Cheap (economical) Stepper Driver Boards

Thanks to you both Xylotex & Andypugh but I think I am a bit out of my depth here and have not explained myself very well. The following might be a clue:
I have one of those TB6560 boards to try but am only familiar with the 2 through 9 pin parallel port connections which are shared between four individual axis the only other connection being the Ov reference for the four pairs of step & Direction lines, I see no indication of this simple step & direction connection on these boards and do not wish to and am not capable of altering the configuration of my parallel port. i believe that these boards and also the L298N boards require logic from something like an Ardinuo/Raspberry Pi combination. I can find no data showing the actual point to point wiring and suspect that the simple connections I use on my four axis driver from I believe, Hobby Stores in America or the single driver boards from Routout are not possible with these driver boards. I appreciate that there are bright kids all over the place using these boards to drive all sorts of gadgets but This is one area in which I have very little knowledge. I am very happy with leaving such things as speed, acceleration etc to the excellent EMC2 software and just need to get the simple step and direction signals pumped into my steppers.

Although I guess I could simply wire up a spare stepper and apply 5V to various inputs without doing any harm..

Wow! Thanks for that Andy it make sense but I would never have associated CLK & CW with Step and Direction and was maybe vainly expecting to see a common reference termination. Bearing in mind my lack of knowledge and past pyrotechnic experiences I would have bucked at trying it out without guidance. But I will proceed with caution and report back in due course.
Thank again for your patience.

Hi Andy,
This is a little off topic but have you had or know of any one who has tried out a Three Axis board with these (LV8727 chip).
these are now going for around 60USD and have a lot of micro stepping settings all the way down to 128.
Thanks

Hi,

I took a look at the specs from one ebay listing. It said the unit had a maximum step rate of 15KHz. That might be quite useless with a step setting of 128 microsteps. For example, a Sherline has a pitch of 20 tpi. The motor will have 200 spr. That's 20 X 200 = 4000 steps per inch (no microstepping). 15KHz is 900000 steps per minute. Divide that by 4000 and you get 225 IPM. But that is at full step. Divide by a modest 8 (1/8th step) and you get around 28 IPM. That is useable for a Sherline. If you were to divide by 128 you would get less than 2 IPM.

The limitation of the drive chip used would be its maximum step rate. Perhaps you could go faster than what the ebay listing said, but 15KHz is the same as what the old TB6560 used, so it looks like that chip might be a remake of the older toshiba part.

My example was for a Sherline. If you were doing a direct belt drive type system where one motor rev. got you 3 inches of movement, then the 15KHz isn't a limitation after all. It depends on your specific machine as to whether 15KHz is a limitation.

Jeff

Thanks
Just checking to see if anyone had used these, the chip looks like it may be better than the TB6560 and the 6600, slthough that says nothing for the rest of the board circuitry.

This is a little off topic but have you had or know of any one who has tried out a Three Axis board with these (LV8727 chip).
these are now going for around 60USD and have a lot of micro stepping settings all the way down to 128.

In practice, any micro-stepping above 1/8 is probably wasteful, any additional smoothness and resolution lost against the number of pulses it takes to get anywhere.

There is also the matter of interpolation, the number of physical positions of rotor offset are finite and after that it is as good as the electronics of the driver.
The overall movement per batch of moves to make up one segment is undoubtedly accurate, but whether each interpolated move within that batch is exactly the same distance is another matter.

I think the numbers on the other drivers you mentioned relate to the chip, the 6600 being the later Toshiba chip.
The TB6560 drivers have a variable reputation, they do not all have the same pin outs, go bang if you exceed the input voltage and melt if you run them on the amperage limits in hot ambient conditions.
The T6600 drivers do at least seem to have better heat sinking, but I have not used them

regards

Hi,

I use the TB6600. They work quite well. I set them in 1/16th mode for my drive boxes which are mainly used for wood routers that have low pitch screws (2 tpi), so even at 16 microsteps, you still do not need a really fast pulse stream since the gearing ratio is so low. The TB6600 chips will do up to 200KHz step rate, but then, you need a really fast pulse stream to handle that.

While you may get no better resolution after about 10 microsteps due to the motor, you can achieve a smoother movement with a higher microstep ratio. It is a tradeoff between smoothness and speed. But if you have a pulse generator than can do 100KHz+, then higher microstepping rates (like 128 of the previously mentioned chips) would be good (IF they could handle that).

If you get one of those ebay boards that uses the TB6600 and has a large heatsink, but no fan I would suggest some things. Use a fan to help keep the chips cooler. The cooler they are the longer they will last. Also, don't run them at the advertised maximum current level of 5.0 amps. Often a maximum current level is to be only for a very short amount of time, not a continuous running level. The ebay boards say 5.0, but don't try to run them at that. The test conditions for the TB6600 use a maximum of 4.0A, so I would suggest not exceeding that, and still use a fan. And keep the running voltage below 45V. This would be the absolute maximum you want to try to run at. It only leaves a margin of about 10% to the abs. max. of 50V after which things blow up easily. Unless you have active voltage clamping in the power supply system, it would be better to run them at a max of about 40 volts. This allows more room for back emf voltages of a decelerating motor.

Jeff