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Home Forum Configuring LinuxCNC PnCConf Wizard 7i77 testers wanted

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TOPIC: 7i77 testers wanted

Re:7i77 testers wanted 22 Giu 2012 20:28 #21213

  • cmorley
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ahh yes software encoder has a x4 mode that can be set false for the same effect.
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Re:7i77 testers wanted 22 Giu 2012 21:10 #21214

  • PCW
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"Is there another reason this is not suitable?"

Yes, the Hostmot2 encoder counter firmware in "counter mode"
is an up down counter, which is not the same as a 1X quadrature counter.

A 1X quadrature counter counts

up on the rising edge of A
down on the falling edge of A
when B is high


The hostmot 2 counter always counts on the rising edge of A (ignoring the falling edge),
counting up when B is high and down when B is low

The reason this does not make a good 1X quadrature encoder counter
is easy to imagine if you think of teasing the dial on a MPG at the A edge
Say B is high, now every time A falls and rises the counter counts up even though
the dial has not moved from the edge of A

The counter mode was made for counting single sensors and frequency counting

There is a workaround for this on the 7I76,7I77,and 7I69 with the latest firmware,
these all have 2 channel (A,B only no index) 1x encoder counters (1x is default) built-in
one of their sserial "modes" (inputs 0 through 3 on the 7I77 are used for 2 encoders for example)
the 7I76 and 7I77 encoder modes also set the input threshold to 2.5V on those pins
Last Edit: 22 Giu 2012 21:43 by PCW. Reason: clarify
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Re:7i77 testers wanted 22 Giu 2012 23:12 #21215

  • cmorley
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we need to change the docs then. it implies that counter mode with an encoder is fine.
It would be nice to add 1x mode to hostmot2 encoders. MPG with a quadrature doesn't work quite right either.

Thanks for explaining
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Re:7i77 testers wanted 23 Giu 2012 08:40 #21227

  • PCW
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Well it will work but will lose or gain counts if A toggles back and forth
Probably not a big deal to add 1X mode to the counter if I can figure out
where to add the mode bit
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Re:7i77 testers wanted 25 Nov 2012 12:36 #26922

  • nkp
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Hello!
Could you please tell me how in 5i25+7i77 to switch modes :
MODE 0 I/O only mode (32 bits of input data, 16 bit of output data)
MODE 1 I/O plus analog input mode (32 bits of input data, 16 bits of output data, 4
      analog input channels on inputs 0..3)
MODE 2 I/O plus analog input and field voltage mode (32 bits of input data, 16 bits of
      output data, 4 analog input channels (on inputs 0..3) and field voltage analog
     in)
MODE 3 I/O plus analog input and field voltage mode (32 bits of input data, 16 bits of
      output data, 4 analog input channels (on inputs 0..3), field voltage analog in
     and 2 MPG encoders on inputs 16..19). Default encoder count mode is 1X
    to match normal 100 PPR MPGs. Encoder input threshold is fixed at 2.5V for
   compatibility with 5V encoder outputs.
to get ANALOG INPUTS:
All field input pins are capable of reading the input voltage. These are not highly
accurate or high resolution but can be useful for things like potentiometer inputs. Input
resolution is 8 bits and input full scale value is 36.3V. Accuracy is +-5%
Software process data modes 1 and 2 allow reading the analog voltage on inputs
0 through 3, in addition to the 32 digital bit inputs
thanks
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Re:7i77 testers wanted 25 Nov 2012 14:50 #26925

  • PCW
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You change the "sserial_port_0=SOMETHING" parameter in the
firmware config line at the top of the .ini file to sserial_port_0=M00xxx"

where M is the mode for the 7I77 field I/O (0,1,2,3)

Note that the MPG option (mode 3) was added
recently and may not be present on your 7I77
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