[dbtoutfit]

My Question to supplier:

Hi I am using your DM542T driver and 425oz stepper combo on my new cnc machine.

I can not seem to get the motor to spin the other direction. It only seems to spin on signal high (3.3v) to the dir pin but not signal low 0v on the Dir pin.

I am currently waiting on my breakout board so I have the driver wired directly to my parallel cable for testing.

I have the drivers set for 10micro steps, full current and 3.0 amps on the dip switches.

I have 5v+ going to Pulse+ and Dir+. I have the logic Pulse pin going to Pulse- and the logic Dir pin going to Dir- on the driver.
ENA+/- is not connected.

All pin configuration are correct in Mach3.

All lights are green on the drivers.
All the motors polarities are correct per the motor manual back to the driver.

I assumed at first the motors would not turn the other direction due to only getting 3.3v high signal but after testing I find the motors spin with 3.3v but not low signal 0v.

Their Reply:

The signal input of the driver is generally isolated by the diaphragm, - grounding, dir signal should be able to provide a few milliamps of current should be able to work.
for example, your IO port is open drain mode, then not, set to push-pull mode to High level output current.
Also note that the program is logically the opposite.

TIA

[tommylight]

TIA

Two options:
Change the wiring to all negatives to ground and positives to bob/paraport.
Since you are using mach there is timings to be set somewhere at the motor tuning screen so set the timing to 15000 or max posible.
I do not use mach3, i use Linuxcnc.

[john-100]

If you connected the stepper driver to the printerport like this with a common +5V
it should of worked
As the PC port can sink more current to ground than it can source current from the ports +5V or +3.3V supply

Attachment 425208


To test to see if there is a problem with the printer port pin connected to the stepper driver - DIR terminal
or the stepper driver

first test with the drivers -DIR terminal disconnected
then try hard wiring the - DIR terminal to the printer port GND

If the motor direction is now reversed with the - DIR terminal grounded
either the printerport is fauly or the wiring

Attachment 425210



using a breakout board with a 74LS245 buffer can sink 24 mA or source15 mA for example

you could either wire the driver with a common +5V to the + step &+ dir
or common GND to the - step and - dir

John

[dbtoutfit]

Thanks guys for helping. I am loosing hair at this point.

Take a look at this and tell me what you think.

For some reason I am getting 5.5v hi and 3.3 low signal on the dir pins from the new BOB that came in today. (man Geckos were so much easier to get working than this)

Thanks for any input.

[dbtoutfit]

So all I had to do is move the 5v from the external sensor terminal to the Common Anode (DC5V) terminal and that got the low dir signal to drop to 0v and now my motors turn both directions!

[john-100]

Great to see you have it working