RE: tach
Rick Sparber
Roy,
Well, maybe we are making progress. [Setup [Machine has more inconsistencies than I thought. Shumate was going to change the software to use the “flex” terminology that he wanted but clearly he has not done it yet. The shortcut table is, however, consistent with the present software. I don’t expect him to make any more changes to the software so will change the guide to match the current prompts.
I am seeing some strange behavior that I never saw before:
1. Z shows position
2. [status [tach Enter, Enter; select line Z.
3. I now see the text “Line” in the Z display.
4. [Setup [Mach, Enter; [tach [tach2, enter
5. I now see “tach2” in the Z display
6. I then power cycled the DRO and the text was replaced by a toggling between 0 and 184.
7. When I turned on the mill, the display read the correct RPM.
8. Clearly there is a software bug here.
I think we are trying to debug your system with more than one bug present.
See my comments below.
From: Roy Simpson
[mailto:dch...@live.com]
Sent: Sunday, November 08, 2009 4:22 PM
To: rgsp...@aol.com
Subject: RE: tach
Ok we have a change.
I selected tach 1 (per the guide that should be flex 1 in the program, if it is not, I have never seen flex on any display??), got a zero on the display that changes from zero to INF, slow flash type thing.
11/8/2009 6:51 AM
This is similar to my toggling between 0 and 184.
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I had the tach plugged into the AUX port on the 350 (not 550 as before) board for all these tests.
11/8/2009 6:51 AM
Good. That is where it must go.
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I then tried tach 2 (just to try something), got INF
11/8/2009 6:51 AM
This should not work since you don’t have a tach 2.
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I have the edge function in setup, set to none, just a note.
11/8/2009 6:51 AM
Have you been able to get the edge finder function to work?
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At least I have it flashing, never thought to abandon the 550 connection and use the 350 aux connection.
There was one time that I had it set to tach 1, nothing plugged in and I got a Zero that flashed 148,XXX, can not remember the exact number.
Still will not work with or without a tach plugged in.
11/8/2009 6:51 AM
Can you tell me the tach’s output voltage when high and when low?
Rick
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Roy
From: rgsp...@aol.com
To: dch...@live.com
Subject: RE: tach
Date: Sun, 8 Nov 2009 13:56:21 -0700
Roy,
I found a bug in the User’s Guide that may be the problem. Before you can use the tach, you must define which port it is on. Go to [Setup [Machine and press Enter. Then press the Y preset once to see [flex selection [flex 1 or [flex 2. Since you have a Lite, select flex 1 and feed your tach into the AUX port on the DRO-350 board.
Please let me know if this works. It solved my problem.
Rick
From: Roy Simpson
[mailto:dch...@live.com]
Sent: Sunday, November 08, 2009 9:59 AM
To: rgsp...@aol.com
Subject: RE: tach
I will connect the tach to the tach 2 port on the 550 board.
That connection gets power (5v) off the 350 board.
I tried to plug the tach into the tach 2 slot and the edge tach slot changing setup as required, still INF. I have not seen it switch from 0 to INF, just a solid INF.
I purchased 6 ea. Fairchild QRB1114, so that I could try different values of R1 and R2 and if needed a capacitor in the signal line. I have found much info. covering setup of just the Fairchild QRB1114. I now have at least a basic understanding of option for calibrating the Fairchild QRB1114.
The only document I have to use at all covering the tach function is the one you wrote. I could not find anything else on the subject, even info. to have anything to do with the tach function is very limited.
Thanks
Roy
From: rgsp...@aol.com
To: dch...@live.com
Subject: RE: tach
Date: Sun, 8 Nov 2009 09:15:54 -0700
Roy,
Thanks for clarifying your problem. I always like to start with the “dumb” questions before digging into the complex.
The User’s Guide was written for the DPU-550 (Full). Shumate was going to send me text to mark what is different for the Lite but he never did it. I do know that the Lite has no 5V power supply, scales 4 and 5, or edge/tach 2 nor RS232 interface.
When I wrote the tach section of the user’s manual, it did work. But now I see that my display toggles between 0 and INF. Before I can help you, I must figure out what has changed in my set up. I do have a different software load but it could also be hardware. When I pull the tach’s plug, I still see the display toggle between 0 and INF.
We do have slightly different hardware. I have an early prototype of the DPU-550 (Full) that was hand soldered by Shumate. IIRC, it also has pull down resistors on the tach input rather than pull ups. Now, given that you have the Lite version, are you connected to the mother board or to the daughtercard tach input?
As long as your voltages are correct, I see no harm in connecting the tach to the DRO. Who knows, it might work. If the software measures period and then inverts to show RPMs, you would see INF with no input. Now, that does not explain what I see.
As a side note, I have heard very little discussion that references the User’s Guide so can’t judge what needs to be improved. What has been your experience with this document?
Rick
From: Roy Simpson
[mailto:dch...@live.com]
Sent: Sunday, November 08, 2009 7:57 AM
To: rgsp...@aol.com
Subject: RE: tach
Yes the sensor is functioning, that is not my issue. I have not plugged it into the DRO, because I can not get the DRO to read anything but INF.
When I try and get the DRO to show zero on the display (when going to tach display), all I can get is INF. I understand INF stands for infinity.
I thought I'd see a zero on the display with nothing plugged into the tach port.
I'm guessing I am missing something that needs setup in setup. I can only find two areas that have to do with the tach function. One being in the [Setup [Machine menu area and the second being in the [Status [Tachometer menu area.
Thanks
Roy
From: rgsp...@aol.com
To: dch...@live.com
Subject: RE: tach
Date: Sun, 8 Nov 2009 07:11:30 -0700
Roy,
11/8/2009 6:51 AM
Please see below for my comments.
Rick
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From: Roy Simpson
[mailto:dch...@live.com]
Sent: Saturday, November 07, 2009 5:11 PM
To: rgsp...@aol.com
Subject: RE: tach
Thanks for the response.
I'm having difficulty in setting my (350/550 lite) to get anything but "INF" on the selected display line, been sellecting Z. It does not matter, if I select another line, X-Y still get INF.
11/8/2009 6:51 AM
For starters, we need to verify that the tach is working right. Assuming you have a voltmeter, connect the COM lead to the ground of the circuit. Connect the V lead to the +5V side. Do you see between +4.75V and +5.25V?
If you do, move the V lead of the meter to the “AUX Input” node. With the photo sensor blocked, what voltage do you read? Next use a mirror to direct the light into the photo sensor and again read the voltage.
If you see AUX Input go to above 3V with the light blocked and below 2V when the light can get to the photo sensor, then we know that the circuit is working.
Assuming you passed this last test, we need to look at the surface you are using to pick off the rotation. With the tach assembly in place over this surface, slowly turn the shaft and see how AUX Input changes. If it moves between a voltage below 2V and above 3V, then it is time to look at the rest of the DRO. If it does not move this much, you need to improve the surface by making the black area less reflective and the reflective surface more reflective. You may also need to move the tach assembly closer to the rotating surface. If room light is getting into the sensor, you will need to shield the sensor more.
Let’s start with these tests and see where you are.
Rick
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I've tried Tach 2 in setip, I've tried edge finder connection set to tach in setup, still nothing but "INF".
I have done this
[Status [Tachometer
You can select between displaying Revolutions Per Minute and Surface Feet Per Minute with repeated pushes of the Z preset. When you press Enter, the display will prompt you to select which of the three displays you wish to use to show the output. Select by pushing the corresponding preset.
To turn off the tachometer display, enter the function a second time and press Enter. The displays will return to showing coordinates.
The software calculates the SFM using the RPMs from the tachometer and the selected tool from the tool offset function.
SFM = (RPMs x tool circumference in inches)/12”
where tool circumference is 3.14 times the tool diameter.
SFM is approximately equal to (¼ x RPMs x tool diameter).
The shortcut is to press and then .
See also [Position [tool offset
Page 34
I have done this
[Setup [Machine
When you enter this function, many sub-functions appear. Pushes of the Y preset cause the middle display to show these categories. You select which option within a category by pushing the Z preset and press Enter. Y zero preset enables you to go through the lists of options.
•[type of machine you are using: [mill or [lathe. The design intent here is that you define one “machine” as a mill DRO and the other “machine” as a lathe DRO. The defining of a
“machine” is done with the [System [machine function found on page 40.
• [flex selection [flex 1 or [flex 2. The DRO-350's circuit board has a port called AUX. The
software calls this input “flex 1”.The DPU-550 has a port called “tach 2” which software calls “flex 2”. These flex ports can be configured by software to be inputs when used with a
tachometer, or as an output, when driving a piezo beeper.
I'm getting the INF display with no tach cable attached to the DRO. I do have 5 volts at the connection and ground, the center pin is signal, have no idea how to do anything with that connection, other than plug something into it once I can any other reading than INF.
I sent Scott a question and he said he did not have time.
My DRO with scales is working fine, just thought I'd try the tachometer function. Making no headway. I'm guessing I have missed something in the setup.
Any words of wisdom?
Thanks
Roy
> From: rgsp...@aol.com
> To: dch...@live.com
> Subject: tach
> Date: Fri, 6 Nov 2009 06:22:39 -0700
>
> Roy,
>
> I am responding to your email off line because Scott is filtering my email
> and I don't like my speech limited.
>
> I built the tach and it works as advertised. You are right about
increasing
> the resistor's value: if you started with a 4.7K resistor and increased
its
> value, you could go to 10K. I recommend you make much smaller increases as
> you fine tune the tach. Steps of 20% would probably be better.
>
> My tach shines a light on a surface and responds to the reflection. I
found
> that this surface is a critical element in the operation of the tach. It
> must be very smooth with no drips of paint on it.
>
> I used the bottom of the V in a pulley. Using flat black paint I sprayed
> that part of the pulley. When it dried, I cleaned off a 2" long area
with a
> 3M pad which made it nice and reflective. I had one area with a drip of
> paint on it and had to re-do it because the display read high and jumped
> around a lot.
>
> I built the tach mostly for fun because my mill is belt driven with 12
> speeds. I measured the speeds once but after that it was boring since the
> answers don't change. I did buy a laser tach and have found it of more
> general use.
>
> Rick
>
> ---------------------------------------------------------------
>
> Good day.
>
> I'm collecting parts to assemble a tachometer for use with the 350/550.
>
> Reading the information Scott provides on his site, I see this statement;
> "Resistor R2 sets the sensitivity of the phototransistor. The value
of R2
> is directly proportional to the sensitivity of the phototransistor,
> increasing R2 increases the phototransistor's sensitivity and vice versa.
> Start with a value of 4.7K and adjust depending on ambient light and the
> amount of reflection provided by the rotating object."
>
> What does increasing the value mean?
>
> An example I could understand is, is 10K and increase from 4.7K?
>
> If anyone did not understand how much I do not know, this is a good
example.
> :)
>
> Roy
>
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Bruce Fairman
Rick Sparber
Bruce,
You wrote “and you what i think about the setup behavior.” Huh?
Rick
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Bruce Fairman
Rick Sparber
Bruce,
Thanks for the clarification.
=