Re: Update on closed-loop to the computer with Gecko 320

Mariss, if you want to start using FPGAs, I would suggest you learn a
hardware description language like Verilog of VHDL (what I prefer)
and get Synplicity (www.synplicity.com). It's the best synthesis tool
for the money and beats many more expensive packages. You can then
design your FPGAs independent of FPGA architecture, sythesize for a
particular FPGA architecture, then run the place and route tool
provided by the FPGA vendor to finish the job. Altera offers a free
version of their tools on their website that handles all but the
latest and largest parts. I'm not sure if Xilinx has a free version.

Best Regards,

~petev

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Mariss Freimanis"
<mariss92705@y...> wrote:

> Jon,
>
> 1) Do not use the HCPL-2530. It's gain is only 9%.
>
> 2) Do not use a 74HC part as a buffer. It's only good for +4/-8mA.
> Use 74AC parts; they are good for +/-24mA. Same pinouts (7414 =
> 74HC14 = 74AC14).
>
> 3) Meant as written. ENC+ (+5VDC) is also the virtual analog

ground.

> This makes it a node, meaning current flows into and out of it. If
> current flows into it (from internal analog circuits), it causes

the

> node voltage to rise above the regulated +5VDC. A 470 ohm resistor
> ensures that can't happen; the encoder load normally takes care of
> that.
>
> 4) It is symmetrical. Your brushes may have set in a direction. Run
> the motor a few hours in the opposite direction and try again.
>
> 5) PID tracking is an unecessary luxury for this price drive. The
> drive is tuned for a particular system power supply that normally
> will not change over the service life of the system. That leaves
> ripple voltage which is an insignificant second-order effect.
>
> 6) Fine-pitch placement requires machine vision. This slows a

machine

> down from 15,000 parts / hr to about 3,000 / hr. and we have a
> Zevatech FS740 for that. I try to avoid fine-pitch packages for

that

> reason; time is money.
>
> Whose FPGAs are you using? Xilinx? I ask because I'm learning to

use

> their 9500 series CPDLs which I will eventually use to replace the
> SOIC glue logic in all our drives.
>
> 7) Eliminate the D term by turning the DAMP trimpot full CCW.
> Eliminating the I term requires shorting an 0805 capacitor.
>
> Mariss