eBay TB6560 Stepper Motor Driver Boards
Good Day All.
eBay now have the TB6560 Stepper Motor Driver Boards, in 3,4, and 5 axis.
I have ordered my self ones of the 4 axis versions.
I see that there is a topic about the eBay TA8435H Stepper Motor Driver Boards here but I wanted to start a new topic to stop cross posting or going off topic.
I have gone for the TB6560 over the TA8435 due to the fact that the TB6560 is ment to be able to run voltages of upto 34volts.
I am going to be running Astrosyn MY103H702 stepper motors in Bipolar Parallel, 1.4amp per phase.
Reading the datasheet for the TB6560 chip I can see that the current is set by current sensing resistors.
As I have not yet got my board I can only go by looking at the pictures, and if I am right the current sence resistors are, Brown, Brown, Silver, Gold, 0.11ohm 5%, If that is right we are looking at 4.5A, but the TB6560 chip is only rated to 3.5 amps peak.
Then you have the 6 dip switches, switches 1-2 are once again for current limit, 100%, 75%, 50%, 25%.
Are we looking at a current % of 3.0amps, 3.5amps or 4.5amps?
So how do I set up the board for use with my stepper motors.
Does anyone have one of thease board, or can anyone clear a few things up for me.
Thanks for your time.
Best Regards.
Caution about parasitic protection diode change
Hi Folks
Caution about those parasitic protection diodes.
Those diodes are getting hot due to catching the energy from the coils of the motors when the drive switches off the current to the coil. The magnetic energy induces a voltage in coil in the reverse direction to the voltage impressing the current at switch off. The reverse voltage increases until it is caught by these diodes. Take the diodes off and a very high voltage spike appears accross the output of the chip in the reverse direction to the normal supply destroying the output semiconductors. The parasitic protection diodes are high speed switching diodes and the speed of switching high currents is the important selection figure alomg with the thermal disipation for short pulses not the rms current rating.
I am correcting this as I got it wrong this morning. Using parallel connection gives less inductance and hence less kick back when the drivers are disconnected. The unfortunate bit I was thinking about was my own case where I need maximum powere at low revs where serial connection is best for my needs. That said if the motors are reving at speed then the diodes have to disipate the power generated in brining the shaft to rest.
Changing the type of diode for another with equal or better turn on speed will not have much effect on the heat in the diode. If the diodes are getting very hot then the back swing voltage from the coils contains a lot of power hence the heat. Increasing the diode forward current rating will not help as this is a diode package heat dissipation problem. Changing to diodes that have provision for an external heat sink is necessary to get rid of the heat from the diode in the middle of the plastic case.
If you change the mounting of the parasitic protection diodes you must pay particular attention to keeping the leads very short so that the lead inductance between the positive and negative ends of the individual diodes is short and the wire thick.
Sorry for the gloomy post. Good luck as the TBA6560 chip used with in its ratings is a low cost solution. If anyone can read the diode type number it would interesting as the diodes may be zener diodes with a rating of 40 volts or more used to clamp any positive coil swings induced by rapid conduction of the magnetic energy in the other coils.
Regards
Pat
Beware of your input voltage.
I finally had some time to test my TB6560 board from ebay today.(blue PCB) I purchased a 36V switching power supply to use with the board, but I didn't use it to test the board. I have a 3 amp variable voltage benchtop supply that I use when testing drivers. It has a digital display to allow me to see the amp draw. I started by testing the board at 24V. It powered up and it has 2 red leds to show power is on. Since they are near the 5V and 12V voltage regulators, I am assuming there is one for each voltage.
I attached an Automation Direct 276in-oz motor to the x axis rated at 2.8 amp. I had the board set at 100% current. With the board powered up, the motor wasn't on. I followed the instructions on the mini cd and configured Mach3. You must configure enable outputs in order to turn on the drivers. After configuring Mach 3, the motor locked up with power on as expected. I ran the motor at 1/8 and 1/16 step resolution and I tried all 4 settings for the decay. There is another led on the board that shows when the board is getting step pulses from the computer. This is no Geckodrive. Do not expect the motors to be quiet and vibration free. The motor ran the smoothest on the slow decay mode. When running the motor using the motor tuning screen, the board running 1 axis draws .5 amps from the power supply. The motor remained cool along with the bottom of the axis driver chip. I did accidentally touch the 12V regulator heat sink, and it was hot. I started testing maximum rpm, which was no where near the performance of the Geckodrive G540, but I was testing at half of the voltage that I run with the Geckodrive.
The next step was to turn up the voltage so that I could determine the top speed at the voltage that I was going to run at. I slowly turned up the voltage and tested the motor as I increased the voltage. Everything ran fine at 30V. I then turned up to 32V and smoked the driver chip. The silk screen in the board reads 12-36V. I let the board sit for a minute and then powered it up again. It maxed out the current on my test power supply. I am done testing.
Hopefully this helps others save their boards.
Best Regards,
Ron Chacich