How I fixed my Chinese TB6560 controller (updated)

[nodoutt]

so basically i just need to remove the 2 optos and connect each side with a wire or something.. Is this correct.. or will it mess something up.... I also read some were that I need to Replace the three timing capacitors (1000pf) with 100pf variants. is this also correct.. I understand some of this stuff and love learning this as well... I got the tb6560 chips out that were blown and ready to put in the new ones when they come... just want to get started running some stuff for the first time.. have been reading for a long time about this stuff.. purchased the BBFH because money was tight..
Thanks Jake

[Marc N Fournier]

OSC at 100pF.



Now had I been smarter, I would have run a capture with the 1000pF cap before.

Marc

[Marc N Fournier]

Jake,

Basically, you would remove 2 optos per axis; CLK (step) and CW/CCW (dir).

The Enable pin no difference makes.

The 100pF cap is the other good change.

Removing the regulators is another change worth the time.

Got your PM, was writing up something for you, when 5 things came up. Having way to much fun with the new 200 mhz/1G capture oscilloscope from China. I am not chicken am I. Dumb maybe.

Marc

[texaspyro]

Instead of just bypassing the optos with a jumper, also install a zener diode (5.6V - from the old opto input to ground) This will provide some protection against disaster without slowing down the signals like the opto does.

[Marc N Fournier]

Originally Posted by texaspyro Instead of just bypassing the optos with a jumper, also install a zener diode (5.6V - from the old opto input to ground) This will provide some protection against disaster without slowing down the signals like the opto does.

.

Interresting.

The optos are all ready on the wrong side of the buffer chip. They are between the 74HC17N and the pins of the TB6560) and not at the input of the parallel signal. So if anything bad comes down the LPT port, the 74HC17N is the first to received the shot. Since it is on the 5V distribution, any thing can blow from there.

Might as well put the zeners on the input side of the 74HC17N. The protection would be of greater benefit seems to me.

Marc

[texaspyro]

Originally Posted by Marc N Fournier Might as well put the zeners on the input side of the 74HC17N. The protection would be of greater benefit seems to me.

Yes, that would definitely be the best place for them (but I bet those '17s make dandy fuses). I put the zeners in the opto sockets since that was easiest to do when I was testing the mods. It turns out that modding the optos had zero effect on my board performance, so I went back to using the optos.

Frankly, NONE of the mods affected by board's ultimate performance. Nor did switching to a Gecko 540. I get the same max step rate. The Gecko is a very nice little driver and does add the benefit of the charge pump circuit.

[H500]

Originally Posted by Marc N Fournier I am no expert but the implementation of the optos here is so bad that they will protect the 74HC17N from the TB6560 chips, not your computer.

You are correct. I took another look at the schematic others posted and the design is much poorer than I remembered. Because they have a hc14 on the parallel port side of the opto and powered from the same 5v as the rest of the system, the opto is quite useless. If the tba6560 develops an internal fault that shorts the 34v supply to 5v, the optos would do nothing to protect the computer from getting fried.

Which scope did you buy?

[lodberg]

What are your settings for max speed (feed rate) ? Thanks a lot.

[H500]

The max speed depends largely on the power supply voltage unless your system happens to suffer from resonance. I'm not using one of these boards, but for comparison, with a 34v supply and 280 oz-in steppers on a SX3 mill, with preloaded ball screws, I can reliably move at 150 ipm on the x and y axes and 60ipm on the Z. I plan to use 45v, so in theory I should be able to do 200 ipm unless I need to tighten up the gibs for more rigidity.

[texaspyro]

I am using them on a MAXNC15 pile 'o crap mill. It has 1/4-20 acme lead screws and I can drive it at a whopping 12 (count 'em - 12) inches per minute with the stock steppers on 28V. With some other steppers (half the size of the stock steppers) I get 24 IPM. I am going to try some real steppers next...

[lodberg]

I'm using the TB6560 and I'm only able achieve 700-800mm/min (27.5-31.5ipm). My settings are: current 25% (off,off), fast decay (on,on), 1/8 micro step (off,off), 24V 15A power supply, 5mm Ball screw. I have tried with 28V, but that don't give any significant improvement.

Could it be the stepper motors I'm using that is preventing more speed? I'm using them in unipolar configurstion. However, I don't have the datasheet of the steppers: Nema 23, 1.8°/step
Type: 23LM-C005-29V
MINEBEA CO. LTD
Made In Thailand

I hope you can help me.

[doorknob]

Originally Posted by lodberg I'm using the TB6560 and I'm only able achieve 700-800mm/min (27.5-31.5ipm). My settings are: current 25% (off,off), fast decay (on,on), 1/8 micro step (off,off), 24V 15A power supply, 5mm Ball screw. I have tried with 28V, but that don't give any significant improvement. Could it be the stepper motors I'm using that is preventing more speed? I'm using them in unipolar configurstion. However, I don't have the datasheet of the steppers: Nema 23, 1.8°/step Type: 23LM-C005-29V MINEBEA CO. LTD Made In Thailand I hope you can help me.

I don't have any information about those stepper motors. Do they have six wires?

I'm not sure what you mean by "I'm using them in unipolar configuration" because the TB6560 is designed to drive motors using a bipolar configuration. So you must be using only four of the motor's six wires. That means that you must choose which of the wires to hook up, and which ones to leave disconnected. If the motor has a high winding inductance, then you may get improved speed if you choose a "half-winding" hookup instead of a "full-winding" hookup.

Reportedly, some of the TB6560 boards are miswired so that when they are set for 1/8 microstepping they are instead using 1/16 microstepping (and vice versa) - if that is the case, does it improve the speed if you change to "off,on" or have you already taken that into account? Are you using Mach3? What is your setting for steps per unit (mm/inch)? Have you verified that your axes move the expected distance for a specific number of steps?

Have you tried the 50% current setting? Does it make any difference in the operation of the motor?