Is there a way to up the driver current on the tx14207 stepper driver from my CNC 604
Hi CNCzone community,
I have a CNC 6040 router with the tx14207 stepper driver. The best accuracy I got so far is 0.6 mm. Someone on YouTube explained to me that my machine doesn’t hold the microsteps because the current on the motors is to low and that upping the driver current would help improve the accuracy.
De tx14207 stepper drivers have dip switches (see photo). Can the current be adjusted with those switches? And if this is the case, is there any information around about the combinations?
Re: Is there a way to up the driver current on the tx14207 stepper driver from my CNC
A bit late to the party but this might help.
Like you, I got a Chinese CNC 6040 with TX14207 controllers and TX14175 parallel port interface and had missing steps issues. Put to one side for a year!
The first thing I noticed is that the chip on the TX14175 that received data from the PC was an 74HC245. This is designed for CMOS 5V signalling whereas the parallel port uses TTL. The part should be changed to a 74HCT245 for best noise immunity. It's surface mount so a bit tricky if you don't have the skills. That said it didn't seem to be causing a problem.
The other thing I noticed, and it took me a while to twig as it only happens until the controller boards warm up, is that the steeping was very irregular when the direction signal was high, I put a scope on the TX14207 opto isolator outputs and found glitches on the direction signal. Yellow is step, blue is dirn,
Nasty! Also the supply voltage to the GAL16V8 and the TB6560 was set to 3.3V. The data sheets for these specify 4.5 to 5.5V. The reason they went for 3.3V, I think was due to the fact then when stepping the 3.3V power supply is poorly regulated and rises to well over 5V so they used 3.3V to prevent damage to these chips. The downside is that it causes the glitch on the dirn signal. I replaced the 220uf 16V capacitor with a 1000uF 16V ( 6.3V or 10V would be OK). This improved things greatly:
Next I changed the 3.3V supply to be closer to 5V by adding a 1.2K resistor between pin 4 and the pad of the switching regulator LM2576. This gave me 4.75V. These mods should address ant skipped steps for the above reasons. I used a 1206 size SMD resistor.
If you want more current you can change the big white 0.22 ohm resistors for a lower value. The lowest you can go is 0.15ohm so I added a 0.5ohm in parallel to each one do that.
Re: Is there a way to up the driver current on the tx14207 stepper driver from my CNC
And here's a coda to the above changes I made to these TX14207 boards. I set up one of them to do one step left then one to the right on the bench. Ran for hours and checked to see of they had drifted off. One board was troublesome. I added filters to the pulse and direction signals to the controller chip and small high frequency capacitors on the power supply pins. Nothing seemed to help and it was impossible to capture the exact area even on my scope to debug it any further
I gave up and bought three TB6600 off the 'bay modules for about US$20 the lot. Work perfectly. Wish I had done this at the outset.