My new DRO

[jpanhalt]

My Aikron A30P just arrived -- 3-axis + RS232 (baud 115,200) output.  Can't wait to fire it up.  Will replace my 1990's Mitutoyo DRO on a mill.  What sold me was high baud rate, 3-axis, and built-in calculations.  Of course 3-axis and calculations are common, but the high baud rate is not.  Price:$164 USD + shipping, which was express DHL @ $50.83.  The other factor was the co-founder of Aikron, Aiken Yu.  Very communicative and knowledgeable.   It comes with a very sturdy mounting arm.  Sorry for the fuzzy photos, low light and out of position.

I have old Ellis and Yuasa dividing attachments with chucks. Is there any reason the calculation ability doesn't replace the horizontal indexing device, i.e., for milling holes on a diameter, etc?

[totalnoob]

The only reason that it can't is if that feature is not built into it. Since I am unfamiliar with this DRO, I don't know if it has that capability or not. I have seen what you proposed done on some metalworking Youtube channels. Their DRO's have a bolt circle function that can do this.

I'm interested in hearing your thoughts and seeing your posts once its installed and you're using it. I need to add a DRO to my mill.

[jpanhalt]

I have not used it yet, but it definitely has the bolt circle calculator function and many others.  I think that might be pretty standard today but wasn't in the early 90's.  It was the high speed RS232 that attracted me (all the others I saw were just 9600 baud) as a "manual CNC" or maybe more without having to add encoders to each dial.

EDIT: The functions it has are: Grid hole, Bolt holt (circle), Simple radius, Smooth radius, Pocket, Radius/Diameter conversion, Vectoring, Taper, Tool offset, EDM, Distance to go, and Signal test.  There is also linear compensation and other usual stuff.

EDIT2:  It is plug compatible with the YHSINO glass scale I got first.  Glass scales are heavy, so I got that from a US importer in California.  I could not find an A30P version in the US at a competitive price to the one shipped from China.

[totalnoob]

I figured it probably did have those kinds of functions, but you never can tell. The radius and tapering features won't help me, I can't synchronize my hands to spin the handwheels at the different speeds needed to take advantage of those functions.

[thm_w]

https://www.aikrondro.com/product/aikron-a30p-lcd-digital-readout/

Its membrane buttons right? All of the lower end displays I can find seem to all have membrane. Then its like $500+ for regular switches. Probably OK if its metal dome.

There are also touch screen units but.... I personally can't see that working as I always use gloves: https://www.aliexpress.us/item/1005004877377437.html

[jpanhalt]

I have only turned it on once to see if it works,  It appears to be membrane switches, but I am not sure.  The version I got is 3-axis with RS232 output but no RPM or touch sensor.

I don't wear gloves, but I have extremely dry skin and ordinary touch screens (like at WalMart checkout or kiosks at airports) do not work for me.  I need a stylus or keypad.  I just got a nice 9-pin male-female breakout board so I can sort out the signal from the Mitutoyo scales and try to make an interface.  Hope springs eternal, but Sino glass scales are relatively cheap, if needed.

Long term, I may add a used "servo" drive to the Y-axis lead screw* with servo motors to make a redneck CNC for simple, 2D things.

* I have a Servo brand drive on the X-axis of the mill (42" table), but there is a distinct delay before it engages.  I like the compact design with gears rather than belts.  With feedback from the scales, one can drive to a position rather than number of turns as with most inexpensive CNC's.

[jpanhalt]

UPDATE

I decoded the linear scales on my old Mitutoyo DRO and expected to see quadrature or something like that.  That isn't what I saw with the break-out board. Then, I looked at the part number on the scales.  They are both older Digimatic 572 series scales.  Suddenly, it makes sense.  They respond to the MRO display with thirteen, 4-bit bytes just as the spindle does.  See related post here:
https://www.eevblog.com/forum/microcontrollers/stymied-why-are-my-data-sometimes-doubled/

If one searches on that series or on the display, there are lots of questions, but few answers.  I am starting a new thread here with the Mitutoyo number in the title so others can find it.

Here's the link to that new thread:
https://www.eevblog.com/forum/mechanical-engineering/mitutoyo-982-537-1-dro-display-with-series-572-linear-scales/new/#new

[thm_w]

Here is the inside of a HS800-2, 2-axis DRO. <$200 with two scales. Could be similar hardware to the Aikron, or could be completely different inside.
Power consumption 2W. Tactile dome switches. Decent refresh rate.




Simplistic inside:
- STM32F030 for the main micro.
- LT7688 to drive the large LCD, looks like a cool chip: http://www.levetop.tw/data/LT7688_BFDS_V10_ENG.pdf Can't find anywhere selling it though.
- EEPROM for settings

Missing parts:
- Z-axis connector
- JK1 relay for EDM
- J12 or J8 is probably the RS232/RS485 connection, though there is no RS485 driver on this board I see

Setting screen its quite generic, some of options to choose:


Display: Linear, Angle
Type: Grating, Encoder
Resolution: 0.01 and up
Direction: Positive, negative
ComMod: Linear, non-linear

There is a default password of 2008, I assume there is a setup password or key sequence for initial programming, to set number of axis, etc. But not sure what that is.

[jpanhalt]

Your post was the incentive I needed to open up the Mitutoyo 982-537-1 controller/display.  The bottom of the board is just TH soldered components.  Here's the top:


It was surprise to find batteries.  One of the Panasonic alkalines had leaked.  The other was in perfect condition.  Removed the battery holder, cleaned it up in an ultrasonic with a little chemistry.  Looks good, but most of the plating is gone from the positive contact for the corroded battery.  New batteries seem to work fine.  For others who may find this, opening the case is a little tricky.  There are 2 obvious screws from the bottom that hold the display face.  But nothing moved.  It turns out that the 4 hex standoffs for the DB-9's must be removed, and then it comes apart very nicely. 

The chips are an AMD dated 1986 with PRGM on it.  The microcontroller is labeled Intel 1980 and its part number is apparently a P80C138H for which I could find nothing.  Other chips are a 74HC3738(B?)B1, 74HC14 (Schmitt inverter), 74HC139N (2 to 4 line decoder), MIC2951-02BN (voltage regulator), LM339, and 2x 2n3904 transistors.  The crystal is 12 MHz.