Slaved axis, 2 steppers on Y axis with a PLC4x-G2 ? what about the XP23 connector ?

[pierantoine]

Hi,

i have 2 steppers on the same axis with AM882 drivers,
I could use the slaved axis in Mach3, but

1 - is there a solution to slaving an axis in hardware with a purerelogic PLC4X-G2 Breakout board ?
i know that i can hardware slave a stepper with a pmdx-126 http://www.pmdx.com/PMDX-Forums/index.php?topic=101.0

2- is it better than using the slaved axis in Mach3 ?

( why using PLC4X-G2 : is cheaper and the VFD is included, and the motion controler PLCM-E3 can be added in the future for less than a SmoothStepper).

3 - I've read on the manual of the PLC4x-G2 http://www.zappautomation.co.uk/productattachments/index/download?id=99 that i can do something with the XP-23 expansion "2 step motor drivers can be additionally connected through expansion socket XP23 if it is necessary" But how ? do i need a second PLC4X-G2 or an expansion board ? because i don't see any step and dir on XP23 connector ?

Thanks for your help.

[Boyan Silyavski]

Hi,

3 - I've read on the manual of the PLC4x-G2 http://www.zappautomation.co.uk/productattachments/index/download?id=99 that i can do something with the XP-23 expansion "2 step motor drivers can be additionally connected through expansion socket XP23 if it is necessary" But how ? do i need a second PLC4X-G2 or an expansion board ? because i don't see any step and dir on XP23 connector ?

Thanks for your help.


google translated from russian forum:




Actually, not clear with that with XP23 -
12 and 5 - as I understand it ... and power outputs a current limitation? What can I hang here?)))
XP21 pin 1/14/16/17 - is Input or Output? MLM depends on the settings of the software? What napruga and the current max?
IN6 - simply duplicated XP30 aka e-stop?
ENABLE - ummm ... it's here for what? output signal? or what? :?


Well, about the connection DSHD - I have only 5 input on DSHD, sootvetsvtenno, you can take it any contact + step | + dir | + enable?


Well, a little proposal for revision - and make outputs XP5-8 XP31-36 based on IDC-connectors ... very much do not want to board something to solder, such as connectors for a week I can not find ... :(






Hello.
The XP23 connector has outputs for connecting pins 1/14/16/17 5th and 6th axes or for other needs.
+ 5V is used to connect these pins as a general alarm output (connection sourcing).
+ 12V is used.
The connector XP21 pin 1/14/16/17 is output, the maximum current depends on the LPT port on one computer is 5mA, 20mA other.
Enable - an output signal for controlling the driver.
When connecting the driver circuit for sourcing + step / + dir / + enable this general conclusion + 5V.

[Boyan Silyavski]

and this one also https://translate.google.es/translate?sl=auto&tl=en&js=y&prev=_t&hl=en&ie=UTF-8&u=http%3A%2F%2Fwww.purelogic.ru%2FForum%2Fviewtopi c.php%3Ff%3D49%26t%3D5772&edit-text=&act=url

[pierantoine]

Hi thanks again !
i'havent seen this one ;-)

[PAULRO]

Hi Piertoine, i have installed a PLC4x-G2 BOB and a PLCM-E3 motion controller. i don't think the axes can be slaved through hardware. i have slaved axes using Mach. I had great help from Jazz with setting this up. i'm still trying to configure the spindle control from MACH and i have an issue with the on board relays but Jazz is helping me with this also. i don't have a fourth axis setup but would like one when i get to grips with the standard X,Y,Z, functionality . i tried to join the purelogic forum but haven't had clearance yet.

[pierantoine]

Hi,
You are right, i have the confirmation from Purelogic that there is no hardware solution to a slaved axis solution and that "Usage of one channel for two drivers-motors controlling" But i think that the AM882 requires to much current for this solution.
but there is a topic where i could read that there is a big interest un doing this in mach3 to auto-squaring the gantry with the limit switchs.

I will also have a problem with the relay because i have a 2.2Kw spindle wich seems to much for the onboard relay... maybe a relay controlling another one with better current specs.

"If it can helps here is some infos that i've received :
In XP23 connector there are pins control outputs, PWN, enable.
When necessary these pins can be assigned for extra axis control. (it can be slave as well as independent)
You can also connect up to 6 axes to PLC4x-g2 (instead of the relay and spindle speed control).
If there is no such possibility, there is a perfect solution such as PLCM-E3 and PLCM-B1."

[JAZZCNC]

Using one signal to control 2 drives is not recommended. It as nothing to do with the current setting on the drive it's to do with Resonance and how the drives compensate for resonance.
If using just one signal then resonance compensation on one drive can throw the other into resonance and vise versa. This can lead to poor performance, stalled motors or lost steps or mixture of all 3.!!

It's standard practise to use the Limit switches to square the gantry.
The way Mach and most Motion control cards home is to decouple the slaving feature while homing and drive each motor individual but simultaneously towards the home switches. Which ever switch is triggered first that motor is stopped and reverses off the switch while the other keeps going and does the same. When both motors find a switch the homing is finished.
In practise this is very difficult to see. If Gantry is square and switches are correctly set then Both motors will stop/reverse exactly together in one seemless action.

Also the Relay will be fine with 2.2KW spindle. I think you maybe don't fully understand what the relay is used for.?

It's only used to switch on/off low current signals that control the VFD. You don't use it to turn on/off power to the VFD.
Cutting power to the VFD while spindle is spinning is not recommended so never do this. Always stop the Spindle with the VFD Stop input then remove power.
Also NEVER put any switch or Relay between the VFD and Spindle other wise you risk damaging both.

Paulro's problem was a simple set up issue and slight wiring problem go check is thread to see why.

[pierantoine]

Ok, thanks for this informations, very instructive.
maybe you could write a "Cnc builder's guide" Book that "do's and don'ts" the beginner in electrical, mechanical aspects.. (seriously).

"It as nothing to do with the current setting" yes, for sure ! i was talking about the current of the signal,input signal current for an AM882 is typically 10mA, minimum 7mA minimum.

> Also the Relay will be fine with 2.2KW spindle
Good news ! +1 point for the PLC4X-G2

> I think you maybe don't fully understand what the relay is used for.?

yes it is not very clear for me, the confusion certainly come from the 30A relay for the spindle on the pmdx-126 and 10A for auxilliary,
maybe it is as you said "not recommended" but they do this just in case you want to do it, or something like opening the power circuit while the watchdog isn't received.
http://www.pmdx.com/pmdx-126


Provides one 30 ampere rated electromechanical relay useful for spindle control
Provides one 10 ampere rated electromechanical relay for auxiliary functions


But if using low current is safe and is the standard practice i'll do like that.

[Boyan Silyavski]

Relays are very simple. You have signal output on your board - you could add external relay for 2$ each. You only need to have the output so it triggers the relay with 5-24v, having in mind that the LPT breakout boards have limited number of inputs and outputs and the more industrial boards could have 50 digital inputs or outputs or even 100.
Some boards have integrated a couple of relays for the coolant, spindle and so, some dont have. As i said relays are very cheap.
Thats all you will ever need to know.

[JAZZCNC]

Ok, thanks for this informations, very instructive.
maybe you could write a "Cnc builder's guide" Book that "do's and don'ts" the beginner in electrical, mechanical aspects.. (seriously).

Yes been asked that many times.!! . . . . Same answer.!! The days are not long enough now so certainly haven't got time to sit down and do this.!


yes it is not very clear for me, the confusion certainly come from the 30A relay for the spindle on the pmdx-126 and 10A for auxilliary,
maybe it is as you said "not recommended" but they do this just in case you want to do it, or something like opening the power circuit while the watchdog isn't received.
http://www.pmdx.com/pmdx-126


Provides one 30 ampere rated electromechanical relay useful for spindle control
Provides one 10 ampere rated electromechanical relay for auxiliary functions




Well your kind of right but still wrong.!!
The relays built into the PMDX and Other Bob's do show there relays controling spindle power. But these are Spindles like routers, Kress etc that use AC mains voltage directly. They don't use them or recommend using them for cutting power to Spindles controlled thru inverters.
You will damage the VFD sooner or later if you do this.

Regards the Sharing of Signal to control 2 drives then again Current won't be the issue and it will work even with the AM882. But It won't work correctly as you'll get all kinds of strange behavor mostly revolving around pulse timing and resonance issues.
Unless you like wasting time then best avoided.!!