Dynomotion

Group: DynoMotion Message: 10905 From: timbosaurus Date: 1/24/2015
Subject: Connection strategy for Kflop+kanalog to 3-axis servo mill

HI all,


After some great suggestions on how to better configure my little laser, I thought I'd try my luck on any suggestions on the plan for my mill.


It's a large, servo driven, 3 axis machine, with brushed DC motors, differential encoder feedback, +/- limit switches on each axis, and a few user input controls.  


For the driver outputs, I plan to use:


X-axis analog +/-10V out and GND - DAC0, JP11 Pin1 and 9

Y-axis analog +/-10V out and GND - DAC1, JP11 Pin2 and 10

Z-axis analog +/-10V out and GND - DAC2, JP11 Pin3 and 11


For the axis encoder inputs, I plan to use:

X-axis encoder (8 wire: A, /A, B /B, Z, /Z, +5V, 0) - Differential input 0, JP1 A0+, A0-, B0+, B0- (No Z index connection yet), 
Y-axis encoder (8 wire: A, /A, B /B, Z, /Z, +5V, 0) - Differential input 1, JP1 A1+, A1-, B1+, B1- (No Z index connection yet)
Z-axis encoder (8 wire: A, /A, B /B, Z, /Z, +5V, 0) - Differential input 2, JP1 A2+, A2-, B2+, B2- (No Z index connection yet)

Q - I will take +5V from JP8 pin 14, but which connector on the Kanalog would you suggest I take gnd from for these encoders?  
Q - I assume it is OK not to use the Z index pulses, unless I wanted them for more accurate homing?

For the limit switches, I plan to use:


X-axis pos limit switch - Opto Input 0, JP15 Pin 1&2

X-axis neg limit switch - Opto Input 1, JP15 Pin 3&4

Y-axis pos limit switch - Opto Input 2, JP15 Pin 5&6

Y-axis neg limit switch - Opto Input 3, JP15 Pin 7&8

Z-axis pos limit switch - Opto Input 4, JP15 Pin 9&10

Z-axis neg limit switch - Opto Input 5, JP15 Pin 11&12


For moving the table around, there are 3 'handy wheels', that are simply 4-wire single-ended encoder wheels. So I was going to bypass the Kanalog differential inputs and connect these straight to the Kflop. For the handy wheels, I plan to use:

X-Axis handy wheel (4 wire: +5V, GND, A, B) - Connect A&B to Kflop Encoder 5 input , Kflop JP5 pin 3&4
Y-Axis handy wheel (4 wire: +5V, GND, A, B) - Connect A&B to Kflop Encoder 6 input, Kflop JP5 pin 5&6
Z-Axis handy wheel (4 wire: +5V, GND, A, B) - Connect A&B to Kflop Encoder 7 input ,Kflop JP5 pin 7&8

Q - Once again I will take +5V from JP8 pin 14, but which connector on the Kanalog would you suggest I take gnd from for these encoders?  

I also have a momentary switch on the machine to power on/enable drives.  Basically the drives stay completely dead after the mill is powered, until this switch is pressed.

The intention is to write a thread on kflop that starts on power up and wait for this 'enable' switch.   After the enable switch is triggered, kflop will perform it initialisation of I/O (handy wheels, coolant switches, etc), enable the drives and start to servo, even if not connected to Kmotion or KmotionCNC.    I want it this way so I can use the mill manually even if the PC is broken/missing/slow to bootup/etc.  Does this sound like a reasonable plan?

Any suggestion on simplifying the connection strategy, particularly around the two types of encoders that I need to hookup, are most appreciatied.

Cheers,
Tim

 
Group: DynoMotion Message: 10906 From: Tom Kerekes Date: 1/24/2015
Subject: Re: Connection strategy for Kflop+kanalog to 3-axis servo mill
Hi Tim,

That all sounds very reasonable to me.

For the differential encoders any GND on Kanalog should work such as those on Kanalog JP6

Z Index pulses are not required if you don't wish to use them.

For the Single Ended MPG encoder connections to KFLOP it may be better to connect to a KFLOP GND such as any of the connectors (JP4, JP6, JP7) or the GND lug.

Good luck.
Regards
TK

Group: DynoMotion Message: 10907 From: az@AIMELE.COM Date: 1/24/2015
Subject: Re: Connection strategy for Kflop+kanalog to 3-axis servo mill
I like your idea of having the Kflop run a thread on power up to manually move the machine if the PC is AWOL.  However,  I thought the K flop was "blank" on power up and the PC was needed to download the threads on every power up unless you Flashed it...  which is not recommended.  Am I missing something?

AZ



Group: DynoMotion Message: 10908 From: Tom Kerekes Date: 1/24/2015
Subject: Re: Connection strategy for Kflop+kanalog to 3-axis servo mill
Hi Tim/AZ,

I missed that part about Flashing a power up program to KFLOP.  As AZ points out you would need to do that in order to have that functionality without a PC.

The only reason we don't recommend Flashing User Programs is because in most cases (unlike this) it is unnecessary and it can be confusing.   You will need to keep track of what is Flashed into KFLOP.  If you swap KFLOP to another location you will need to remove or change what is Flashed into the board.  To upgrade to a newer Version you will need to Upgrade to the new Version and then re-Flash your startup program.  If you are careful, know what you are doing, and keep track of what you have done, there is no issue.

HTH
Regards
TK

Group: DynoMotion Message: 10912 From: timbosaurus Date: 1/24/2015
Subject: Re: Connection strategy for Kflop+kanalog to 3-axis servo mill
Ah, OK. Thanks Guys!

I thought the "launch on power up setting" allowed standalone operation, but I am often wrong  :)  Is it that this setting still needs the PC present to compile/download the thread before executing, or does this setting allow true standalone, but as Tom mentions, does need to be used carefully?

I have some digital IO to connect:
  • 6 limit switch inputs (X, Y, Z)
  • 6 +/- jog/rapid joystick inputs (X, Y, Z)
  • 3 handywheel resolution inputs (x1, x10, x100)
  • 1 power on/enable input
  • 1 coolant toggle


So I plan to use the kanalog opto inputs on the most important signals with 24V (eg: limit switches and power on/enable), and then connect the rest between kanalog 3.3Vout and kanalog 3.3V LVTTL inputs.  

But because I need more 3.3v inputs than the 8 provided on kanalog, is it OK to run 8 into the kanalog JP12 (#128-135) and the rest into kflop Aux#0 (#16-23)?  The 3.3V supply on kanalog and kflop is the same, right?

Thanks,
Tim
Group: DynoMotion Message: 10918 From: Tom Kerekes Date: 1/25/2015
Subject: Re: Connection strategy for Kflop+kanalog to 3-axis servo mill
Hi Tim,

The Flash User Data and Launch on power up settings do allow stand alone operation without a PC.  You must use a PC to Compile/Download the programs to KFLOP before Flashing User Data Memory, but after doing so a PC is not required to execute the programs on Power Up.  But we ask that you use it only as required and carefully.

Yes you can use both Kanalog 3.3V LVTTL inputs and KFLOP's 3.3V LVTTL inputs.  However it sounds like you don't understand how to drive LVTTL signals.  They are voltage sensitive inputs that must be driven both high (ie more than 2.8V) and low (less than 0.4V).  A simple switch to 3.3V will drive the signal high when closed, but will not drive it low when it opens.   A solution can be to add something like a 1K ohm pull down resistor (from the IO pin to GND) to drive the pin low when the switch opens.  The first 8 I/O on both KFLOP JP4 and JP6 have 150 ohm pull down resistors.  So those 16 I/O would work with a simple switch to 3.3V.

Yes the 3.3V supply on Kanalog is the same as on KFLOP.

Note 3.3V signals are somewhat noise sensitive so you should follow normal practices to keep wiring short, away from switching power and motor wiring, and ideally shielded on the KFLOP side to KFLOP GND.

HTH
Regards
TK

Group: DynoMotion Message: 10931 From: timbosaurus Date: 1/26/2015
Subject: Re: Connection strategy for Kflop+kanalog to 3-axis servo mill
Thanks Tom,  

I was just trying to find a good solution to allow me to add more 24V I/O to the Kanalog and avoid using LVTTL for switch, when I saw you're Konnect board.  Woohoo!

It sounds perfect, so I'll order one along with a second Kflop so I dont have to keep on swapping the one that I do have between the router and the mill.

Is there any chance that the mounting holes of the Konnect line up with those on the Kanalog (obviously on the opposite side to Kflop)?

Because I don't mind mounting the Kanalog off to the side, but this would need an 8" ribbon cable to separate it with enough room for the wiring, but if it mounted above the Kanalog beside the Kflop, then the cable would only be about 3".

Cheers,
Tim