Re: DRO suggestions (computer input like via USB)

On Tue, 12 Jun 2007 12:41:48 -0400, Lloyd E. Sponenburgh <lloydsp@xxxxxxxxxxxxxx> wrote:

"Ignoramus27221" <ignoramus27221@xxxxxxxxxxxxxxxxxxxx> wrote in message
news:M56dnQ8fG47dWvPbnZ2dnUVZ_i2dnZ2d@xxxxxxxxxxxxxxx
Please forgive me if my question is wrong or stupid. Is that true that
"scales that output TTL quadrature" could be directly connected to the
parallel port?

Or do I need some sort of a multiplexer to take inputs from several
(say 3) scales and outputs one stream of signals to the parallel port?

I am browsing that website and would say that it would be quite close
to what I want if I can get the scales to send their positioning data
into my computer.

Not a dumb question, Iggy. Quadrature outputs occupy two bits. So, you
have enough inputs on the parallel port to handle up to four encoders.

If the i/o chip on the parallel is the right sort (old 8255-ish behavior,
perpetuated in more modern on-board integrated I/Os), you can set the chip
to interrupt on any input change. That'll avoid your having to poll the
chip constantly; you can just update the position information in an
interrupt handler when a bit twiddles.

OK, thanks Lloyd. Check this out:

http://www.vitalsystem.com/web/motion/motionLite.php

It is supported by EMC2.

Part 7544 and 7525 should cover the needs for reading information from
encoders and will also permit some forms of machine control. I will
give them a call when I get some time.

i

======================================================================
The MOTENC-Lite PCI board is designed for PC based real-time systems
controlling machines that require precision motion control. These
include, CNC machines, Routers, Pick and Place machines, Robots and so
on. The board has all the necessary components to implement a
precision digital feed back control system. Analog outputs from the
board drive the Motor Amplifiers using industry standard ±10V
interface. The position feedback is generated by the quadrature
encoder counters using 32-bit resolution. Utilizing the full 32-bit
PCI bus, the board allows reading the 32-bit counter in just one read
cycle. The Analog output settling time is just under 5 micro-sec and
the CPU read-write cycle times are within 500 nano-sec. This allows
the PID feedback loop update rate of 20KHz or more. The board has
digital I/O to connect home, limit, and other switches and relays to
implement a complete control system.

The MOTENC-Lite board is supported on EMC/EMC2 (Enhanced Machine
Control) software. EMC is a software system for computer control of
machine tools such as milling machines. More info available at
www.LinuxCNC.org.

Product Highlights:

*

Eight Channels Analog Outputs, Range ±10V, 13-Bit Resolution
*

Eight Channels Analog Inputs, Range ±5Volts, 14-bit Resolution
*

Four Differential Quadrature Encoder Inputs. 32-Bit Resolution
*

2Mhz Max encoder frequency. Encoder resolution is multiplied by
4 in hardware
*

48 Digital I/O (32 Inputs & 16 Outputs) in two 50-pin
headers. Opto-22 compatible
*

10 additional Digital I/O (6 Input,4 Output) on two SIP headers.
*

Programmable Timer Interrupts
*

Watch Dog Timer
*

Optional Hardware ESTOPs Input Signals (Jumpers on board to
override if not needed)
*

Hardware Board ID for multiple board applications
.

Relevant Pages

  • Re: Advice / Info on Acu-Rite ENC 250 Feedback Scales
    ... tube spinning machines we are upgrading to CNC control. ... retrofitting spinning machines are using Sinumerik controls. ...
    (alt.machines.cnc)
  • Re: Controling Holiday Lights
    ... You can build controllers using a solid-state relay ... controlled from a parallel port and switching a 120v circuit. ... The 3-15vdc control input means most PC parallel ports should be able to ... about as many lights as you would ever put on one circuit. ...
    (comp.home.automation)
  • Need help to use parallel port to control 8 digital potentiometers
    ... control 8 digital potentiometers through the parallel port. ... Each pot needs to have a serial clock in, control signal in, and serial ... to control the other two signals needed by each digital pot. ...
    (comp.lang.labview)
  • Re: ... and while Im asking, what about Romi?
    ... Now you know why it comes with a shorty bar loader though. ... With a GE Fanuc control it should be reliable. ... > My experience with Brazilian machines is limited to the Nardini's. ... > lathes that we finished off when Nardini was reorganizing. ...
    (alt.machines.cnc)
  • Re: Advice / Info on Acu-Rite ENC 250 Feedback Scales
    ... tube spinning machines we are upgrading to CNC control. ... retrofitting spinning machines are using Sinumerik controls. ...
    (alt.machines.cnc)