Xylotex 4 axis with a different controller for Z

Hi I've had a 4 axis Xylotex on my converted X3 for a number of years now (Version 4) and it has worked faultlesly for all that time, however while it is more than adequate for the XYA axis it has always struggled a bit with the Z even with the assistance of a pair of gas struts either side of the head next to the dovetails, 600mm min. max with a double stack Nema 23. and 2:1 pulley ratio and the motor still sounds like its stuggling. However I've had 3 nema 34's kicking around for some time and have now fitted one of these. So the question now is is it OK to disable the Z axis from the Xylotex, and maybe reassign this to another axis in the future, and use two of the spare pins from the parallel port break out terminal for the other controller, if so which pins would be best to use. The controller is a Motion Controls 7amp unit and the software is linuxCNC. By the way the Xylotex runs the Nema 34 ok but still only gets about 700mm min. max. only to be expected really these motors require 5.2 amps and a a bit more voltage I've gone for about 50volts as aposed to 24 with the Xylotex. But they are great little boards as long as their kept nice and cool with a fan.

Thanks windy

Hi windy

after looking at this manual -
http://www.fabathome.org/wiki/upload...XS3525V400.pdf

unless you have already used them
it looks like you have 4 outputs from your printer port available on a screw terminal block on the xylotec board
( printer port pins 1, 14 , 16 and 17 )

using them will be easier than re routing the connections from pins 2 to 9 used by the 4 axis drivers on the xylotex board

Attachment 310600

if your printer cable has re-wireable D-type connectors
you can disconnect the wires from the printer port pins 6 & 7 and connect 3 new wires ( step dir & ground) for your new Z axis driver

this avoids making any mods to the zylotec board


John

Thanks John no I'm not using any of those I don't have limits or home switches the only pin I've used is pin 13 for a probe. What I wasn't sure of was wether these pin numbers are IDC socket pin numbers or the parallel port numbers its been a while since I was in the back of this thing. So if I use pins 16 & 17 that is pins 16 & 17 of the Paraport. Would I need pull up resistors do you think.This controller already has opto isolators so I don't think I need a break out board. Pin 1 is reserved for a e-stop I believe,which I don't have either, but may want at some point.

Thanks for your response I'll give it ago, Windy.

Hi windy

yes , pins 16 & 17 are on the 25 pin D-type

Attachment 310606


John

thanks John I'll give it a go tomorrow if I can again thanks for your assistance I'll let you know how I get on. Of course I've got to add this to the Hal file yet.

Windy

Hi windy

you have not indicated what new drivers your going to add to drive the new motors

looking at the photo in the zylotex manual , it looks like an octal buffer (74xx244) is used to buffer the step and direction signals to the 4 stepper drivers on the xylotex board

the unused connections at the screw terminal block will be un buffered connections directly connected to the PC printer port

without any details of the additional stepper drivers and how you connect the step & direction signals
it is not easy to decide if you need to add any pull up resistors

with a driver like DM870 with opto isolated inputs you have a choice

either connect the step+ and dir + to the +5V from xylotex board and the printer port terminals to step- and dir-

or step - and dir- to GND and step + and dir + to the printer port

john

Yes John it is the DMD870 I'm only adding the one because as I said the Xylotex is more than capable of driving the XY and A axis I can't stop the table against the motors it tends to push the mill sideways if i try Iv'e been more than happy with this board. I think Iv'e had it about 8 years now possibly a bit longer.

Windy

Sorry John missed a bit off the last post. I thought that if the port terminal block on the Xylotex comes straight from the port it would already be at 5v when it sends a pulse to the driver. This is on a PCI parallel port not the mother board port I did this to give some protection to the motherboard if things went wrong (rightly or wrongly). The mother board is a mini ITX, a intel I think dm510 or something like that, so that port is there if ever I decide to add limits, homing, Estop etc.

Windy