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Power
Mar 18, 2019 10:09:50 GMT
via mobile
Post by rob75uk on Mar 18, 2019 10:09:50 GMT
Iv put my pc boards together and iv got 24v going to board but when I test the pot drivers there is no reading and when I turn the pots there is still no reading and getting very confused now . When I plug main power supply to board sometimes it sparks within the connector ?
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Power
Mar 18, 2019 22:07:30 GMT
Post by Bruce on Mar 18, 2019 22:07:30 GMT
Sparks are usually a bad indication of something. Make sure the stranded power wire is completely in the screw terminal. There may be a strand of wire that didn't get into the terminal properly.
Check the following for the stepper driver voltage adjustment:
1. Make sure the motors are unplugged from the CNC Shield board. 2. Make sure you have the 24VDC supply connected to the terminals on the red CNC Shield. 3. Connect the USB cable to the PC. 4. Make sure the battery in your multi-meter is good. 5. Set the multi-meter to read 2VDC. (Make sure it is not set to AC) The decimal should move to the left side of the display. 6. If you have alligator clips it will make this next step easier. Put your black lead on the screw (black wire) on the power connector to the CNC shield. 7. Place the red lead on the trim pot of the stepper driver board using a small metal screw driver. You should see a voltage range of 0.90 to 0.50 VDC on the multi-meter. turning the trim pot clockwise reduces the voltage, counterclockwise increases.
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skale
Junior Member
Posts: 57
Location: Newport NC
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Power
Jun 26, 2019 23:46:03 GMT
Post by skale on Jun 26, 2019 23:46:03 GMT
Bruce,
I’m not getting much of a variation in voltage on these pots. Nothing greater than .1 or 1. Is there a way to test my meter with the 24v DC, when plugged into laptop? If I put black on meter to black wire. Where can I put the red wire from my meter to get a 24v DC on the Red Shield.
FYI.. I replaced battery in meter and I am able to read a 1.5 volt from a normal battery. I have tried changing the from 20 volts, 2 volts, 2000 ma ...
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Power
Jun 27, 2019 2:47:51 GMT
Post by Bruce on Jun 27, 2019 2:47:51 GMT
To read the 24vdc you should have the red on + and black on - just match the wire colors on the CNC Shield. The meter should be set to 200Vdc. To read the stepper driver setting, use a range on the multimeter of 2000mV(dc) the reading will be 600mV (or 650mV for the CK) on the display. For a range setting of 2V(dc) the reading of the display will be .600V(dc) or .650V(dc)
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skale
Junior Member
Posts: 57
Location: Newport NC
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Power
Jun 27, 2019 15:01:41 GMT
Post by skale on Jun 27, 2019 15:01:41 GMT
Hmmm. I thought I tried that when connected to laptop.. and voltage = 0.
To read 24vdc on red and black connection, wouldn't I need to plug in power supply adapter to fan instead of laptop?
The light on the UNO board was blinking, so it's getting power. When I connected to laptop and power supply adapter to fan not connected, it starts with a fast blink then blink slows down.... I'm thinking the fast blink means something is loading ......
I will recheck when I get home.....
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rowiac
Full Member
Posts: 230
Location: California
Machine: M3
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Power
Jun 28, 2019 1:13:39 GMT
Post by rowiac on Jun 28, 2019 1:13:39 GMT
First, be sure you haven't connected the motors to the CNC Shield board yet. If you have, disconnect them. Next plug the USB cable into the UNO board and then into your computer. Then plug the barrel connector into the 24VDC power supply and plug it into the wall plug. Now you can measure the voltages of the stepper drivers. [Sorry--I just realized I duplicated what Bruce wrote above.]
If you are trying to test your meter to make sure it's working, you can get a regular 1.5V battery and see if you get a voltage reading from it. You can also probe the two screws on the green part of the barrel connector to see if you read 24VDC across them.
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skale
Junior Member
Posts: 57
Location: Newport NC
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Power
Jun 28, 2019 11:40:20 GMT
Post by skale on Jun 28, 2019 11:40:20 GMT
Thanks for the reply, rowiac
Reference: " Then plug the barrel connector into the 24VDC power supply and plug it into the wall plug. Now you can measure the voltages of the stepper drivers."
It was my understanding that we do not plug in barrel connector for power supply / fan if we are only measuring voltage of the stepper drivers (or pots on DRV8825).
I need help here. I confused.....
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Power
Jun 28, 2019 13:39:39 GMT
Post by Bruce on Jun 28, 2019 13:39:39 GMT
Please follow this procedure:
Check the following for the stepper driver voltage adjustment:
1. Make sure the motors are unplugged from the CNC Shield board. 2. Make sure you have the 24VDC supply connected to the terminals on the red CNC Shield and turned on. (Plugged into wall outlet) 3. Connect the USB cable to the PC. 4. Make sure the battery in your multi-meter is good. 5. Set the multi-meter to read 2VDC. (Make sure it is not set to AC) The decimal should move to the left side of the display. 6. If you have alligator clips it will make this next step easier. Put your black lead on the screw (black wire) on the power connector to the CNC shield. 7. Place the red lead on the trim pot of the stepper driver board using a small metal screw driver.
You should see a voltage range of 0.90 to 0.50 VDC on the multi-meter. turning the trim pot clockwise reduces the voltage, counterclockwise increases.
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skale
Junior Member
Posts: 57
Location: Newport NC
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Power
Jun 28, 2019 16:14:12 GMT
Post by skale on Jun 28, 2019 16:14:12 GMT
Bruce,
Thanks for your reply.
Reference,"2. Make sure you have the 24VDC supply connected to the terminals on the red CNC Shield and turned on. (Plugged into wall outlet)". So this is actually using the barrel connector into the 24VDC power supply. I missed this every time I read this and that is probably why I'm not getting a voltage reading on the DRV8825 pots. I believe prior to smoking my boards, I was getting a .65 volts from DRV8825 pots. After I plugged in the barrel connector into the 24VDC power supply, I saw white smoke and no voltage readings. So I'm not sure how I got a .65 voltage reading. Reference Carve-King instructions,"First plug in the 24V power adapter into the female socket, then plug the USB cable in from the Uno board to your computer." I was thinking the female socket was the other end of USB cable that the cable plugs into. So could the instructions be interpreted as "First plug in the 24V power adapter into the barrel connector." It threw me, maybe others?? Please confirm.
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Power
Jun 29, 2019 1:39:38 GMT
via mobile
Post by Derek the Admin on Jun 29, 2019 1:39:38 GMT
Yes skale, you could interpret it that way.
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Power
Jun 30, 2019 3:15:45 GMT
Post by Bruce on Jun 30, 2019 3:15:45 GMT
I suppose sometimes I assume too much. Sorry for the confusion.
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