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I have a machine to retrofit. Seems pretty straight forward (famous last words)
Drives are good, spindle is good, control is shot.

drives are some type of analog input (0-10, +-5,something)
encoder feedback is all differatial (+a-a, +b-b, +z-z)
lots of I/O
I have on hand a 5i25 and a 7i77. Will this get me there to talk to 4 analog drives and read 4 encoders? will it leave me with lots of I/O?
need to get the tool changer working as well.
If I need more/other boards I am happy to buy them.

In my dream world this would be connect the signals and everything works after proper configuration. meaning the hardware is not the issue.8

Michael wrote:

It's great he sent you a picture of a 1ms delay. But he told me the same thing. And when I asked why it's 5ms he could only point fingers at Linuxcnc but couldn't articulate any particular thing to look at that caused the delay.

 

You can't either because it's not "5ms". Using the HAL analog output command as your starting reference is not the right way to do that because nobody knows what voltage you have the drive set to respond to. At best the 3ms delay between encoders is valid.

Plenty of other setups use Linuxcnc and a 7i77 board but don't have this issue. I couldn't find a single example of someone using DMM with accurate encoder feedback. The only ones I found were using galil controllers and they used filters to remove the delays they were getting back from the encoder section. 

I use a DYN4 with encoder feedback and it's plenty accurate. I use a 5000k rpm motor on my spindle controlled with step/direction from a 7i76e, it rigid taps all day. Analog control shouldn't make a difference except what is calculated as the deadzone. The analog command doesn't have an effect until the voltage is above/below the deadzone which is why you can't use the first blip of your HAL analog output command as a reference. If there was no deadzone you wouldn't be able to stop the motor but nothing about that is unique to DMM.

And regardless of using a scope or not the servos would over current fault attempting to catch up to their commanded speed .I could never get them to run full speed in velocity mode with a closed loop.

Again sounds like you didn't tune the deadzone out of your PID. I'm assuming that because A, that's exactly what would happen as the drive just reached the Analog input threshold and B you never mentioned the deadzone then you posted the halscope image and the only way you come up with 5ms from looking at that is if you don't account for the deadzone at all. The size of the deadzone is dependant on other parameters set in the drive, it's on P78 of the manual

You have to ask yourself "why is no one else having the same issue running Linuxcnc and servos in closed loop". Maybe the issue is with DMM servos not being well built. 

Well built compared to what? Are you expecting a $250 servo drive to be as good as a $1k drive? If the "issue" is the "delay" then we gotta figure out what the actual delay is and if it's unreasonable. I have a DYN4 setup on a motor stand coupled with an encoder so I can test this. I didn't feel like setting up a Windows VM last night to re-configure the drive but I'll do that at some point today maybe. Like I said, I would expect a "delay" on the encoder output because of the nature of how it's generated. 3ms seems excessive, 1ms is probably fine but realistically it has to be compared with other drives doing the same thing.
 

Thank you for your feedback,

to check the encoder connection i dismantled it until i could see the wiring on the connector, below is the wiring for the encoder output connector

  
I have the impression that the 3 channels A,B,Z are single-ended, can you confirm this?

Between the connector and the encoder there is an electronic card with the following outputs

V+ - RED
G   - BLACK
V-   - BLUE
CG - GREY
G    - YELLOW
B0   - WHITE
A0   - GREEN

if this is true, the encoder wiring on the 7i77 should look like this?
 

Hello,
Following a misunderstanding of the freqrol drive and its configuration, I would like to exchange it for a more recent generation variable speed drive.
But I would like to keep its servo control.
The freqrol documentation mentions a P.L.G. spindle encoder.
Does anyone know what P.L.G corresponds to?

Does the PLG connection (below) correspond to a standard incremental encoder connection? A+/A-/B+/B-/Z+/Z-/5V
/GND
If yes, what do I wire Z+/Z- for?

1-PA
2-RA
3-PB
4-RB
5-AGA
6-NI5C
7-PZ
8-PI5C
9-AGA

the plg will be connected to a 7i77 card

Hopefully this is following the forum rules when i open a new post.
This is more or less a follow up of a post from Randy: 
forum.linuxcnc.org/27-driver-boards/3649...t-of-precix-5x10-cnc
We got a precix 3Axis Gantry mail in our department (University of applied arts vienna), which i want to give a 2nd life as the controller was broken for years. The mill has 3 DC-Servos and a 2.2KW Colombo Spindle  
I Started it in Feb. 2023. Learned a lot over the summer and set up a new controller with new electricity but mostly relying on the old components (PSU, Motors, Spindle/VFD, Drivers are original). Controller is a mesa 7i77/7i92t. 
Also learned to draw electric/electronic blueprints with KiCAD which was a great help
With the help of the forum I managed to run first G-Codes on the plain setup board (disconnected from the machine ) last week.
While tuning the motordrivers i ran into issues constantly tripping the breakers in front of the servo psu which is a beefy toroidal transformer(1500VA). Tripping happens when turning off! the PSU 1 out of 3 times. Also my ssr was blown already - maybe not a good idea i found out already.
So here is my question:
Who has more experience with induction/overvoltage issues running an old psu?
Suggestions for improving the electrical layout is appreciated, as the machine will hopefully run in an university environment again and i am not a trained electrician #safety.
I also attached some images and a schematic of my current controller setup.

Thx,
Armin