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  1. #649
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    I suggest the extra 74hc14 in the step line might not be the right solution. Perhaps a better one would be to add the inverter into the dir line.
    I suspect the error in counting is happening at some direction change transitions (as discovered by another poster)...

    But obviously only you can determine if this is true for your board.
    The advantage of not doubling up on the step signal is to continue to trigger the step on the rising pulse as per spec sheet.

  2. #650
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    jumper all optos

    what would be the result of removing ALL the opto couplers and installing jumpers on a 4-axis blue controller?

    I've got a stepping pattern showing up in arcs and curves and have not been able to eliminate it with any settings in Mach3.

    Gcode is segments for arc moves, but the stepping pattern does not correspond to the points on the curve, shows up on diagonal moves as well.

    It almost looks like the X signal is executed milliseconds before/after Y signal in a gcode line like:

    G1: X75 Y87 F1000
    G1: X85 Y97

    Just curious about the other optos, I have the corresponding ones jumpered as posted earlier in this thread.

  3. #651
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    Quote Originally Posted by Dirty Steve View Post
    what would be the result of removing ALL the opto couplers and installing jumpers on a 4-axis blue controller?
    Unless the opto's 5v power supply come from the computer, they will offer almost no protection. You will lose nothing by removing them. It might be necessary to invert the signals in Mach afterward.

  4. #652
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    Actually running on a laptop with 3.3v parallel port without an issue, except for the stepping pattern.

  5. #653
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    Had enough

    Hi, Wow, what a great thread! I read every post and thought I'd briefly share my experiences for what it might do to help others. I purchased the four axis blue board from ebay recently for a non-CNC application (sorry if I offend). The board worked OK out of the box. I couldn't see any markings on the caps so I don't know what was installed. However, without any mods I was able to drive a stepper at 600RPM (1/2 step) reliably (see note below), which meets my needs. The DIP switch settings were 101110 when shipped and this seemed to be the only setting that did not cause constant bad high-pitched buzz noise (even when enabled but not rotating) and resulted in the most reliable operation. Interestingly, when I stepped the motors one step at a time even at this setting the buzz was still bad every other step. However, my wife could still hear the buzz even on the "even steps", but it was much better than the "odd steps". I could actually use this to tell if I was dropping steps. If I stepped cw 1000 steps and then ccw 1000 steps and the noise changed then I knew I lost at least one step.

    My stepper specs say that running the motor in bipolar mode should not allow me to run as high as 600RPM even with no load, so it looks like the board is doing what it needs to do so far. I'm still nervious about the power-up sequence and frustrated that the input isolation is not what it should be, but it looks my luck is better than most with this board.

    Again, I really appreciate all the great discussion on this thread.

  6. #654
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    Quote Originally Posted by theforce2000 View Post
    My stepper specs say that running the motor in bipolar mode should not allow me to run as high as 600RPM even with no load, so it looks like the board is doing what it needs to do so far. I'm still nervious about the power-up sequence and frustrated that the input isolation is not what it should be, but it looks my luck is better than most with this board.

    Again, I really appreciate all the great discussion on this thread.
    That's great it's working for you, apart from the known issues with these boards, what a lot of people also find using the various iterations of these boards, is that once the spindle is powered on, the noise that's fed back into the circuit renders the system unusable. Given it appears to be working for you now, if your not planning on using it with a spindle, you may well be exempt from the troubles!

    cheers,
    Ian
    It's rumoured that everytime someone buys a TB6560 based board, an engineer cries!

  7. #655
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    I recently purchased a chinese Blue 5-axis board (6560AHQ). It has www.hyu68.com screenprinted onto the back.
    Its very similar to the three axis but appears to be a new revision. It has an extra 7474 on it and I thought YAY! a fix for the rising clock slope problems on step pins .. but NO!!. its just used for the LEDs

    So I pulled out all the chips and pinned out the circuit. I think its the same circuit from post 1 but IMHO that circuit may be wrong. I need someone else to check a 3-axis board to see if its totally different. (check the images below)

    Anyway here's the change. Instead of a 150 ohm resistor between the inverter and the opto, its got two. This is so the signal from the PC can be routed straight out to the display board. But the extra resistance explains why triggering is so weak on the opto. The end result being there is only a 0.4 volt pulse for the opto to trigger on .
    The original diagram shows this second 150 ohm resistor going to the display board (and the manual control pendant).

    So I wondered what else was different and Pinned out the rest of the board.




    When driving my board I kept getting the X and B (or D) axis LEDs lighting up at the same time. Turned out it was my Pendant board doing this. My pendant board worked fine as a manual control as long as the PC was not connected. So for the longest time I left it plugged in. But the PC connection only started working reliably when I pulled the pendant out. The keyboard (whether using mach3 or linxcnc) works fine for manual control so I'm throwing my pendant away. I also have a display board. This worked erratically when driving using the PC but perfectly from the manual pendant. I'm leaving it connected as it also works well once the manual pendant is removed.

    I consider this a good example of it works in testing but not when connected to a real system. I'm sure they use this to test them at the factory but not with a PC port... As you can see from my scope traces I'm getting adequate driving voltages from the PC port.

    Another difference in the 5-axis board is the combining of all the enable pins. With 5 axes you're running out of control pins. So they've joined all the enables into a single pin. This means there is one opto on the board that is not used. Well actually its input is tied to asm (A axis, Step pin, Manual connection (DB15)) but see the picture. Cutting a trace will free it up. If you're enterprising you could hook it up to pin5 on the input connector and get another limit switch pin for axis A or B (C,D) axis. Pin 15 on the PC port DB25 is also not used. I haven't done this yet.

    So it looks to me like:
    - if you don't need the pendant and the display, then jumper right over the opto from the 7474 pins direct to the 6560 driver. But more of a summary about that in my next post. I chose to keep the optos in and use the display board. so YMMV.

  8. #656
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    An encapsulation of what I have been able to glean from the 57 prior pages. This information was invaluable in getting my 5-axis system to work.
    With thanks to you all...

    Essentials:
    1. Never plug a motor in when its powered up. The poor grounding (note4) may destroy the 6560 chips.
    2. Check that pin 25 for every driver IC is not shorting. Shorten it if it is too long.
    3. Check dip switches all work. Use a multi-meter on the back of the board to check for short when switch is on. Some have been found to be faulty.
    4. Ground the heatsink for each TB6560 through its mounting screws. Solder a wire to the large ground plane next to the small cap (there is a via there to use) and then wrap the other end around a screw on each TB6560, or use a solder tag. Can also use pin 10,15 but not 6 (5V earth) for grounds. Pins 10,15 also route to the stepper motor pins for convenient soldering.
      In the current design, there is a danger of blowing all chips if one goes bad. Adding the grounds helps protect them all.
    5. Add a protection diode across the spindle relay coil. (Diode bar on the +12V side). There is no protection here. A diode will help to prevent noise and protect the transistor.

    6. Disconnect the spurious current save feature. This generates extra pulses and is not useful. The simplest way is to remove the 10k resistors on the back of the board. These are located differently for each design but the 10k and transistor will be very close to each other and near the top of each driver chip.
    7. Pin 7 on driver chip has a cap that sets the internal frequency. The only value that is tested to work, and calibrated for the three decay modes, is 330pf. Replace the 1000pf which is installed. Forum members have tried several values (including not using one at all). All offered improvement over the stock 1000pf.
      However the data sheet clearly indicates that for speed decay and microstepping the only supported value is 330pf. (The supplied 1000pf value is too high and generates audio frequency noise).
    8. Cleaning up the pulse to Clock(Step) and Direction pins.
      The pulse from the optos is very slow on rise time. The chip triggers on the rising edge so this pulse needs to be better shaped. The negative edge is good but the chip ignores that.
      Two methods:
      • EITHER bypass the optos for step signals by removing them. Put a link between pin 2 and pin 4 of the step optos.
        This has the negative side effect of removing the tenuous isolation benefit of the opto but will not effect counting if using a display board.
        The on-board LEDs will display properly.
      • OR add an inverter after the opto to clean up the pulse shape and invert it for proper trigger on rising edge.
        This will maintain the opto isolation but you will need to set the step to active high if using mach3.
        Unfortunately as a result of the mach3 change, the on-board LEDs will now be on all the time. If you have the 5 channel board, with the extra 74HC14 driving the LEDS, then you can jumper this inverter to get the LEDs back.
        But the LEDs are a crude indication of whether an axis is working or not so you might simply choose to ignore them.
      • OR jumper the opto and resistors out completely. This will deliver a nice clean pulse but leave you without manual pendant and external display control (both of which use the DB15 port). You won't have LEDs flashing for each axis either. The optos will no longer be providing the tenuous isolation support.


      Changing any of these will have an effect on direction pulse also. We have changed the timings between signals. There will be a delay between direction and step pulses. This may cause a +/-1 problem if changing direction a lot.
      So if you jumper the opto for step - you should jumper it for direction also. Enable is less of an issue and does not need to be changed.

      You have more control over these timing issues if using LinuxCNC than you do if using Mach3. This pulse delay will only affect you if using very fast pulses. You can make a test by stepping and changing direction many times in a row. move10, change dir, move10, change etc. The end result is the stepper should not have moved after many pulses. Try 1000. If it has moved then you have a delay that needs fixing. See Checks section below.


    Optional changes:
    1. Increase diameter of sense wire to better return current to the chip for current protection.
    2. Change sense resistors to proper values for your stepper motors. E.g. 0.47 ohm for 1 amp motor. Turn current dip switches to full.
      The current dip settings are not supposed to be the primary way to control motor current. Instead it supposed to be the sense resistors, with the dip switches being secondary and therefore matched to the motor.
      Proper decay made behaviour requires correct sense resistor selection. This sets maximum motor current. I = V/R. Where reference V=0.5V
      • so R=0.5 ohms = 1A, 0.25=2A, 0.15=3.3A
      • e.g. specific motor 57BYGH56-401A rated at 2.8A = 0.18 ohm sense resistor. (3-5W)
    3. The 12V regulator (7812) is close to being overloaded and runs very hot. Lighten the load by adding a second 7812 direct from the incoming DC to drive the fan.
    4. Startup order is bad. Do not use a switch on the power line coming from the power supply. Instead enable on/off by turning on the power supply itself. This will help a little as modern supplies have a soft start. But fundamentally you can expect breakage of 6560 chips when powering on or off. This is not widely occurring but its a design flaw.

    Manual Pendant:
    • The display board may not reliably read pulses from the 25pin computer port unless the manual pendant board is removed.
      The board places too much load on the circuit and pulses are not read if it is attached.
    • The manual pendant board is useful for initial testing but once installed with EMC or LinuxCNC, the keyboard should be used for pendant operation instead.


    Replacements:
    The replacement design for this chip is the TB6564AHQ also called THB6064AH. It handles 40V instead of 30V and does not have startup sequence problems. It is not pin compatible with the 6560HQ.
    Two good designs, reasonably priced, from:
    ldt THB6064 Driver kit and:
    THB6064 MassMind Stepper Motor Driver Kit

    Note Geckodrive Step Motor Drives Gecko drives FTW (e.g. G540) but expensive.
    (I am not associated with any of these.)

    You're going to spend a bit of time getting the blue boards to work. Even using these tips. Your time may be better spent by instantly moving to a better chip/board design. Many users have found this to be true.


    Checks:
    • Is your computer putting out pulses on the right pins ?
      You need to set your bios to ECP+EPP. Bidirectional is not the right setting.
      Here is a simple procedure for testing your pins using multimeter. (use jog control and check direction pins with trial Mach3 program).
      [ame=http://www.youtube.com/watch?v=uglCm_qsojk]CNC Electronics 5 -Testing the Parellel Port.wmv - YouTube[/ame]
      If the direction pins are working there is a strong likelihood that the other pins are working.
    • Here's a refresher on the DB25 Parallel port.
      Parallel port pins diagram. Inputs and outputs.

      Its worth noting that on some(most) blue cards Pin15 is not used.
    • Testing for loss of pulses
      Do 1000 +20,-20 steps. if there is a delay between change direction and step pulses you will see the stepper drift off from zero (in steps of 20) after a lot of pulses. This means the delay between changing direction and sending the step pulse is not large enough, or your signals are not well shaped or possibly inverted. If the offset is not in multiples of 20 steps then you may be losing single pulses, in which case your timings are probably too fast for your computer. There is more fine grained control over this in LinuxCNC than in Mach3.

    I found this thread incredibly useful. Thanks to all who have contributed.

  9. #657
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    Quote Originally Posted by Neon22 View Post
    An encapsulation of what I have been able to glean from the 57 prior pages.
    Thanks for the summary! It was really hard to tell working fixes from the other ones until you posted this.

  10. #658
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    How I really fixed my Chinese Control Board

    I have used a Chinese TB6560 control board for about 3 years. I made all the fixes in one form or another and the board performed fairly well except when I was running very long programs for etching PC boards when it would miss a few steps and lose registration. I had a lot of confidence in Toshiba, I don't believe they would keep putting out a chip that didn't work so I looked first at the outputs from the parallel port. These looked good and clean. I then looked at the inputs to the 6560. Here is where the problem was. The signals were noisy and the low was right about 0.8 volts which is the max spec low for the chip. I looked at the board schematic and the whole buffer circuitry is backwards. Opto isolators should have come first and because they degrade the signal the 74HC14 should have been after the isolator to clean the signal up again. I started looking at why the signal needs to be buffered in the first place and decided it didn't. The output from the parallel port uses 5V logic and so does the 6560. There is no need for a buffer.
    I removed the 74HC14s and the 9 opto isolators for the XYZ signals and removed the IC sockets they were in. I then wired jumpers from the input pads where the 74HC14s came out directly to the output pads where the isolators were effectively connecting the parallel port directly to the 6560 for the signal lines. Presto everything worked great. I have run several tests and made several PC boards since without any indication of missing steps.
    If anyone else is having trouble with this board I suggest you give this a try.

  11. #659
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    I've read all this thread because I'm another person with this driver. I know all of the main hacks that I have to do but my board seems to be different from yours and so I would like you to please confirm what I have to do (click on the pictures to see high res images):





    Replace those caps
    Remove those resistors
    Ground the drivers
    Remove the Opto Isolators and place jumper wires
    Use a diode on the relay
    Use external power to drive the cooling fan.

    The CNC driver arrived in such a bad shape ( one corner partially smashed, full of dirt and some grease, broken screws and the parallel port was a little bent) that I'm affraid of power it on with my stepper motors so I want to make sure that I'm taking minimum risks of killing my steppers.

    My stepper motors are NEMA 32 3.1Nm that will draw 2.1A in series (more info here: http://cnc4you.co.uk/resources/60BYGH301B.PDF ) and will be powered by a 24v 15A power supply.

    Should I be worried?

  12. #660
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    Quote Originally Posted by Capnden View Post
    I have used a Chinese TB6560 control board for about 3 years. I made all the fixes in one form or another and the board performed fairly well except when I was running very long programs for etching PC boards when it would miss a few steps and lose registration. I had a lot of confidence in Toshiba, I don't believe they would keep putting out a chip that didn't work so I looked first at the outputs from the parallel port. These looked good and clean. I then looked at the inputs to the 6560. Here is where the problem was. The signals were noisy and the low was right about 0.8 volts which is the max spec low for the chip. I looked at the board schematic and the whole buffer circuitry is backwards. Opto isolators should have come first and because they degrade the signal the 74HC14 should have been after the isolator to clean the signal up again. I started looking at why the signal needs to be buffered in the first place and decided it didn't. The output from the parallel port uses 5V logic and so does the 6560. There is no need for a buffer.
    I removed the 74HC14s and the 9 opto isolators for the XYZ signals and removed the IC sockets they were in. I then wired jumpers from the input pads where the 74HC14s came out directly to the output pads where the isolators were effectively connecting the parallel port directly to the 6560 for the signal lines. Presto everything worked great. I have run several tests and made several PC boards since without any indication of missing steps.
    If anyone else is having trouble with this board I suggest you give this a try.
    I was writing my post almost at the same time that you posted this so I didn't see it at that time.

    I would like to try your approach first since it does not involve to (de)solder anything and is easy to rollback. Could you please have a look at my images and tell me exactly how to place the jumper wires?

    Thanks!

Page 55 of 74 545535455565765

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