Bridgeport Interact 4 Series 2 to Acorn6 build

[suntravel]

If this is also nok, you can use a TTL to RS422 converter and connect the driver to the differential signal.

Uwe

[richardb15]

Uwe, thank you very much for the info. I sneaked off into the workshop to satisfy my curiosity on this. After a bit of changing I could see the pulse width increasing, but I ended up with P968=30 (12 microsecond pulse) before the drive started working. But, its working! It confirmed my suspicion that the 2.5us was too small for the H2-2206. All good, onwards and upwards

[suntravel]

with only 40000 Hz you will not get decent rapid speed...

Uwe

[richardb15]

with only 40000 Hz you will not get decent rapid speed...

Uwe

Well the machine original spec was a 5000mm/min maximum rapid feed. At 40kHz, 1:2 belt ratio and 5mm ballscrew pitch if my calcs are correct I can set the axis motor drives to 1200steps/rev. That will give 5000mm/min rapid feed, and a single pulse resolution of 2 microns which are both quite enough. Actually to build the machine I'll be using two H2-2206 drives and three HBS2206 so always the option to use the faster HBS drives on the linear axes and the slower H2 ones on the (eventual) rotary table.

That leads me to another question, the P968 seems a universal parameter, is it possible to set different values for different axes?

[suntravel]

P968 is for all axes.

Milling and Lathe Machine Happy Zone.
- Happy Zone Overall Turns Ratio for milling machines and lathes is 5 to 10 turns of the AXIS MOTOR yields 1" of table/gantry movement.
- Steps Per Revolution of 3200 or higher.
- Axis motor Accell/Decell .375 - .5 seconds
- CNCPC CPU with single thread benchmark of 1500 or higher

viewtopic.php?f=63&t=1801&p=11936&hilit ... ill#p11936

I would crap this driver and use a better one.

My machines are with 5mm pitch 2:1 reduction and 4000 steps.
4000 or 8000 steps is the best setting for CL Steppers with 1000 Line encoders

Uwe

[eng199]

The 2.5us high and low means this drive is rated for 200kHz step rate, which is common for stepper drives. Step pulses are only 50% duty cycle at maximum rate. Each step pulse is a fixed width based on the maximum step rate. 200kHz (the default, P968=0, or P968=6) is the correct setting according to the 2.5us specification in the manual.

The 'scope shot shows a poor quality signal. This is probably what is limiting the step rate. 10k pull up is not sufficient current for 5V signals. Try 470 ohm or lower, down to 100 ohm at minimum. Alternatively, use the 5V logic level outputs without resistors. Unusually large wire gauge or wire length can also increase capacitance and make the inputs harder to drive.

[richardb15]

Thanks for the additional input. I'm using the 5V logic outputs with no resistors. I know the H2-2206 drive manual says 2.5us..... but clearly its not! The HBS2206 drive is a later version of the H2-2206 so it seems the later ones are fine at 2.5us pulse length so Leadshine must have done some update. I know these are both legacy drives. In effect the 5 drives I have and the motors all came out of a scrap pile so I got them for free. The H2-2206 are probably 10 years old at least, and the HBS2206 are maybe 8 years so out of date, obsolete, but free. I've spent up on the Acorn6 etc so in the future I may update the axis drives and motors to something more modern but budget says no this year. I'll just be happy to get the machine up and running and paying itself back. I don't really care about extra fast rapid speeds right now. If it works and is repeatable/accurate that will be okay.

Next job, get the VFD working if I can, again free/scrap, but worth a shot. Once I have a spindle drive/motor in operation on the bench its install time.

[suntravel]

Setting up a machine outside the happy zone is not ok if you want good surface quality and good precision.

Uwe

[richardb15]

Setting up a machine outside the happy zone is not ok if you want good surface quality and good precision.

Uwe

Message received and understood. It is a real shame the CNC12 does not allow each axis to be configured with independent P968 values, surely I'm not the first person to ever use a mix of drives in a machine fitted with Centroid. Anyway, I have what I have to work with. I'm going to set up the X and Y with the HBS2206 and HSM100 motors so they match and will take a 200kHz input okay, as any mismatch on those will not produce good circular interpolation if any latency is present. I'll use the less critical H2-2206 and a mix of HSM100 and HSM80 on the Z, W and rotary axes. To use the CNC12 at 200kHz won't work with the H2-2206 drives as-is but to gain that speed I think I can install a simple 74HC123 circuit in the step line as that will take a nanosecond pulse and convert it to whatever I set the R&C values to produce. I can then just set P968=0 and run different rapid speed limits on each axis as required so works around the P968 one-size-doesn't fit-all issue. $10 of components vs $$$ for new drives and motors.

Back onto the project today I was going to leave the original mechanical relays in, but the wiring was such a rats nest, and the Acorn6 has 16 relays neatly set up already I decided just to take them all out.


I'm keeping the original limit, home, e-stop and tool change buttons so have just left them wired at the switch ends, I'll trace them to the loose ends and reuse the 110 existing connections in the left hand terminal block, just keeping records and what goes where.





I did wire the CHRH VFD up for bench testing and connected it up to the 5kW motor on my crank grinder just to see if it worked at all. Well it does, I can start, stop, fwd, rev and adjust speed up to 50Hz using the front panel on the drive but haven't managed to figure out how to get it above 50Hz yet, or work from a 0-10v input. It has 130 parameters that I've made a copy of so I can start playing about now and just change each one, observe the result, and note what it does.

[richardb15]

Some nice progress, always good to be putting things back into a cabinet!



I've added a cable run up the right hand side to take all the 240v and 415v. I can then run the signal and control on the left hand side keeping them with good separation. All power control along the top with a new DIN rail. I've reused the original T1 transformer, DC rectifier and DC vreg but ditched the fueses and run everything via breakers, all along the top of the cabinet. This now gives me 3ph 415v, a neutral, 110vac, 50vac and a 36v DC unregulated and 24vdc regulated all set to be enabled when the main cabinet breaker is turned on.

Next step is to install a couple of contactors, one that will act as a master for the whole machine via momentary on and off buttons on a control panel, and a second one that will be the e-stop contactor to turn the drives and spindle off if stuff goes awry, but leave the acorn6 and PC live.