Shumatech DPU550

Created by: Lester Caine, Last modification: 15 Aug 2009 (08:06 UTC)
DPU550 Readout Daughterboard
Shumatech DPU550 Prices

The DRO-350 is a three-axis digital read-out (DRO) for import Chinese scales and most quadrature encoders that is designed to be as capable as commercial DROs but be a low cost alternative for the metal-working hobbyist. The DRO-350 is a do-it-yourself (DIY) project, not a complete, commercially manufactured product. All of the components necessary to build it are commonly available at Digikey, Mouser, or other electronics distributors. The printed circuit board (PCB) is specifically designed to use only DIP devices to make it easier for a hobbyist to assemble. The custom components needed to build the DRO-350, the bare PCB and the silk-screened overlay, are available to order on this site. The construction process is shown in step-by-step detail on the construction page and it is easy enough for somebody with basic electronics experience to build. If you don't feel comfortable building one yourself, you can send an e-mail to the ShumaTech Yahoo! group to see if someone is willing to build one for you.

The DPU-550 is an advanced upgrade daughterboard for the Shumatech DRO350 that plugs into the PIC microntroller socket.  It replaces the 8-bit PIC microcontroller with a far more powerful 32-bit ARM7 processor (see comparison table) with more program space for advanced features.  The PIC processor on the DRO-350 has served its task well, but it is getting antiquated compared to today's technology and more importantly, the program space is entirely used up by the DRO-350 software so there is no way to add more freatues without removing existing ones.

The DPU-550 not only includes an advanced processor, but it also adds a number of other commonly asked-for hardware features including:

  • 5 digital scale interfaces (3 from DRO-350 and 2 on-board)
  • USB device interface
  • True RS-232 communications
  • 5V 2A power supply
  • 2 edge finder ports
  • 2 flex ports (tachometer, edge finder, and/or piezo buzzer)
  • Debugging (JTAG) interface

 Processor Attribute DRO-350 PIC
DPU-550 ARM7

Register Width 8-Bit 32-bit

Speed 20MHz 50MHz

Program Memory 8K 256K

Working Memory 368 64K

Nonvolatile Memory 256 8K

Processor Registers 1 16

USB Device Interface No Yes

Free & Unlimited C Compiler No Yes

What's even more exicting is that the DPU-550 software is completely open and available via the OpenDRO project.  This will allow anyone with an interest to contribute features or fixes.  Even if you don't feel comfortable contributing, you can look at the software for more insight on how it works.  The OpenDRO software is constantly evolving with new features but a quick snapshot of what is availble includes:

  • Multi-protocol scale support (24 bit, BCD7, BIN6, and quadrature)
  • Fast scale reading with a display update rate of up to 50 times a second per axis
  • Metric/imperial units
  • Absolute and incremental zeros
  • Enter zero values for both coordinate systems entered via keypad
  • Enter incremental presets via keypay
  • Tool offsets
  • Bolthole circles
  • Sub-datum workspaces
  • Hole grids
  • Scale summing
  • Compound vectoring
  • Software upgradeable over USB & RS-232
  • PC command/control interface over USB & RS-232
  • Centerline
  • Diameter mode
  • Linear error correction
  • Multi-machine support (simultaneous mill and lathe operation)
  • Reverse polish calculator with 4 level stack
  • Zero warning with axis blink and piezo buzzer
  • Audible key press
  • Configurable scale precision up 4 decimal places in inch mode (3 for mm mode)
  • Feed rate display
  • Electronic edge finder zeroing
  • Tachometer in RPM or surface feet per minute (SFM)
  • Moving average scale filtering
  • Display brightness configurable in 20% increments
  • and More!

In addition to all of these feature, just about every facet of the DRO is configurable.  Don't like the X axis on top?  Move it down.  Want to cut on an axis and see the tachometer, feed rate, and position all at once?  No problem.  Since the software is open, if it can be thought of, it can probably be done.

The installation of the DPU-550 is designed to be as easy as possible.  It's installation is far easier than building a DRO-350.  The main part of the installation is to remove the existing PIC and solder in a pin header in its place.  Also, depending on which DPU-550 product you purchased, you might have to do some assembly of connectors or other portions of the PCB.  All of this is shown in more detail on the contruction page.

Shumatech DPU550 Prices