clunks / missing steps - DM856 and single pulse operation

[dsc]

Yes I've had it connected to a pulse generator earlier on, but of course that's a source output rather than a sink, it seemed to work ok I think, I will upload a video later on with a pulse genny on the DM856.

The motor just sits on a desk, I can probably clamp it down for further tests.

As I said before the PIC is powered from a plug-in 9VDC power supply, which is connected to the same 230VAC source as the 68VDC PSU which powers the motor / driver.

On the 7805 I have 9VDC on the input and 5.01VDC on the output.

Regards,
T.

[EddyCurrent]

Having read you previous posts I am surprised you say this

As I said before the PIC is powered from a plug-in 9VDC power supply, which is connected to the same 230VAC source as the 68VDC PSU which powers the motor / driver.

because it doesn't matter about that, it's the output dc grounds that have to be connected.

[dsc]

Why is that? what I meant to say is that eventually it all comes down to the same 230VAC connection, so ground on both should be at the same potential. Or am I missing something obvious?

Regards,
T.

[FatFreddie]

Why is that? what I meant to say is that eventually it all comes down to the same 230VAC connection, so ground on both should be at the same potential. Or am I missing something obvious?

It doesn't quite work like that, it's sort of complicated depending on earthing arrangements etc but you definitely need the DC grounds (maybe a bad term - DC 0v is better) connected.

[EddyCurrent]

Well I was surprised because it looks like you know what your about but it may be I'm at cross purposes.
I'm on about this.


But I then realised you might be saying this;

"I'm using the same power supplies for both the DM856 and the HBS86 tests"

[Jonathan]

Since the drive inputs are optically isolated, you shouldn't connect the PIC DC ground to the driver supply DC ground as that looses isolation. I think there could easily be enough noise on the driver DC ground to cause incorrect signals on the inputs if you tied them together.

What you're trying to do should take about 5 minutes, not days, so there's probably something simple we're missing. Could you carefully draw out the complete schematic of what you've set up?

On the 7805 I have 9VDC on the input and 5.01VDC on the output.

I'm pretty sure Irving was asking to find what capacitors (if any) you'd put on the input and output of the 7805. The datasheets give typical values, which should be fine for this.

The 'clunking' you describe is normal at low speed, since the motor stops after every step. At high speeds a good driver will run the motor in a different way with continuous angular speed, so you wont hear the steps.

[dsc]

Ok then, here's a connection diagram:



I'm using this as power supply:

Solderless MB-102 Breadboard Power Supply - Dual 5V and 3.3V DC Jack and USB New | eBay

As it can be used on a breadboard, had enough faffing about with 7805 on their own (too thick legs to fit on a breadboard). Not sure about what capacitors it's using, as it's all tiny SMD stuff.

I'm using the SPS705 unregulated power supply from Leadshine (Zapp) and used it on both the DM856 and the HBS86.

The only other thing is the setting on the DIP switches for the current, I was told by Zapp to set it to 2.1A peak, currently it's software configurable, but I can't connect to the driver as the software package from Leadshines drops the RS232 connection for some reason when I view the config of the driver.

Regards,
T.

[Jonathan]

What you've drawn look fine to me.
Have you put a decoupling capacitor adjacent to the PIC? e.g. 0.1uF capacitor across VSS and VDD.