Need help with TB6560
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25 Dec 2016 05:26 - 25 Dec 2016 09:30 #84675
by LS
Need help with TB6560 was created by LS
I'm configuring a 5i25 to interface with a parport BoB. It's a YOOCNC-NT65-3X from a YOOCNC 4030 machine.
I've read conflicting information about the step pins, so I'm not sure if they are active-low or active-high (at the DB25).
PDF schematic attached
Here are some quick observations:
Both seem to "work", but which is correct?
I've read conflicting information about the step pins, so I'm not sure if they are active-low or active-high (at the DB25).
PDF schematic attached
Here are some quick observations:
- Active-low appears to harder to turn by hand while they are idle. Emits a slight noise from the steppers. The steppers feel hotter.
- Active-high is easier to turn by hand while they are idle. No noise from steppers.
Both seem to "work", but which is correct?
Last edit: 25 Dec 2016 09:30 by LS.
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25 Dec 2016 10:23 #84678
by andypugh
Replied by andypugh on topic Need help with TB6560
The torque when not stepping should not depend on the polarity of the step pins at all.
Not-stepping should just lock the motor in the last-commanded position.
The schematic shows the pins pulled-up to 5V then inverted by a 74HC14 before being sent to the low-side of an opto-isolator.
I think you might need to work backwards from the TB6560 as it goes through so many inversions on the way.
Not-stepping should just lock the motor in the last-commanded position.
The schematic shows the pins pulled-up to 5V then inverted by a 74HC14 before being sent to the low-side of an opto-isolator.
I think you might need to work backwards from the TB6560 as it goes through so many inversions on the way.
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25 Dec 2016 13:42 - 25 Dec 2016 13:58 #84680
by LS
Replied by LS on topic Need help with TB6560
Yep, I've just been working backwards from the TB6560.
1. The TB6560 steps on a rising edge of the CLK.
2. The 6N137 inverts the signal, but since the input is fed into the cathode the net result is non-inverted.
3. 74HC14 inverts the signal.
Overall, the DB25 step signal would need to be active-low (contradicting the manual).
I'm not sure how to interpret the circuit controlling the torque inputs TQ1 & TQ2. Seems that it toggles the torque signal on step signal? Might have something to do with the heat generated on the steppers for active-low?
1. The TB6560 steps on a rising edge of the CLK.
2. The 6N137 inverts the signal, but since the input is fed into the cathode the net result is non-inverted.
3. 74HC14 inverts the signal.
Overall, the DB25 step signal would need to be active-low (contradicting the manual).
I'm not sure how to interpret the circuit controlling the torque inputs TQ1 & TQ2. Seems that it toggles the torque signal on step signal? Might have something to do with the heat generated on the steppers for active-low?
Last edit: 25 Dec 2016 13:58 by LS.
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27 Dec 2016 15:01 - 27 Dec 2016 15:03 #84748
by LS
Replied by LS on topic Need help with TB6560
After some further analysis, it appears they are trying to control torque by the CLK (STEP) input.
[Refer to attachment]
Orange = CLK
Green = TQ1 & TQ2
TQ1/TQ2 HIGH = 20% torque
TQ1/TQ2 LOW = 100% torque
For the TB6560, stepping occurs on the rising-edge of CLK. The confusing part of all this is that every CLK rising-edge, the torque is at 20%...
Maybe there a fault in their circuit?
[Refer to attachment]
Orange = CLK
Green = TQ1 & TQ2
TQ1/TQ2 HIGH = 20% torque
TQ1/TQ2 LOW = 100% torque
For the TB6560, stepping occurs on the rising-edge of CLK. The confusing part of all this is that every CLK rising-edge, the torque is at 20%...
Maybe there a fault in their circuit?
Last edit: 27 Dec 2016 15:03 by LS.
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27 Dec 2016 16:59 #84755
by andypugh
It's not impossible. Though they seem to have a lot more of the circuit than is normal, and this might be a sign that they are trying to do a good job.
There is an RC network with an 8µS time constant on the TQ inputs, but that seems too short for a current-lowering circuit (which many drivers use).
Replied by andypugh on topic Need help with TB6560
Maybe there a fault in their circuit?
It's not impossible. Though they seem to have a lot more of the circuit than is normal, and this might be a sign that they are trying to do a good job.
There is an RC network with an 8µS time constant on the TQ inputs, but that seems too short for a current-lowering circuit (which many drivers use).
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28 Dec 2016 04:11 #84785
by LS
Replied by LS on topic Need help with TB6560
Today I used the DMM to perform some basic logic checks on the circuit board. The circuit logic appears to be correct, so it's more likely there's a bug in the schematic diagram instead.
The torque is minimised while idle (CLK=HIGH; TQ=HIGH. When a step command is issued, the CLK goes LOW, which brings TQ LOW (increasing torque), then on the rising edge of CLK a step occurs. I'd say the 8µS time constant holds the torque pin LOW (100% torque) after the rising-edge clock to ensure there is full torque throughout the step action. I'd need to borrow a logic analyser to watch whats going on during operation .. a job for another day.
To answer the original question .. the step pins are active-high.
Cheers
Luke
The torque is minimised while idle (CLK=HIGH; TQ=HIGH. When a step command is issued, the CLK goes LOW, which brings TQ LOW (increasing torque), then on the rising edge of CLK a step occurs. I'd say the 8µS time constant holds the torque pin LOW (100% torque) after the rising-edge clock to ensure there is full torque throughout the step action. I'd need to borrow a logic analyser to watch whats going on during operation .. a job for another day.
To answer the original question .. the step pins are active-high.
Cheers
Luke
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