[TomKerekes]

Hi jim_cliff11,

They should work with Kanalog.

Regards

[jim_cliff11]

Hi all,

Just wiring the lot up now and have a few questions:

1. Does Kanalog recieve it's power from the Kflop board JR1 power supply? I'm using a standard PC power supply which will put 5v and 12v in.
2. I'll be running my diff encoders to JP1. There is pins for each quadrature channel A0+, A0-, B0+, B0- etc. But where from Kanalog do I take my 5v encoder supply from? I'm guessing in terms of earthing the encoder I can just use any earthing pin on Kanalog?

Thanks,
Jim

[TomKerekes]

Hi Jim,

Does Kanalog recieve it's power from the Kflop board JR1 power supply?

Yes

I'm using a standard PC power supply which will put 5v and 12v in.

PC Power supplies are usually not a good choice as they usually have an undesirable Earth GND connection. They are also over powered and the 12V is not used.

I'll be running my diff encoders to JP1. There is pins for each quadrature channel A0+, A0-, B0+, B0- etc. But where from Kanalog do I take my 5v encoder supply from?

You might use the +5V and GND terminals on Kanalog

I'm guessing in terms of earthing the encoder I can just use any earthing pin on Kanalog?

I assume you mean DC GND. Which should usually be kept isolated from Earth Ground.

Regards

[jim_cliff11]

Thanks for the reply Tom.
Found the documentation for Kflop, in which it mentions power can be taken from a pc power supply:

This connector is a standard PC-disk drive power connector which makes it easy to drive the board with an inexpensive PC power supply.

https://dynomotion.com/Help/Schemati...ctorsKFLOP.htm

What do you recommend? I don't want to risk damaging the board.

I'll run power to my encoders from JP12 pins 33,34 and 35.

Does the Kflop / Kanalog have an enable / charge pump pin? Which can be attached to an emergency stop for example?

[TomKerekes]

Hi Jim,

What do you recommend? I don't want to risk damaging the board.

A PC power supply is not likely to damage KFLOP. However as I stated it usually has a connection to it's case and Earth Ground and is not isolated. This might cause noise problems and ground loops. It is also designed for high wattage like 350W not the 10W or less that KFLOP will consume.

Isolated 5V 10W regulated switching power supplies are commonly available from many sources at low cost. I find the Meanwell brand is reliable. Here is one at mouser for < $8
https://www.mouser.com/ProductDetail...ldxXZPuw%3d%3d

I'll run power to my encoders from JP12 pins 33,34 and 35.

That would work, but you will need GNDs also. Or use the screw terminals.

Does the Kflop / Kanalog have an enable / charge pump pin? Which can be attached to an emergency stop for example?

Yes there is a TTL signal ENABLEALL on JP12 and a relay driver output SWE. These activate after KFLOP has booted and while KFLOP is communicating with Kanalog. See:
Kanalog Hardware Info - Dynomotion

Regards

[TomKerekes]

Hi Jim,

thanks for your patience in general. It's much appreciated!

No. Thanks for your patience.

I'm guessing if the RESET button on Mach3 is triggered then the SWE will be un-grounded (disabling drives). Or if a limit switch is triggered drives are disabled.

Actually no. SWE is active so long as KFLOP is correctly communicating with Kanalog. There are Axis Enable Outputs t that can be configured in Mach3 to deactivate things when Mach3 goes into its EStop/Reset mode.

In my case I will run 24v to pin 1 (JP15 - Kanalog). Pin 2 will then run through all 'drive ready' Bb pins in series and then to 0v. This is then configured in software to STOP program when opto-input 1 is LOW.

That sounds correct.

Regards

[mach-mate]

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[jim_cliff11]

Instead of using SWE I’ll run the coil gnd to switch 7 (pin8 - JP8). But I’ll put another relay downstream effectively that’s triggered from SWE. That way the RF signal isn’t high until Kanalog has fully booted up and the axis enable switch is active in software.

Tom with regards to multiple supplies. Kflop / Kanalog is now powered from a 5v mouser supply as you suggested. My main control circuit is powered from a 24v transformer which I would use to supply the relays mentioned above. As the outputs in JP8 switch to ground through the Kanalog would I need to connect my 24v supply ground / 0v to a ground terminal on Kanalog?

Thanks

[TomKerekes]

Hi Jim,

Tom with regards to multiple supplies. Kflop / Kanalog is now powered from a 5v mouser supply as you suggested. My main control circuit is powered from a 24v transformer which I would use to supply the relays mentioned above. As the outputs in JP8 switch to ground through the Kanalog would I need to connect my 24v supply ground / 0v to a ground terminal on Kanalog?

Yes. The Kanalog Relay Drivers are not isolated. The idea is that the relays should provide isolation. If you use the same power supply as used with the opto isolated circuitry you will defeat the isolation. So you really should use separate supplies.

By transformer I assume you mean DC power supply? The Relay Drivers only work with DC.

Note you should place a reverse diode right across any relay coil to limit the reverse voltage spike that occurs when a coil is switched off.

HTH
Regards

[jim_cliff11]

Hi Tom,

The machine has 2 x 240vac, 1 x 110vac and 1 x 24vac transformer. I know that the original PLC ran off 110vac and 24vdc. The majority of outputs, relays etc are either 110vac or 24vdc as I tested them when the old system was running. The only issue I have now I'm not receiving 24vdc through any of the corresponding feeds, but I am getting 24vac from the transformer. There must be a rogue rectifier hiding somewhere!!

I've just bought two 24vdc 10amp supplies so I might just wiring these in to be honest. I'll run the GND from just one of these supplies to a ground screw terminal on Kanalog. Then the second supply I'll isolate and use on opti-outputs.

Are there any functions which you'd recommend run through the opto-isolated outputs rather than the relays? Or it completely up to application and customer.

Thanks,
Jim

[TomKerekes]

Are there any functions which you'd recommend run through the opto-isolated outputs rather than the relays? Or it completely up to application and customer.

Yes it mostly depends on your system. Typical things are Spindle ON/OFF, CW/CCW, and Drive Enables.

Regards

[jim_cliff11]

Thanks Tom, nearly ready for the first firing up to test the security circuit.

Before I connect the DACs I’ve just has a thought.....

Kanalog’ DACs share a common gnd, with only 1 analog +-10v signal per drive essentially. When I tested my drives I basically put 10vdc in one drive input pin and gnd to the other pin to achieve movement in one direction. Then swapped the gnd and 10vdc inputs pins round to achieve movement in the other direction. There isn’t a set gnd pin or input pin on the drives. They work in pairs swapping polarity so it seems. In the drive manual it describes these two input pins as differential and as such resistors are in place / removes to accommodate this input type.

How will this work with Kanalog putting +-10vdc into just one pin with the other permantly connected to Kanalog gnd? I’m confused :S

Surely it can’t work?

[jim_cliff11]

Hi Tom, yet again thanks for your reply. Your help has been invaluable!

I've cracked on well today. All 3 axis (X,Z and spindle) are now configured in the config / flash screen after loading KanalogInitialPID.mot and setting subsequent channels. I then went on to start tuning via the step response screen with the following results:

Chan1 - Increased the P-Gain, adjusted velocity, acceleration and jerk.

Servo motor sounded like it was vibrating unhealthily. Also what would cause the resulting dither in the green command output plot? Surely this isn't good?

Chan 1 - Having dropped the P-Gain down slightly I got the following plot:

Which looked and sounded much better.

Any thoughts Tom? Both the X axis (chan1) and Y axis (chan2) are now set identically in terms of step response. Both give very similar plots. When enabled and zero'd both fluctuate by 2-3 encoder codes which is good enough for me!


Not as much luck with the spindle.
When zero'd using standard settings (0.2p gain) the spindle juddered backwards / forwards violently.
http://81.138.85.180/~jim_cliff11/20...O-00000028.mp4

And gave me the following step response plot:

I increased the gain to 1 very briefly, but the intensity and speed of the judder motion was concerning.

Dropping the P gain down to 0.05 reduced the intensity of the judder to a safe level
http://81.138.85.180/~jim_cliff11/20...O-00000029.mp4

And gave me the following poor results:


I found a page on Dynomotion referring to the setup of an open loop DAC axis to control spindle. I'm guessing if I configured the spindle this way without encoder feedback I wouldn't have the judder issue. Realistically this isn't a viable option as it's essential I have encoder feedback on the spindle for threading (the majority of my work). What would be the best way of producing a healthy step response plot (if its even needed for spindle control), eliminating the judder, yet maintaining closed loop encoder feedback?

Thanks once again

[TomKerekes]

Hi jim_cliff11,

Before I connect the DACs I’ve just has a thought.....

Kanalog’ DACs share a common gnd, with only 1 analog +-10v signal per drive essentially. When I tested my drives I basically put 10vdc in one drive input pin and gnd to the other pin to achieve movement in one direction. Then swapped the gnd and 10vdc inputs pins round to achieve movement in the other direction. There isn’t a set gnd pin or input pin on the drives. They work in pairs swapping polarity so it seems. In the drive manual it describes these two input pins as differential and as such resistors are in place / removes to accommodate this input type.

How will this work with Kanalog putting +-10vdc into just one pin with the other permantly connected to Kanalog gnd? I’m confused :S

Surely it can’t work?

Unlike your fixed +10VDC source a Kanalog DAC output can be +10VDC or -10VDC or anything in between. So there is no need to swap the direction to change the polarity.

HTH
Regards

[jim_cliff11]

Thanks for the clarification Tom.

So it turns out the Bb relay outputs on the drives are closed when the drives receive mains power, even if the rf signal is not present. Therefore I’ve got no drive stop feedback to Kanalog.

Tom would the revised attached circuit work? Can I set opto input 1 to disable program when it recieves low AFTER sw6 is active? So when SW6 goes high (to enable drives) if opto in 1 after this point recieves a low signal then it disables the program, such as the estop will do? I appreciate this will contradict the opto-isolation, but i may use an alternative input. Just for example sake on any input would this work?

Or will sw6 not go High initially because opto in 1 will be in a low state?

The alternative is I put the limit switches on a separate circuit into their own input to disable drives when low? And not have them in the rf line.

Thanks,
Jim

[jim_cliff11]

Thanks Tom,

The link you posted to the Dynomotion wiki page explains the tuning process in depth! I'm surprised I missed that article. Either way, it makes a lot of sense, so I'll have another go on Monday. Some of the values shown on that page for velocity, acceleration and jerk are much higher than the values I used in the screenshots. I'll increase the step size to give the servo's more room to push for optimum values.

In terms of P-gain, what is the maximum value that can be used? I know the higher the value the lower the following error, but this also leads to drive instability. When I'm putting in a max P of 1.5 and hearing the servo vibrate or sound unhealthy, I then drop it right down out of fear of damaging something. I've seen on some threads people using Kanalog have tried gains of 5+.

Taking all the above into account I guess I'm just worried about damaging a drive or servo. Is there a risk of this or would the drive just trip?

Moving on to the spindle for example, if I increase P-gain to say 3, would I be right in thinking dither / judder amplitude would reduce but frequency increase? Potentially this movement would then be unnoticeable. But is there any risk of damaging the drive changing these values?

Like you say I could avoid the judder by disabling the spindle axis, but then I get drift which causes the axis to spin slowly until it's enabled. Neither are ideal. I'd rather have the judder unnoticeable when spindle enabled, without risk to the drive.

Thanks

[TomKerekes]

Hi Jim,

You will write a small C Program to handle all of this so you are able to handle things however you wish. You can turn SW6 on or off whenever you wish. And you can monitor Opto In1 or Opto In2 however you wish and based on its state disable whatever you want.

Possibly you might turn on SW6 as the system is being initialized. Afterward you might monitor Opto In 1 and if it ever goes low disable the KFLOP Axes and turn off W6.

HTH
Regards

[jim_cliff11]

Hi Jim,

You will write a small C Program to handle all of this so you are able to handle things however you wish. You can turn SW6 on or off whenever you wish. And you can monitor Opto In1 or Opto In2 however you wish and based on its state disable whatever you want.

Possibly you might turn on SW6 as the system is being initialized. Afterward you might monitor Opto In 1 and if it ever goes low disable the KFLOP Axes and turn off W6.

HTH
Regards

Thanks Tom,

I’m away skiing at the moment but when I get back I’ll crack on and get it going.

[jim_cliff11]

Ok, the wiring is all done for limits, relays, axis brakes, power supply and drive requirements.
I will post a complete schematic up when I confirm it all works.
Quick question though Tom:

Using the opto-inputs on Kanalog, see the circuit below:

The SPDT switch is to over-ride the limits when needed.



If I test continuity between the +ve & -ve of the 24v supply the multimeter beeps (minimal resistance as we'd expect). There's not actually any load present on the circuit. Surely in practice this would effectively short out the supply and blow a fuse (like putting a jumper wire from + to -)? This may seem like a dumb question, but its been puzzling me the last week or so.

Thanks

[jim_cliff11]

The Z axis is the only one I've had good results with so far today. I've reduced velocity by 30% of max and have found a good acceleration and jerk value. The servo responds well, sits at commanded 0 with little fluctuation in encoder counts and hums nicely. All sounds smooth.

http://81.138.85.180/~jim_cliff11/080418/Z.mp4




X on the other hand. The command and actual values come out well with P = 6. But the servo sounds horrendous. Vibrating rapidly when at commanded 0 (enabled), I can actually feel the vibrations through the machine. The only way to eliminate this vibration and have a smooth sounding servo is reducing the P to 1. But then I'm using 200DAC counts and have poor command and position plots. In the video below, right at the end when I disable the axis you can grasp just how bad the vibration had been.

http://81.138.85.180/~jim_cliff11/080418/X.mp4




The Spindle is just a nightmare. Smoke was coming from the motor or the belt before, so the whole thing isn't doing it good. You were right Tom, increasing the gain has no effect. The spindle "judder" is now more like a yoyo at commanded 0. Amplitude starts off high with a low frequency, then each time it switches direction the amplitude gets higher, the frequency lower. Sort of a like a reverse pendulum effect. When the drive is disabled, it slowly rotates. When it is enabled @ commanded 0 that's when I get the judder. See below:

http://81.138.85.180/~jim_cliff11/080418/Spindle1.mp4



I feel like I'm wrong in treating the spindle like the Z or X axis, wrong when trying to get similar results and wrong with the encoder input somehow. It doesn't have to be accurate like the actual axis, just give me an RPM reading and provide basic feedback for threading. The required function of the spindle is completely different from that of the axis. And as such, I don't know what results to expect in the step response when setting a spindle up with encoder feedback. What should a good step response plot look like for a closed loop spindle? Also would it be worth changing the input channel to read just the Z pulse (1 pulse per rev)? And not the A and B channels?

Had enough today, the spindle is annoying me and I cant loose the X vibration. Can you make any sense of all this Tom?

Thanks