DM860A turns only one direction

Hi,
I'm building plasma CNC controlled by LinuxCNC 2.8 and I have encountered problem on DM860A drivers.
I have 3 drivers controlling X, Yleft and Yright motors. Motors on X and Yright are spinning only one direction.
Motor on Yleft is fine (moves both directions).

All drivers are set the same way (switches SW1-SW4 are OFF, SW5-SW8 are ON) and are connected to the same type of PSU and NEMA34 motors.

When I move driver DM860A from functional Yleft to control X or Yright then they do work OK. For me that suggests that signals from my breakout are OK, wiring to motors is OK and PSUs are OK.

Motor on Z-axis is controlled by a different type of controller and it does work OK as well (so I'm guessing timing values are OK).

Am I very unlucky and I have two faulty drivers?
What can I check to further diagnose the issue?
Can I connect +5V directly to DIR and check if this will trigger change in the direction?
Should I adjust some specific timining settings in the config?

radek_marko wrote: What can I check to further diagnose the issue?
Can I connect +5V directly to DIR and check if this will trigger change in the direction?

Set the timings to 5000,5000,20000,20000.
Do connect 3.3 to 5V and check if that changes direction.
If it does not, open the drives and check the optos inside for "cold solder".
Had one of those lately, a quick soldering session and it works perfectly.

OK, mystery solved.... ish...

So, the voltage on DIR when connected via DB25-1250 and wire is not connected to DM860A then the voltage stays at 5V (no-load voltage). When the same signal is connected to DIR on DM860A the voltage is dropping to approx. 2V and it drains 30mA (60mW in total).
When I've connected 5V directly from PSU to DIR on DM860A the voltage does not drop and it drains approx 16mA (80mW total).

What's strange - one of the drivers is happy to accept this low signal to change the direction, but others do not

Now I'm checking options of higher voltage and current for DB25-1250 board output. If I remember right I could separate 5V+ and Vdd on this board and increase Vdd to e.g. +12V.

Edited...
There is 1k resistor and EL817 transoptor. On the output side 30mA over 1k Ohm resitor results in voltage drop to 2V.

forum.linuxcnc.org/media/kunena/attachme...BOB1205schematic.pdf

If I will remove voltage jumper JN2 and apply +12V to Vdd then it should work :dry:
As per attached screen - for 5V Vcc the resistor should be 0Ohm, as 1k resistor is already on DB25-1250 board I will apply +12V and DM860A should detect direction without any problems.



The strange thing is that it spins without any problems - and the voltage for pulse is coming through the same combination of 1k resistor and EL817C transoptor :dry:

Try wiring the drives to +5V common, see if that works better

With 5 volts you should not be drawing anything close to 30ma. I'd be investigating further before supplying 12v.
A simple 270 ohm resistor across 5v should only draw 18ma.
1k should draw 5ma, how 1K, 270 ohms and a Opto LED is drawing ~30ma makes no sense.

I'm thinking there maybe an issue with the output on the breakout board.

I have wired it with common 5V - I've spotted that it should be NPN switching on the schematics and now it does work as expected.

Now I've encountered a new problem in my configuration of XYYZ - dual Y, but I will post the question in the relevant thread.

Tommylight - thank you for your help and suggestions.