

There are more inexpensive options to add encoder feedback to your 7i76e than a 7i77, such as a 7i85 or 7i89. (I understand that the 7i77 may have been at hand, but you may want it for a different project down the road.)
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27 Nov 2019 16:57 #151367 by bevins

Actually not true. With a closed loop setup the stepgens are controlled with a velocity command and a PID loop and tuned exactly the same way as an ordinary analog velocity command servo and have the same feed forward capabilities.

There are more inexpensive options to add encoder feedback to your 7i76e than a 7i77, such as a 7i85 or 7i89. (I understand that the 7i77 may have been at hand, but you may want it for a different project down the road.)


I didnt know that... Thanks
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27 Nov 2019 17:12 - 27 Nov 2019 17:17 #151368 by Fallountam
Friends, thank you very much for your comments, now there is light at the end of the tunnel.

I use 7i77 just because it already exists. I thought about 7i85, but I have no way to purchase this board in a reasonable amount of time. I am in Russia, and the local mesa dealers do not have a very large assortment.

A few years ago, I already made a small machine on the old Aerotech BA20 analog servos and boards 5i25 and 7i77. Then it did not seem difficult to me, most of the settings were available directly in PnCConf.
Last edit: 27 Nov 2019 17:17 by Fallountam.

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29 Nov 2019 11:09 - 29 Nov 2019 11:18 #151489 by Fallountam
I will ask for help again. I executed the command in mesaflash, but after its successful execution in pncconf no new firmware options appeared to choose from.

user1@linuxcnc:~$ mesaflash --device 7i76e --addr 192.168.1.121 --write 7i76e_7i76x1_7i77x1D.bit
Checking file... OK
File type: BIT file
Boot sector OK
EEPROM sectors to write: 8, max sectors in area: 16
Erasing EEPROM sectors starting from 0x100000...
|EEEEEEEE
Programming EEPROM sectors starting from 0x100000...
|WWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW
Board configuration updated successfully.
Checking file... OK
File type: BIT file
Boot sector OK
Verifying EEPROM sectors starting from 0x100000...
|VVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVV
Board configuration verified successfully.



user1@linuxcnc:~$ mesaflash --device 7i76e --sserial
SSLBP port 0:
SSLBP Version: 1.43
SSLBP Channels: 5
SSLBP Baud Rate: 2500000
sserial device at channel 0: 7I76 (unit 0x1A000392)
SwRevision = 14
HwRevision = 1
NVBaudRate = 2.5Mb
NVUnitNumber = 0x1A000392
NVWatchDogTimeout = 50ms
SOFTWARE MODE IO_Spin [index 00]
SOFTWARE MODE IO_Ana_Spin [index 01]
SOFTWARE MODE IO_Enc_Ana_Spin_FV [index 02]

as I understand it, in these lines only information on board 76 is indicated?
Last edit: 29 Nov 2019 11:18 by Fallountam.

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29 Nov 2019 17:28 - 29 Nov 2019 17:30 #151511 by PCW
A couple of things

1. After you flash a FPGA card, you must either power cycle the card or use mesaflashes --reload option:

mesaflash --device 7i76e --addr 192.168.1.121 --reload

(this loads the FPGA with the newly updated flash memory image)

2. I'm not sure how much the --sserial option reports but you should see the new pinout with:
mesaflash --device 7i76e --addr 192.168.1.121 --readhmid
Last edit: 29 Nov 2019 17:30 by PCW.

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