ABS Encoder Posital 7i92T bit file help

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16 Aug 2023 23:46 #278215 by PCW
For just analog + enables a 7I83 is a good choice

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17 Aug 2023 15:16 #278270 by Doug Crews
Hi Peter, am I seeing this right? 7i92T P2 DB25 out to a 7i74 cat5 out to a 7i83.

The 7i74 has eight transmit -receive channels. One would be used by the 7i83 the rest for abs encoders. SSI needs data and clock signals. Would I get both data and clock with the remaining channels i.e. 7 abs encodes?

And to double up I would use P1 on 7i92T out to another 7i74 – 7i83

-Doug

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17 Aug 2023 15:44 #278272 by PCW
Yes, a 7I74 provides 8 RS-422 channels, these can be
absolute encoder channels, sserial channels, etc
 

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17 Aug 2023 16:53 #278277 by Doug Crews
Wow, my head is spinning with the possibilities. I really need to get good at SSerial.

I ordered a 7i74 and a 7i83 should be in my hands tomorrow late afternoon.

Do i need to do anymore for you on pinouts? I'm thinking just mimic 7i77.

Thank you
-Doug

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17 Aug 2023 18:30 - 17 Aug 2023 19:43 #278291 by PCW
Let me see if a 7I92T config with two 7I74s (say 6 SSI + 2 SSerial each) fits

Edit, easily:

 

File Attachment:

File Name: 7i92t_ssix...sx4d.zip
File Size:294 KB


 
Attachments:
Last edit: 17 Aug 2023 19:43 by PCW.

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17 Aug 2023 20:42 #278298 by Doug Crews
That is a great fit.
I'll give you and everyone an update when I get the boards in.

Thank you for all that you do, For everyone.

-Doug
The following user(s) said Thank You: tommylight

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27 Aug 2023 01:05 #279046 by Doug Crews
Ok, here’s where I’m at.   7i74 and 7i70 all in and seem to be doing fine.   I am getting a ssi data-incomplete error and some other errors that seems to be clock related as well.  I've been studying the  SSI absolute encoders and analog servos - LinuxCNC  thread and I've attached several photos that were asked for in that thread as well as the readhmid output and of coarse the hal file.    I really chopped off  the hal file to keep it minimal, for the moment.  My plan is to use the Show Hal Configuration GUI  to verify that I have basic functionality.  I can see the SSI encoder pins in the HAL CONFIG GUI but the raw counts don’t change with shaft movements, and I have the data-incomplete read error.The loaner encoder from my distributor isn’t the exact model that I attached earlier. This version has an 8 pin barrel connector, it must have come out of a test setup.  I’m dealing with unmarked flying leads that I’ve had to beep out…hopefully I haven’t screwed anything up working the mirror image side.  I’ve also attached the RJ45 wire scheme that I used.   There’s plenty of room for errors between my chopped hal file and getting the right wire to the right pin.  The phase-lock loop error seems ominous, hopefully I just need to tweak the DPll parameters.-Doug
 

File Attachment:

File Name: my_LinuxCN...8-26.hal
File Size:1 KB
 

File Attachment:

File Name: readhmid_2...8-26.txt
File Size:5 KB
 

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27 Aug 2023 01:21 - 27 Aug 2023 01:28 #279048 by PCW
Comment out this line:

setp hm2_7i92.0.dpll.base-freq-khz 500

The DPLL base frequency is set automatically
(to the servo thread frequency)

Also the 49 ms latency is _really_ bad so suggests a real time issue with the host
(maybe you don't have
force_turbo=1  in config.txt )

Disabling the base thread in the latency-histogram may give you better results:

latency-histogram --nobase --sbinsize 1000

 
Last edit: 27 Aug 2023 01:28 by PCW.

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27 Aug 2023 01:50 #279051 by Doug Crews
Yep, that fixed the data incomplete error and the phase lock error.  Still no change to rawcounts with shaft movements.   Probably time to start swapping data and clock wires.... Is there a way to use Hal Scope to view the data and clock stream?    I have an o-scope too.  I'm mostly fumble around with it though.  

 

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27 Aug 2023 01:59 - 27 Aug 2023 02:01 #279054 by tommylight

 Probably time to start swapping data and clock wires...
I wrote exactly that and did not post it, i can not exactly recall what but i am sure i had to invert those a time or two till it worked.

Edit:
Shame on me, forgot to add:
PCW and Andy helped me a lot back then, thank you both.
Last edit: 27 Aug 2023 02:01 by tommylight. Reason: more info

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