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Author Topic: delta ac servo and Mach  (Read 15885 times)

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Re: delta ac servo and Mach
« Reply #10 on: May 21, 2013, 11:43:54 AM »
Hi Guys,

I came across this thread as I'm busy trying to set up the exact same drives for a client using Mach3 as they are unhappy with their PLC control solution. I've been looking at the datasheets and it looks like there is an option to use single-ended step and direction signals for a breakout board. Please see the attached application note. My only question is...which signal is step and which is direction? PULSE or SIGN?? Lets try get this interface solved as I'm sure it would benefit quite a few other users.

Thanks!
Re: delta ac servo and Mach
« Reply #11 on: May 21, 2013, 11:46:22 AM »
And I note that we would need to add a PNP transistor for each signal :) But that is straight forward and cheap.

Please correct me if my assumptions are wrong. I'm referring to the first diagram in the attached file.

Thanks again!
Re: delta ac servo and Mach
« Reply #12 on: May 21, 2013, 12:18:17 PM »
        STEP = PULSE
DIRECTION = SIGN
Re: delta ac servo and Mach
« Reply #13 on: May 21, 2013, 12:24:33 PM »
Appreciated,

But I have seen a reference in some of their documentation that PULSE is direction. I know, makes no sense to me either, but it does say it. So I'm hoping that you've set up a drive with STEP = PULSE and DIR = SIGN? That would make my life much easier :)

Thanks again.
Re: delta ac servo and Mach
« Reply #14 on: May 21, 2013, 12:32:37 PM »
Yup ... Automation Direct, SureServo.
(seen a couple others also)
Russ
Re: delta ac servo and Mach
« Reply #15 on: May 21, 2013, 12:34:23 PM »
Ha, superb.

Thanks very much. I'll post the connection diagrams here for reference once the setup is done and tested.

CIAO
Re: delta ac servo and Mach
« Reply #16 on: September 01, 2013, 03:51:39 AM »
Just an update on all of the above. Step/Direction issue resolved. Trying today to connect the step and direction from a 5V BoB with NO Line Driver. So just single-ended 0-5V. I appreciate that this is not too noise immune and it may not work at all. There are two 51ohm resistors either side of the optocoupler input diode inside the Delta ASDA-B2 drive. If you do as they say with the line driver, that is a 10V differential across these resistors in series. Gives about 0.04901A, or 49mA of current by their (Delta's) design to switch the optocoupler. HOWEVER... we do not have access to the tech. specs. for the optocoupler which they use and it is my suspicion that using single-sided input (0-5V) may just work. It is obviously not ideal, but it will still give 24.5mA across the optocoupler diode which may still be enough to switch it on. The only place I see a problem with this is that at high speeds there won't be good step clarity and it may result in lost steps to the drives. (To the drives, not to the motors, which are obviously closed-loop). So, in summary, I will test this now and my guess is that provided we stay below 100kHz pulse trains (200kHz is the spec.) that it should be ok. Will post updates shortly. (I note again that you will need EXCELLENT noise shielding to do this and not lose steps.)
Re: delta ac servo and Mach
« Reply #17 on: September 02, 2013, 11:37:28 AM »
Right, so as promised, I did the setup and testing. Delta ASDA-B2 400W drive works perfectly well with single-ended inputs. NO LINE DRIVER. And it's reliable too. No lost steps between Mach 3 and the drive control loop. I was pleasantly surprised as to how well it worked actually. I applied a constant 5V supply to pins 39 and 43 of the CN1 connector of the drive and connected STEP and DIRECTION signals from my BoB (Cheap Chinese thingy... the cheapest ones on E-Bay) to pins 37(DIR) and 41(STEP) of the CN1 connector on the servo drive. In Mach, I simply assigned the step and direction pins as per the BoB and made sure that the pulse width was 5us and that the gap between pulse and direction change was 5us under 'motor tuning'. The drive is set up as 17bit from factory (132000 and something steps per rev) so I had to go into the drive configuration software and electrically gear this down a bit so that the Mach kernel speeds could actually get the motor spinning at 3000rpm. All done though and working great. Hope this helps some others struggling with the config.