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Author Topic: Pokey57CNC connection to G320 driver  (Read 4657 times)

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Pokey57CNC connection to G320 driver
« on: June 20, 2017, 11:27:40 PM »
What is the best way to handle the error/reset pin on the Gecko Drive G320 step direction driver?  This pin is both an input and output so always needs special attention.  Surely it must have been delt with b4 but I only see old stuff for other controllers and none of them look very good.

Besides the pin question above how can I invert the error signal on the Pokey57CNC so that it can do an estop on error.  I'm using the plugin for Mach3.  I get the error state on the plugin status but its inverted.

Re: Pokey57CNC connection to G320 driver
« Reply #1 on: June 23, 2017, 06:35:49 PM »
I have exactly the same question!!!   This seems like it should be simple, but I have tried many settings without a satisfactory solution.  Here is the link to the instructions for the 320X drive: http://www.geckodrive.com/support/motor-control-manuals/dc-servo-drives/g320x-rev-10.html

Re: Pokey57CNC connection to G320 driver
« Reply #2 on: June 23, 2017, 09:39:00 PM »
Thanks for looking.  Below almost works as I'd like.  This is from my previous G100 controller setup.  I think Pokey57CNC can probably do something similar without the diodes.
My goals:
1.  A physical start button on the machine that must be pressed until the G320s reset (approx 4 secs).  This dual button also latches a relay for the motors high voltage.  So the
motors and motor power can only turn on with this button.  Mach cannot turn on either of these functions, only turn them off.

2.  The Mach Enable button must be pressed at the same time after the G320 resets or Mach will become disabled.  So you hold the start until you see the motor error LED turn off
or hear the motors singing, then press and release the Enable button.  Mach will hold it on from here.  If Mach is not enabled or estops for whatever reason the motors will be disabled.  The high
voltage to the motors stays on when Mach disables in this way.
3.  If a motor errors want to know which one happened first.  That's why the diodes.  Otherwise 3 switches for start and 3 lines to enable.  Maybe since the Pokey57CNC has a motor
enable in each motor connector the diodes on the right aren't needed.

Any motor enable can be used for AX_ENABLE.  The resistor value needs optimizing. 

I haven't finished evaluating if the Pokey57CNC AX_Enable current limits are satisfied.  The AX_Enable pin says it can do 8ma.  This sinks ~16ma for a fraction of a second.
I'll post as I get more info and try a few other things.
Re: Pokey57CNC connection to G320 driver
« Reply #3 on: June 25, 2017, 11:06:59 PM »
CNC4PC has what he calls a master control board that is specifically made for this function. I just purchased one and will be setting it up in the next few weeks. I have long been frustrated with this "feature" of the gecko's and wish geckodrive would themselves make a very simple add-on device that simply separated the function for a number (say 6 max) of drives. Drive enable that looks for 5v or (24v preferrably) on the enable input, and has a 5 or 24v output that you wire into your estop.
Re: Pokey57CNC connection to G320 driver
« Reply #4 on: August 09, 2017, 06:39:02 PM »
Attached is the latest version if anyone is interested.  This works as desired and described 2 posts back.
1.  The diodes to 5V are still required because the Pokeys can't handle the current required to start the reset process.
2.  The 5V on the Pokeys motor connectors can't be used because Pokeys can't handle the current.  The 5V shown is from a separate
USB power supply.  This 5V is also used for the motor encoders. 
3.  The 330ohm resistor allows correct functioning without overloading the Pokeys enable pins.
4.  The 470ohm resistors are required for the G320 when using external power for the encoders.
Re: Pokey57CNC connection to G320 driver
« Reply #5 on: August 09, 2017, 07:53:15 PM »
Last post had incorrect relay connections.  Here's a redo.
Re: Pokey57CNC connection to G320 driver
« Reply #6 on: August 10, 2017, 09:18:42 PM »
Lowered the max current on my Gecko's so I could better test the above circuit and it doesn't work as desired.  The error out signal of the Gecko is not able to pull the line low enough for the Pokey Error signal unless the resistors (R1, R2 or R3) are greater than around 900 ohms.  However, the resistor won't be pulled low by the Pokey enable unless its less than about 690 ohms.

So as in my previous circuit for the G100 controller 2 diodes must be used for each axis.  Here's the latest.