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Using a Servo for a Mill spindle 7i76e

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08 Jul 2020 17:17 #173997 by arvidb
Replied by arvidb on topic Using a Servo for a Mill spindle 7i76e
"turn the spindle by hand slowly" - very slowly even, or use an oscilloscope. The transitions are way too fast for a normal voltmeter otherwise. You also won't see anything at zero spindle speed, of course.

What you are looking for is a toggling of voltage levels: if you have a differential encoder I guess they should toggle between similar positive and negative voltages. The levels will toggle thousands of times per revolution. Single ended toggles between ~0 V and some positive value.

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08 Jul 2020 17:23 #173998 by Clive S
Replied by Clive S on topic Using a Servo for a Mill spindle 7i76e

You should measure ~+3 or ~-3 across the A,B differential pairs
(and never close to 0) if you wiggle the shaft around to see all
quadrature states


Thanks Peter
So I should see around 3V across a pair but I am only seeing about 17mV with the servo doing 100 rpm but 3V when stopped

Is that correct?

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08 Jul 2020 17:27 #173999 by PCW
Replied by PCW on topic Using a Servo for a Mill spindle 7i76e
That sounds correct (because the signals should alternate between about +3 and -3 so the voltmeter will average this to ~0 when moving)

What firmware in on the 7I76E? (the encoder mapping can change depending on
the installed firmware)

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08 Jul 2020 18:07 - 08 Jul 2020 18:17 #174004 by Clive S
Replied by Clive S on topic Using a Servo for a Mill spindle 7i76e

That sounds correct (because the signals should alternate between about +3 and -3 so the voltmeter will average this to ~0 when moving)

What firmware in on the 7I76E? (the encoder mapping can change depending on
the installed firmware)


Ah light bulb moment I was playing with this servo before connected to a 7i85s so I will have flashed it for that card.

Now I am just using the 7i76e using the encoder on TB-3

General configuration information:

  BoardName : MESA7I76
  FPGA Size: 16 KGates
  FPGA Pins: 256
  Number of IO Ports: 3
  Width of one I/O port: 17
  Clock Low frequency: 100.0000 MHz
  Clock High frequency: 200.0000 MHz
  IDROM Type: 3
  Instance Stride 0: 4
  Instance Stride 1: 64
  Register Stride 0: 256
  Register Stride 1: 256

Modules in configuration:

  Module: DPLL
  There are 1 of DPLL in configuration
  Version: 0
  Registers: 7
  BaseAddress: 7000
  ClockFrequency: 100.000 MHz
  Register Stride: 256 bytes
  Instance Stride: 4 bytes

  Module: WatchDog
  There are 1 of WatchDog in configuration
  Version: 0
  Registers: 3
  BaseAddress: 0C00
  ClockFrequency: 100.000 MHz
  Register Stride: 256 bytes
  Instance Stride: 4 bytes

  Module: IOPort
  There are 3 of IOPort in configuration
  Version: 0
  Registers: 5
  BaseAddress: 1000
  ClockFrequency: 100.000 MHz
  Register Stride: 256 bytes
  Instance Stride: 4 bytes

  Module: StepGen
  There are 13 of StepGen in configuration
  Version: 2
  Registers: 10
  BaseAddress: 2000
  ClockFrequency: 100.000 MHz
  Register Stride: 256 bytes
  Instance Stride: 4 bytes

  Module: MuxedQCount
  There are 10 of MuxedQCount in configuration
  Version: 3
  Registers: 5
  BaseAddress: 3600
  ClockFrequency: 100.000 MHz
  Register Stride: 256 bytes
  Instance Stride: 4 bytes

  Module: MuxedQCountSel
  There are 1 of MuxedQCountSel in configuration
  Version: 0
  Registers: 0
  BaseAddress: 0000
  ClockFrequency: 100.000 MHz
  Register Stride: 256 bytes
  Instance Stride: 4 bytes

  Module: SSerial
  There are 1 of SSerial in configuration
  Version: 0
  Registers: 6
  BaseAddress: 5B00
  ClockFrequency: 100.000 MHz
  Register Stride: 256 bytes
  Instance Stride: 64 bytes

  Module: LED
  There are 1 of LED in configuration
  Version: 0
  Registers: 1
  BaseAddress: 0200
  ClockFrequency: 100.000 MHz
  Register Stride: 256 bytes
  Instance Stride: 4 bytes

Configuration pin-out:

IO Connections for on-card
Pin#  I/O   Pri. func    Sec. func       Chan      Pin func        Pin Dir

 1      0   IOPort       StepGen          0        Dir/Table2      (Out)
14      1   IOPort       StepGen          0        Step/Table1     (Out)
 2      2   IOPort       StepGen          1        Dir/Table2      (Out)
15      3   IOPort       StepGen          1        Step/Table1     (Out)
 3      4   IOPort       StepGen          2        Dir/Table2      (Out)
16      5   IOPort       StepGen          2        Step/Table1     (Out)
 4      6   IOPort       StepGen          3        Dir/Table2      (Out)
17      7   IOPort       StepGen          3        Step/Table1     (Out)
 5      8   IOPort       StepGen          4        Dir/Table2      (Out)
 6      9   IOPort       StepGen          4        Step/Table1     (Out)
 7     10   IOPort       SSerial          0        TXData1         (Out)
 8     11   IOPort       SSerial          0        RXData1         (In)
 9     12   IOPort       SSerial          0        TXData2         (Out)
10     13   IOPort       SSerial          0        RXData2         (In)
11     14   IOPort       MuxedQCount      4        MuxQ-IDX        (In)
12     15   IOPort       MuxedQCount      4        MuxQ-B          (In)
13     16   IOPort       MuxedQCount      4        MuxQ-A          (In)

IO Connections for P1
Pin#  I/O   Pri. func    Sec. func       Chan      Pin func        Pin Dir

 1     17   IOPort       SSerial          0        RXData3         (In)
14     18   IOPort       SSerial          0        TXData3         (Out)
 2     19   IOPort       StepGen          8        Step/Table1     (Out)
15     20   IOPort       StepGen          8        Dir/Table2      (Out)
 3     21   IOPort       StepGen          7        Step/Table1     (Out)
16     22   IOPort       StepGen          7        Dir/Table2      (Out)
 4     23   IOPort       StepGen          6        Step/Table1     (Out)
17     24   IOPort       StepGen          6        Dir/Table2      (Out)
 5     25   IOPort       StepGen          5        Step/Table1     (Out)
 6     26   IOPort       StepGen          5        Dir/Table2      (Out)
 7     27   IOPort       MuxedQCountSel   0        MuxSel0         (Out)
 8     28   IOPort       MuxedQCount      0        MuxQ-A          (In)
 9     29   IOPort       MuxedQCount      0        MuxQ-B          (In)
10     30   IOPort       MuxedQCount      0        MuxQ-IDX        (In)
11     31   IOPort       MuxedQCount      1        MuxQ-A          (In)
12     32   IOPort       MuxedQCount      1        MuxQ-B          (In)
13     33   IOPort       MuxedQCount      1        MuxQ-IDX        (In)

IO Connections for P2
Pin#  I/O   Pri. func    Sec. func       Chan      Pin func        Pin Dir

 1     34   IOPort       SSerial          0        RXData4         (In)
14     35   IOPort       SSerial          0        TXData4         (Out)
 2     36   IOPort       StepGen         12        Step/Table1     (Out)
15     37   IOPort       StepGen         12        Dir/Table2      (Out)
 3     38   IOPort       StepGen         11        Step/Table1     (Out)
16     39   IOPort       StepGen         11        Dir/Table2      (Out)
 4     40   IOPort       StepGen         10        Step/Table1     (Out)
17     41   IOPort       StepGen         10        Dir/Table2      (Out)
 5     42   IOPort       StepGen          9        Step/Table1     (Out)
 6     43   IOPort       StepGen          9        Dir/Table2      (Out)
 7     44   IOPort       MuxedQCountSel   8        MuxSel0         (Out)
 8     45   IOPort       MuxedQCount      2        MuxQ-A          (In)
 9     46   IOPort       MuxedQCount      2        MuxQ-B          (In)
10     47   IOPort       MuxedQCount      2        MuxQ-IDX        (In)
11     48   IOPort       MuxedQCount      3        MuxQ-A          (In)
12     49   IOPort       MuxedQCount      3        MuxQ-B          (In)
13     50   IOPort       MuxedQCount      3        MuxQ-IDX        (In)
Last edit: 08 Jul 2020 18:17 by Clive S.

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08 Jul 2020 18:48 - 08 Jul 2020 18:49 #174007 by PCW
Replied by PCW on topic Using a Servo for a Mill spindle 7i76e
Right so if you are using that firmware, the 7I76Es local encoder is encoder 4...
Last edit: 08 Jul 2020 18:49 by PCW.
The following user(s) said Thank You: Clive S

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08 Jul 2020 19:04 #174008 by Clive S
Replied by Clive S on topic Using a Servo for a Mill spindle 7i76e

Right so if you are using that firmware, the 7I76Es local encoder is encoder 4...


Ok I have not got the 7i85 card plugged in. Also got no field power connected.

Will I have to changed the load line in the hal file to encoders =5 and change all the encoder bits in the hal file from encode.00 etc to encoder.04 etc

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08 Jul 2020 19:07 #174010 by PCW
Replied by PCW on topic Using a Servo for a Mill spindle 7i76e
Either that or re-install the stock firmware

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08 Jul 2020 19:18 #174011 by Clive S
Replied by Clive S on topic Using a Servo for a Mill spindle 7i76e

Either that or re-install the stock firmware


Thanks for your patience.

loadrt hm2_eth board_ip="10.10.10.10" config=" num_encoders=5 num_pwmgens=0 num_stepgens=5 sserial_port_0=00xxxx"

# ---Encoder feedback signals/setup---

setp [HMOT](CARD0).encoder.04.counter-mode 0
setp [HMOT](CARD0).encoder.04.filter 1
setp [HMOT](CARD0).encoder.04.index-invert 0
setp [HMOT](CARD0).encoder.04.index-mask 0
setp [HMOT](CARD0).encoder.04.index-mask-invert 0
setp [HMOT](CARD0).encoder.04.scale [SPINDLE_0]ENCODER_SCALE

net spindle-revs <= [HMOT](CARD0).encoder.04.position
net spindle-vel-fb-rps <= [HMOT](CARD0).encoder.04.velocity
net spindle-index-enable <=> [HMOT](CARD0).encoder.04.index-enable

Still no joy. servo is running at 100rpm
Attachments:

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08 Jul 2020 19:20 #174013 by PCW
Replied by PCW on topic Using a Servo for a Mill spindle 7i76e
Sorry the on card encoder is the last one (encoder 8)

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08 Jul 2020 19:40 #174016 by Clive S
Replied by Clive S on topic Using a Servo for a Mill spindle 7i76e

Sorry the on card encoder is the last one (encoder 8)


No need to be sorry its a big learning curve but I am getting better.

Success. That was it . What is the name of the standard bit file as it seems wrong to have 8 encoders loaded.

Many thanks.:)

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