[Charles2]

See plots and data.

[TomKerekes]

Hi Charles,

One possible source of confusion might be the how the Coordinate Motion System is defined. I believe you had:

DefineCoordSystem(0,1,2,-1);

The Spindle should not be included in the Coordinate System if operated as a Spindle. And this defines X=axis 0, Y=axis 1, Z=axis 2. So when Jogging the Z axis the Spindle is being commanded. And when any Jogging is stopped all axes are stopped. I think it should be:

DefineCoordSystem(0,-1,1,-1);

To define X=axis 0, Z=axis 1 and no others.

I don't think that explains everything though.

Move2=0 took spindle to the second mark from yesterday. After jogging axis, would sometimes go to mark and sometimes not.

This of course should never happen, No matter how jerky or erratic the Spindle motion is the encoder should track the position without loosing count. The only thing that should change it is a reset of the Encoder Position or a re-boot. So you might investigate what causes this. If it ever looses count something is wrong.

The black wires in the encoder cable are shielded/twisted pairs as grouped above. The black pair connected to 0V are combined and the red/white pair are combined. The others are not combined. The other black wires are the positive compliment to the paired colored wire and are connected to A2+, B2+

This is correct on the Kanalog end. But the question is whether they are connected to the correct signals from the encoder.

Tried to test voltage on the encoder wires to ground, but even at .5 RPM, my voltmeter may not be fast enough to keep up. Showed about .8 - 2.8 volts.

You could disable the Spindle Amp or unplug it so it has no power and should then sit still. You can then check A+ A- B+ B- are all at valid levels and complementary. Then rotate some random amount until all 4 possible states are checked.


The Plot 128 shows some small DAC shift and interaction. The axis also seems to be on the verge of instability. I thought I saw earlier plots with D=15 and much more stable. But the instability doesn't explain the shift. Before the Jog the DAC is about -14 to hold position. After the Jog the DAC is about -24 to hold position. Its not clear when you stopped the Jog and if the offset persisted or only exists while Jogging. A 10 DAC counts shift is 10 / 2047 x 10V = 49mV. I suppose it could be a defective Kanalog. You might try using DAC 4 for the spindle as a test.


I think you have those deadband Programs writing to the DACs? Do you? Maybe those have a bug. Please post them. You might eliminate those to see if that's the cause of the interaction.

Sorry for no simple answers.

[Charles2]

I changed the coordinate system definition as suggested.

In the same C program, Init3Analog02, should the spindle axis be enabled along with the X and Z?

As I said before, I checked the pinout at the encoder plug. It does not match the prints that I have. When I switched the wires at Kanalog to match the prints, the spindle ran away. I don't have a wiring diagram for the encoder.

I still need to check the output from the encoder.

I don't have the deadband program running right now.

New observation today:
Power up machine. Enable ch2 (spindle) on Step Response screen. Go to KMotionCNC screen. Before hitting INIT button, Z- slow button jogs spindle CCW with direct control (jogs spindle when button is pushed, stops when let off). Z+ slow button jogs CW with direct control. Axis does not move. X buttons do nothing. Spindle starts and stops with on and off buttons. Hitting INIT button will allow X and Z to move as expected. Spindle shutters.

Thanks

[Charles2]

New problem. Started KMotion this morning. Looked normal. Started KMotionCNC. Message block reads "Unable to open Tool Table File". "C:\KMotion435f\KMotion\Data\" Hit ok. Cnc screen is not the way I left it. Looks like default screen. I use lathe screen. Went to Tool Setup screen. Everything is gone. Selected 'Basic Lathe 2 Axis'. Same message again. It went to lathe screen, but nothing works. No INIT button. All user buttons are blank. Trajectory Planner is at default. When I exit KMotionCNC, the message "Configuration File was not properly loaded on startup. Would you like to save the current configuration?" I hit 'No'. What have I done?

Anyway, I switched the spindle encoder command wire from dac2 to dac4. Spindle will run on Dac4 commands. Spindle is still affected by step response moves or Console commands, same as before.

Please explain proper way of checking encoder with multimeter. Do I check across A-,A+ then B-,B+ or each wire to gnd? I assume the wires are to be disconnected from Kanalog. All this while turning and stopping the encoder, while powered up, with spindle drive fuses out.

Thanks

[TomKerekes]

Hi Mark,

In the same C program, Init3Analog02, should the spindle axis be enabled along with the X and Z?

That depends on whether you want the Spindle to be trying to hold position while not in use or disabled. If it is disabled then the Spindle programs will need to also enable/disable it rather than just Jogging the axis assuming that it is already enabled.

New observation today:
Power up machine. Enable ch2 (spindle) on Step Response screen. Go to KMotionCNC screen. Before hitting INIT button, Z- slow button jogs spindle CCW with direct control (jogs spindle when button is pushed, stops when let off). Z+ slow button jogs CW with direct control. Axis does not move. X buttons do nothing. Spindle starts and stops with on and off buttons. Hitting INIT button will allow X and Z to move as expected.

Well don't do that And it makes perfect sense. You shouldn't enable an axis until things are configured. By default Axis #2 is the Z axis.

I assume you pushed the "Enable" button on the Step Response Screen? That configures the Axis to the Screen settings before enabling.

New problem. Started KMotion this morning. Looked normal. Started KMotionCNC. Message block reads "Unable to open Tool Table File". "C:\KMotion435f\KMotion\Data\" Hit ok. Cnc screen is not the way I left it. Looks like default screen. I use lathe screen. Went to Tool Setup screen. Everything is gone. Selected 'Basic Lathe 2 Axis'. Same message again. It went to lathe screen, but nothing works. No INIT button. All user buttons are blank. Trajectory Planner is at default. When I exit KMotionCNC, the message "Configuration File was not properly loaded on startup. Would you like to save the current configuration?" I hit 'No'. What have I done?

That would indicate the disk file that holds the Configuration was corrupted. \KMotion\Data\GCodeConfigCNC.txt That can sometimes happen if the PC is powered off without doing a proper shutdown. What Version are you running? Newer Versions keep a backup copy as GCodeConfigCNC.txt.bak that is automatically used if the primary is corrupted. If you have a backup of the Data directory you could restore that file.

Anyway, I switched the spindle encoder command wire from dac2 to dac4. Spindle will run on Dac4 commands. Spindle is still affected by step response moves or Console commands, same as before.

ok good to know

Please explain proper way of checking encoder with multimeter. Do I check across A-,A+ then B-,B+ or each wire to gnd? I assume the wires are to be disconnected from Kanalog. All this while turning and stopping the encoder, while powered up, with spindle drive fuses out.

Actually it would be better to leave connected to Kanalog. Check each signal relative to GND. + and - should always be opposites (one high and one low). Note with a high resolution encoder even when stopped there might be some drift so you should take that into consideration. That is if for example one is high and the other is high then there might have been 1 count of movement since measuring the first. So go back and re-measure the first to see if that was the case.

[Charles2]

Hi Tom,

I reloaded KMotion435f and restored the Tool Setup pages. Back to my normal.

Checked spindle encoder signals as instructed. A+ wire switches from 128mV to 3.30V, A- switches from 3.54V to 123 mV, B+ switches from 3.30V to 128mV, B- switches from 123 mV to 3.54V. Values are low, high, high, low, complimentary.

I am using channel 2 for spindle. Would it be better to use channel 4 or something else? The INIT C program is the Init3Analog example, so ch2 is populated for the spindle. Could this be causing some kind of confusion in KFLOP or something? If I need to change to 4 or something, does the "Export All to Open C Program" button take care of the INIT file, or do I need to do something else to replace ch2 with ch4 in INIT?

Thanks

[TomKerekes]

Hi Mark,

Checked spindle encoder signals as instructed. A+ wire switches from 128mV to 3.30V, A- switches from 3.54V to 123 mV, B+ switches from 3.30V to 128mV, B- switches from 123 mV to 3.54V. Values are low, high, high, low, complimentary.

The levels are all valid high and low. But what is is important to check is if + is high the - should be low and vice versa. Its not clear if you checked this.

I am using channel 2 for spindle. Would it be better to use channel 4 or something else? The INIT C program is the Init3Analog example, so ch2 is populated for the spindle. Could this be causing some kind of confusion in KFLOP or something?

No it shouldn't matter if you configure and enable in the proper sequence.

If I need to change to 4 or something, does the "Export All to Open C Program" button take care of the INIT file, or do I need to do something else to replace ch2 with ch4 in INIT?

If you have the INIT file as the open c Progran and "Export" it should update it properly.

[Charles2]

When A+ was high, A- was low and when A+ was low, A- was high. When B+ was high, B- was low and when B+ was low, B- was high.

Any thoughts on what else could be causing this interference between the spindle and X,Z Axis'?

[TomKerekes]

Hi Charles,

So it seems the encoder is wired correctly. Although you caught it failing intermittently before. Did you ever go back to see if the Spindle zero position shifts unexpectedly again?

Did you re-tune the Spindle so it isn't marginally stable?

You might re-Flash New Version to make absolutely sure nothing odd has been inadvertently changed in KFLOP.

I suppose we could send a replacement Kanalog to see if there is something damaged on Kanalog.

If possible you might test the Kanalog DACs with a Voltmeter. Command various voltages to DACs with Drives disabled and check with a voltmeter. That the Voltages change appropriately and changing one DAC has near zero effect on others. The intersection might be in the 50mV range. I'd first leave the DACs connected to the Drives so they are loaded normally.

You might also check that the +/-15V analog supply is correct on Kanalog JP12 Pins 25 and 27. They should remain within +/-5% of 15V and -15V. Take care not to short anything.

[Charles2]

Hi Tom,

How is spindle zero position determined by KFLOP? I am don't remember assigning the spindle encoder marker anywhere. Thought that would come later. Will check Kanalog as you suggested.

Thanks

[TomKerekes]

Hi Charles,

How is spindle zero position determined by KFLOP? I am don't remember assigning the spindle encoder marker anywhere. Thought that would come later.

The Z marker position is not normally needed. When you power up Kanalog or Zero the Spindle Encoder wherever the Spindle is will be zero.

[Charles2]

Hi Tom,

I ran the Kanalog tests last night, then spent some time writing it up to post. Seems it didn't submit. So I am rewriting. If it shows up twice you'll know why.

I need to tune the spindle better. The spindle position failures may have been due to cycling power. Will retest without cycling power.

If you would send a Kanalog replacement and it solves the spindle problem, I would be happy to return my Kanalog for evaluation. If it turns out that I have damaged it, I will gladly pay for the replacement.

I tested the Kanalog DACs 0 thru 7 as suggested. I commanded 0, 100, 500, 1000, 1500, and 2000 DAC counts on each DAC. I first left X, Z, and the spindle wires connected, but since I have limited axis travel, the X and Z wires were disconnected while testing DACs 0 and 1.
At DAC=0, all terminals checked between -40mV and +24mV. As each DAC was checked at 100 counts, the voltage measurements were from -453mV to -519mV, with those not commanded staying very close to the 0 count command, or basically unaffected.

500 counts yielded from -2.40V to -2.45V, with those not commanded unaffected.

1000 counts yielded from -4.81V to -4.88V, with DACs not commanded unaffected.

1500 counts yielded from -7.21V to -7.30V, with DACs not commanded unaffected.

2000 counts yielded from -9.62V to -9.72V, with DACs not commanded unaffected.

While X and Z command wires were disconnected from DAC output terminals, started KMotionCNC, hit INIT, attempted to jog X and Z axis. Spindle was unaffected.

Powered off control. Reconnected X and Z wires. Powered back on. Started KMotionCNC. Hit INIT. Spindle then jerked when jogging X and Z.

Checked pins 25 and 27 on JP12. Pin 25 checked +14.99V and pin 27 checked -14.98V.

Re-Flashed New Version. Spindle still jerks when jogging X and Z.

Hope this is not too confusing.

Thanks

[TomKerekes]

Hi Charles,

Thanks for the detailed info clearly explained. Strange I see no reason for the interaction.

I need to tune the spindle better. The spindle position failures may have been due to cycling power. Will retest without cycling power.

Very possibly. Make sure you have some Spindle Jerking to check if that causes a loss of counts.


The measurements are all as expected with no issues. Servo DACs don't need to be highly accurate, only consistent, linear, and without cross talk, Kanalog uses 1% Tolerance components.

I first left X, Z, and the spindle wires connected, but since I have limited axis travel, the X and Z wires were disconnected while testing DACs 0 and 1.

Well I would have left X and Z connected but instead removed X Z motor power. That way the DAC Outputs would still be loaded by the drives. If the drives are overloading the DAC Outputs, or some leakage between wiring or the Drives then we wouldn't observe it. I know it is unlikely but it has to be something. If we could observe something wrong it should be straightforward to track down the cause.

Actually what matters is the DAC Voltage right across the Spindle Drive's + and - Reference input. Is it difficult to measure there? So we might disable the Spindle Axis and command some small DAC Voltage to the Spindle. Then Measure the Reference voltage. Then Jog X Z to see if the voltage changes. Also observe if the Spindle changes speed or Jerks.

[Charles2]

Hi Tom,

Retested DACs 0 and 1 with wires connected at Kanalog and motor wires disconnected at X and Z drives. Voltages recorded at DACs were within .02V of tests with DAC wires disconnected. No cross talk.

Connected voltmeter to spindle drive high and low inputs. Commanded DAC4=100. Voltage at drive input checked -454mV, same as at Kanalog.

Jogged Z- from KMotionCNC. Drive input voltage went from -454mV to -528mV, then back to -454mV when jogging stopped.

Jogged Z+, voltage -531mV.
Similar results from X.
Spindle sped up slightly, no jerking.

DAC4=0 left spindle idling, voltage at spindle drive inputs was 21mV. Spindle was turning CCW. Jogged Z axis. Voltage went to -49mV and spindle switched to CW.

Note: When I checked all the DACs at Kanalog, with no command at DAC4, it consistently checked about 24mV.

- - - Updated - - -

Hi Tom,

Retested DACs 0 and 1 with wires connected at Kanalog and motor wires disconnected at X and Z drives. Voltages recorded at DACs were within .02V of tests with DAC wires disconnected. No cross talk.

Connected voltmeter to spindle drive high and low inputs. Commanded DAC4=100. Voltage at drive input checked -454mV, same as at Kanalog.

Jogged Z- from KMotionCNC. Drive input voltage went from -454mV to -528mV, then back to -454mV when jogging stopped.

Jogged Z+, voltage -531mV.
Similar results from X.
Spindle sped up slightly, no jerking.

DAC4=0 left spindle idling, voltage at spindle drive inputs was 21mV. Spindle was turning CCW. Jogged Z axis. Voltage went to -49mV and spindle switched to CW.

Note: When I checked all the DACs at Kanalog, with no command at DAC4, it consistently checked about 24mV.

[TomKerekes]

Hi Charles,

Jogged Z- from KMotionCNC. Drive input voltage went from -454mV to -528mV, then back to -454mV when jogging stopped.

Jogged Z+, voltage -531mV.
Similar results from X.
Spindle sped up slightly, no jerking.

DAC4=0 left spindle idling, voltage at spindle drive inputs was 21mV. Spindle was turning CCW. Jogged Z axis. Voltage went to -49mV and spindle switched to CW.

Note: When I checked all the DACs at Kanalog, with no command at DAC4, it consistently checked about 24mV.

ok it seems we finally found something wrong.

The voltage at Kanalog and at the Drive should be the same, not 70mV different. The voltage at both ends of a wire should be the same.

There are two common causes for such a thing shown below. Missing a GND connection A. Or Ground Loop Currents B.

In case A the system is still somewhat working because of a roundabout connection through GNDs and such that shift when currents change.

In case B high motor currents are finding an unexpected path through the wire going to the Kanalog GND. With significant current through the wire there may be 70mv voltage across the resistance of the wire. You might read this.

Its hard to help without knowing the details and topology of all the wiring and GNDs in your system.

One thing to consider is to add a USB isolator for KFLOP. Usually a PC DC GND has a connection to Earth GND. Since USB is normally Common GND, KFLOP then has an Earth GND connection. Adding a USB Isolator can avoid some ground loops.

What I sometimes do is identify how all the grounds are tied together and where. With power off I then disconnect the connection and verify with an Ohm meter they are not connected. If there is still a connection then I know there is an unexpected connection through the chassis or something. Then I can remove things until I find it.

One thing that doesn't make sense is that the earlier battery test should have shown the problem. Maybe it did but it was small relative to the 1.5Volts. Another test similar to commanding the DAC4 to 0 would be to remove the wire form DAC4 and connect it directly to Kanalog GND. In this case we know the Spindle should be commanded exactly 0V. If you see 70mv at the Spindle then you know there is an issue with the wiring/grounding.

On a side note the 70mV offset may not be a DC voltage. It might be a bigger AC/Noise signal that has an average of 70mV. It would be interesting to look at it with an oscilloscope. Or another trick is to put the meter on AC. If it is a constant 70mv then it should read zero. But otherwise you can get an idea of the AC/Noise level.

HTH


Attachment 461282

[Charles2]

Hi Tom,

I must not have been clear. The 70mV difference was when jogging X and Z, read at the drive and at Kanalog Dac. The voltage at the spindle drive matches the voltage at Kanalog DAC.

With Dac4=0, voltage at drive= 23mV. At Kanalog Dac= 23mV.

With Dac4=100, voltage at drive= -455mV. At Kanalog -455mV.

Disconnected wire from Kanalog, Dac4=-455mV, wire=-5.2mV, drive=-5.2mV.

Connected spindle command wire to Dac3.
Voltage at drive=-8mV. At Kanalog=-8mV.
Dac3=100. Voltage at drive and Kanalog=-494mV.
Jog Z, voltage=-560mV at drive and Kanalog.

Connected spindle wire to Dac6.
Dac6=0. Voltage at drive and Kanalog=-5mV
Dac6=100. Voltage at drive and Kanalog=-502mV.
Jog Z. Voltage at drive and Kanalog=-555mV.

Disconnected wire from DAC, connected to Kanalog ground. Voltage at drive=0.0.
Spindle idling CCW at 13RPM. Jog Z, spindle slows to 8RPM.

[TomKerekes]

Hi Charles,

Oops I misunderstood.

Next theory In order for a Kanalog DAC voltage to change either it is being way overloaded or a current is being introduced from somewhere or it is somehow damaged. Normally a Drive input should be very high impedance (>20K Ohms) and not back feed any current. So if the drive is an excessive load or inducing significant currents that would cause the DAC output to change.

Kanalog's output amplifiers should be able to maintain its commanded voltage while sinking/sourcing 10ma of current. If you have any resistors you might test Kanalog's output amplifiers. I tested with a 1 KOhm resistor. I commanded DAC3=200 and unloaded measured -0.983V. I commanded DAC0=-2047 to be approximately +10V. I then connected the 1KOhm between the DACs. With an 11V difference across the resistor 11ma of current should flow. DAC 3 was pulled upward to -0.977 a change of 6mV. We are seeing a shift on your system of an order of magnitude more than this.

So if you could possibly perform this test on your Kanalog we could determine if it is working properly.

Next if your multimeter has a milliamp current measurement mode, we might repeat the test where the Spindle Drive Input is connected to Kanalog GND at the Kanalog end. But instead of connecting it to Kanalog GND directly connect it through the multimeter. This will tell us how much current is required to hold the signal at 0V. Then Jog XZ and see if the current changes.

[Charles2]

Hi Tom,

Thinking about interference possibilities, I rerouted the spindle tach cable outside of the cabinet. No change. Spindle still reacts to axis movements.

Disconnected spindle encoder shield at Kanalog, in case it may be connected at the encoder. No change.

Disconnected X and Z encoder shield at Kanalog for same reason. No change.

Rerouted spindle encoder cable outside of the cabinet. No change.

Dac6=200, unloaded, checked -.985V.
Dac1=-2047, unloaded, checked 9.88V.
Connected 1 Kohm resistor between DAC1 and Dac6. Dac6 was pulled upward to -.980 or 5mV change.

Connected multimeter set to DC amps between Kanalog ground and spindle drive input. Meter reading was .001. Jogged X and Z, reading did not change. Slight reaction at spindle- still or rotating CCW at 0.1-0.8 RPM. Axis jog direction positive or negative causes CW rotation at 1.5-1.8 RPM.

Connected spindle drive input straight to Kanalog ground. Rotation CCW, slowly increasing to 14.2 RPM. X or Z jogging results in spindle slowing to 4-8 RPM. Checked voltage at spindle drive = 0.0. Jogged both axis'. Still 0.0V.

If I had a different spindle drive I would try it. If I had a different Kanalog I would try it.

What do these tests indicate to you?

Thanks again and again.

[TomKerekes]

Hi Charles,

Dac6=200, unloaded, checked -.985V.
Dac1=-2047, unloaded, checked 9.88V.
Connected 1 Kohm resistor between DAC1 and Dac6. Dac6 was pulled upward to -.980 or 5mV change.

This would indicate Kanalog DAC6 is working correctly. I'm not sure why you tested DAC6 as the Spindle uses DAC3 or DAC4?

Connected multimeter set to DC amps between Kanalog ground and spindle drive input. Meter reading was .001. Jogged X and Z, reading did not change.

This would indicate the drive is not back feeding any current. But I'm a little suspicious of your meter showing 0.001 and not changing at all. If the meter is on a 10Amp scale then it probably won't work for what we are trying to measure. You might check the meter by doing the test you did earlier with 11V across a 1K Ohm resistor. Putting the meter in series with the resistor should show 11ma of current.

If your meter can't measure milliamps then you might use something like a 100 ohm resistor in series with the circuit. Then measure voltage across the resistor. Then for example 11ma of current through a 100 Ohm resistor should read 1.100V


So what seems strange and inconsistent to me is if I understand correctly we previously connected X Z normally, commanded some voltage like zero to the Spindle DAC without anything connected to the Spindle DAC. And with the Spindle Command connected to kanalog GND. When Jogging X or Z the Kanalog Spindle DAC output did not change. But when connecting the Spindle DAC to the Spindle Input instead of Kanalog GND then Jogging X Z causes the Spindle DAC Output to change by 70mV. So if there is no current flowing through the Spindle Command wire how could it affect Kanalog whether it was connected or not?

If you contact our support and tell them where to ship it they can send you another Kanalog to see if that makes a difference.

[Charles2]

Hi Tom,

I have used Dac2,3,4,and 6 for the spindle, just trying to find a different result. Dac6 seems to have the least voltage with 0 commanded.

I too am suspicious of the meter. Not a nice Fluke 87 like I had when I was working. Just a cheap Southwire from Lowes. I don't think it can read milliamps.

I will retest as you suggested.

This morning I have been on a mission for grounding and interference possibilities.
I rerouted the USB cable outside of the cabinet. Soon all my wiring will be outside the cabinet.

Reconnected the spindle encoder shield at Kanalog. Found that it was connected at the encoder plug and disconnected it there.

Axis encoder shields are also connected at the encoder, so I disconnected them at Kanalog.

Connected a wire from the spindle drive shield terminal, where the command and tach shields are attached, to chassis ground.

Just a thought, maybe I should disconnect the spindle tach?

Added a ground wire from spindle motor to chassis ground.

Axis motors test as grounded to chassis.

There is a 44mV difference between Kanalog and chassis, X and Z drive grounds, spindle drive command shield, and spindle drive ground test point. I'm sure I've seen that Kanalog should not be grounded. Is it ok to have this difference?

At this point, everything is 'star' grounded except Kanalog. This includes axis power supply chassis, X and Z drives, spindle drive shield terminal, and spindle motor.

I will retest as you suggested before I contact support for a new Kanalog.

Thanks