Build: XZero Predator... With more teeth!

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08 Oct 2019 18:52 - 08 Oct 2019 21:40 #147482 by ihavenofish
alright. control time for the little machine.

PC hardware is:
- temp PC lenovo core 2 duo
- mesa 5i25 / 7i76

On the panel i will have:
- "usb hid keyboard" with 67 keys
- display port monitor with 2048 x 1536 resolution - no touch screen
- start and stop buttons
- MPG wheel
- override encoder knob
- torque load LED bar
- override encoder LED ring
- side LED bards for alarm /status codes

Below the panel will be
- "ON" and "OFF" buttons
- coolant on / off switch
- compressor on / off switch
- emergency stop button
- door interlock switch
- cabin lights on / off switch
- dust extraction on / off switch

on the machine itself we have
- X servo (step / dir
- Y servo (step / dir
- Z servo (step / dir
- future A servo (step / dir
- ATC servo (step / dir
- x, y, z home
- ATC safety position
- x, y, z hard limits
- x/y/z servo alarms
- ATC absolute encoder encoder (SPI or I2C or PWM variants)
- spindle control (analogue +-10v
- spindle "clamp" / "unclamp" output
- spindle clamp sensor
- spindle unclamp sensor
- spindle air blast
- spindle encoder (single ended 24v)
- spindle torque feedback
- mist coolant on / off
- air blast on off
- vacuum on / off (for monitoring only, maybe later use with robot)
- vacuum pressure alarm
- tool setter input
- touch probe input

What did i miss? haha. Theres a lot of crap in this tiny machine. most of it is straightforward IO and a keyboard emulation. Some of it, i dont know yet.

ATC encoder for example. the Brother uses a BCD encoder wheel with 4 inputs. i probably could just make that if need be. The absolute encoder is nicer / chjeaper / easier. How do i get that signal into linuxcnc? Its a sanity check sensor and for homing. Not used dynamically. The servo will drive to where it needs to go accurately, and the encoder will be read and error if its not right.

Controlling the various LEDs is another conundrum. They can be run by the keyboard emulation mcu, But how do i tell them their commands? Write a driver?

Halp! :)
Last edit: 08 Oct 2019 21:40 by ihavenofish.

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08 Oct 2019 21:21 #147498 by PCW

ATC encoder for example. the Brother uses a BCD encoder wheel with 4 inputs. i probably could just make that if need be. The absolute encoder is nicer / chjeaper / easier. How do i get that signal into linuxcnc? Its a sanity check sensor and for homing. not uses dynamically. The servo will drive to where it needs to go accurate, and the encoder will be read and error if its not right.


Hostmot2 can read SSI absolute encoders, and some of the cheap magnetic absolute encoders have a SSI option

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08 Oct 2019 21:32 #147499 by ihavenofish
My linear one is ssi (actually, good to know that, cause im using it in a product and directly using ssi could be a more clever option.

Some of the the rotary mag encoders are SSI. the lower es ones. 12 bit. 4096 lines per turn. thats about 0.15mm at the tool fork. And even tighter id i put it on a belted down motor shaft. "will do" haha.

ams.com/as5045b

So where does this get hooked up? And can you use more than 1 at a time? I could use these instead of the encoders for the dials (not the mpg).

I have a second serial break out mesa board with more IO, (forget which model), so I'm not short on regular IO.

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08 Oct 2019 23:54 #147514 by tommylight
For SSI you would need a Mesa 7i74 as it has 8 ports but if i remember correctly, one of them can not be used due to..........PCW, help !
There are also 2 bit files that PCW made for me several years back, one has 4SSI and the other has 6 on a 7i74. That bit file was for a 5i25, and it can be found on a topic named Elumatec sbz 130/1 retrofit.
Maybe, in case you need only one, PCW can enlighten us if the SSerial port on a 7i76 or 7i77 can be used for SSI.

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09 Oct 2019 00:01 #147517 by ihavenofish
Ok, ill look that one up.

My linear scales are only absolute over 2mm. Then they repeat. I expect that linuxcnc could count the crossings of 0?

I currently have step and direction servos, with no encoder outputs (iHSV57). So I don't know if the scales are that useful. But at some point I may change to more high performance servos.

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09 Oct 2019 00:03 #147518 by ihavenofish
Oh, I should also note that the little demo boards they offer don't have a differential signal. just single ended 5v.

Cable runs are only 2 feet or so.

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