OpenDRO User's Guide

5.5 Setup Menu

The setup menu allows you to change the configurable parameters for each DRO object.  When you select an object type from the menu, OpenDRO switches the display to show the object instance in the top line, the parameter name for that object on the middle line, and the parameter's current setting on the bottom line.   For objects with multiple instances, like scales and axes, press the X PRESET key to cycle forward the available instance numbers and press the X ZERO key to cycle back.  Press the Y PRESET key to move to the next parameter and press the Y ZERO key to move to the previous parameter.  To change a parameter, press the Z PRESET or Z ZERO key which will, depending on the parameter, either rotate through the allowable settings or will prompt you to enter a numeric value.  After changing a parameter, you can cycle through additional parameters to change for that object instance.  You can also cycle through additional object instances. 

To permanently store your parameter changes in the DRO's non-volatile memory, press the ENTER key.  To continue without permanently storing your changes, press the CLEAR key.  If you want to return to the setting stored in non-volatile memory, then reset the DRO.

Note that the setup menu is displayed on screen as "SEtUP".  The on-screen display for each object and parameter is shown underneath their names.

Object Parameters

The following setup parameters apply to the current machine.  You can change the current machine in the system menu.

Parameter Description
Set the machine type - lathe or mill
Set the machine's tachometer - tach 1 or tach 2.

DPU-550:  The tach 2 header is dual purpose and is also used to output the scale clock for 21 bit protocol scales.  If select tach 2 as a tachometer on any machine, then the scale clock output is disabled and you you cannot use 21 bit protocol scales with the DPU-550 unless an external circuit is used to provide the clock.
Tach Divisor
Divide the tachometer signal measurement by this divisor before display.  This feature is useful if the tachometer sensor sends more than one pulse per revolution such as when detecting the movement of a gear.  Set this to the number of pulses sent per revolution.  In most cases, this can be left at the default of one.

Set the machine's edge finder - none, edge 1, or edge 2

DPU-550: You can also select tach 1 or tach 2 to mimic the DRO-350 auxiliary port where the edge and tachometer functions are shared on the same port.


Set what is shown by default on the axis displays:

  • Reading - The normal scale reading in either inches or mm.
  • Counts - The raw counts from the scale before conversion.  This is useful for troubleshooting the scales.
  • Jitter - For Chinese scales, this displays the standard deviation of the samples in the filter window.  You can use this to display a quantitative measurement of the scale jitter for troubleshooting noise problems.
Set the near-zero warning threshold.  When an axis approaches a zero within a positive or negative distance from this value, then the display will flash and the beeper, if configured, will sound.  Once a near-zero warning is triggered, then you must travel 10% farther away than this value to rearm the near-zero warning.  This prevents repeated triggering when working around the near-zero threshold.

Turn the beeper on or off.  You must turn the beeper on before any other function that uses the beeper will work.

DPU-550: Sets the tachometer port the beeper is connected to since it must be shared.

Auto Off
The number of minutes to wait before automatically turning the DRO off when it is idle.  Setting this to zero disables the auto off feature and keeps the DRO on at all times.
Auto On
The amount of axis movement for the DRO to automatically power on.  When an axis is moved by this amount, the DRO will turn on or will reset the auto off timer if already on.
Edge Beep
Turn on to enable a beep when the electronic edge finder makes contact during a zero operation.  Note that the beeper must be turned on in the machine setup before this feature will function.

For each display line on the DRO, set the axis that is displayed on it or turn off the line entirely.

LINE1 The top X display line on the DRO.
LINE2 The middle Y    display line on the DRO.
LINE3 The bottom Z display line on the DRO.
LINE4 The top W display line on the LC   D-200.
LINE5 The bottom C display line on the LCD-200.

The axis numbers are identified as follows:

  Mill Lathe

For each axis on the DRO, you can set the following parameters:

Parameter Description
Set the scale that is the primary input for this axis.
Sum a second scale into this axis.
Reverse the polarity of the axis.  When enabled, this makes all positive values negative and all negative values positive and effectively moves the directional conventions of the origin.  The default with all reverse settings turned off is positive X to the right, positive Y to the rear, and positive Z upwards.  The DRO will not function properly if you do not set the scale reverse setting properly when installing the scales (see below in scale setup).

Set the precision value to high, medium, low, or fractional.  The high, medium, and low settings control the number of displayed digits after the decimal point and depend on the current measurement units.  For a half digit, the DRO lights the right-most decimal point to represent the half value.  Also, if a configured precision cannot fit on the display, then the DRO automatically changes the precision to the next lower value until it does fit.

  Imperial Metric
High 4 3
Medium 3 1/2 2 1/2
Low 3 2

When the precision is set to fractional, the DRO will display the reading in 64ths fractions.  On the main DRO display, this is represented as "A.B.C" where A is the integral number, B is the numerator, and C is the denominator.  On the LCD-200 display, the reading is shown as "A B/C".

Linear error correction.  Enter the LEC factor in parts per million (PPM) and the reading for the axis is automatically adjusted by that amount.  1 PPM = 0.0000001.

Scale numbers 1 through 5 correspond to the scale numbers printed on the DRO printed circuit board.  For each scale input on the DRO, you can set the following parameters:

Parameter Description

Set the protocol type for the scale input to one of:

  • Auto - Automatically detect the Chinese scale type and set the CPI accordingly
  • 24BIT - The original Chinese scales that are a knock-off of the Sylvac scales.
  • 21BIT - Scales from iGaging that use the same Sylvac technology.
  • BCD7 - A less common format sometimes seen in calipers.
  • BIN6 - Format typically seen on newer Harbor Freight calipers.
  • Quadrature - Glass scales, linear and rotary encoders, or any other measuring device that sends two signals that are 90 degrees out of phase from each other.

Set the counts per inch for the scale input:

  • 24BIT - Use 20480 CPI
  • 21BIT - Use 2560 CPI
  • BCD7 - Use 2540 CPI
  • BIN6 - Use 2540 CPI
  • Quadrature - depends on the scale so check with your manufacturer
If the scale type is Auto, then this setting is automatically changed for the detected scale type except for quadrature scales.
This inverts the scale counts which reverses the direction of travel for the scale.  You should configure this only once when you initially install your scales to insure that the direction of positive travel is correct with respect to the axis when the axis reverse settings are all turned off (see above in the axis setup).  If you later want to change the direction of travel for an axis, change the axis reverse setting and leave this setting as is.  This assures that the DRO knows the absolute directions of front, rear, left, and right for features like edge compensation.
Configure an adaptive moving average filter for a non-quadrature scale.  Chinese scales are very sensitive and can suffer from display jitter due to electrical noise.  Display jitter is where the least significant digit can rapidly change its value on the display.  To work around this problem, you can configure an adaptive moving average filter that will average several readings together the number of which is dynamically determined based on the amount of movement.  The filter will not apply to quadrature scales even if configured.
Parameter Description
Set the intensity of the LED display in steps of 20%.
Parameter Description
Key Beep
This parameter turns key beep on or off.  When key beep is on, you will hear a brief "chirp" sound after every key press.  Note that the beeper must be turned on in the machine setup before this feature will function.