Messages

1

dspMC/IP Motion Controller / Re: DSPMC SIGNAL STAR GROUNDNG FOR ANALOG DRIVES

« on: April 04, 2020, 11:17:43 PM »

image4 = controller powered only, 24V power supply -com connected to earth ground

image5 = servo drives powered, enabled, and jogging servo one direction continuously,24V power supply -com connected to earth ground, wow looks better! i can see how the signal works now the amplitude of the square wave increases as speed increases.

image6 = servo drives powered, enabled, and jogging servo one direction continuously,24V power supply -com connected to earth ground,higher rpm jogging distorts the signal like a wave, also the entire  signal moves up and down slightly some other noise issues i suspect! DC offset??  but could be PID adjusting the signal not sure that works.

On this old CRT oscilloscope  you cant see vertical lines,
by the way I'm only measuring dc signals staying clear of ac high power!

edit: sorry last pic is blurry chose the wrong picture

2

dspMC/IP Motion Controller / Re: DSPMC SIGNAL STAR GROUNDNG FOR ANALOG DRIVES

« on: April 04, 2020, 10:57:08 PM »

hi,
   So i had this crazy idea! I've got this old hitachi 20MHz oscilloscope pulled it out of the cupboard wiped off the dust and fired it up
connected THE main oscilloscope lead to  +/-10V analog0 and alligator clip to analog GND on controller this what i got:

image1 = controller powered only , thinking this is strange doesn't look right

image2 = servo drives powered,not enabled, thinking looks like high voltage lightning at the top and bottom of the weird square wave,  looks cool but very wrong

image3 = servo drives powered, enabled, and jogging servo one direction continuously, if you look closely you can see little teeth on the square wave

see next post

3

dspMC/IP Motion Controller / Re: DSPMC SIGNAL STAR GROUNDNG FOR ANALOG DRIVES

« on: April 03, 2020, 11:11:22 PM »

hi,

Here is a link the the manual
http://www.vitalsystem.com/portal/motion/dspmc/DSPMC.pdf

page 24

cheers

4

dspMC/IP Motion Controller / Re: DSPMC SIGNAL STAR GROUNDNG FOR ANALOG DRIVES

« on: April 03, 2020, 10:03:30 PM »

hi,
Sorry been away from computer
Thank you for taking the time to reply!
just a note this is a hobby so far for me so electronics this is not my career
I plan to get a qualified electrician to look over my work

To MN300,
          I value the information provided it makes perfect sense to me thank you
its now how i have it wired,

but can you explain what the example in the dspmc Manual  analog servo drive connection is all about
because it contradicts what your saying ?
is it for connecting older style simple servo amplifiers ?

My dspmc has analog inputs also if they are temporally unused  is it ok to leave them floating?
will they introduce noise ?

Thanks again

5

HiCON Motion Controller / 7535N and 7737 boards pcb vias

« on: April 01, 2020, 10:11:00 PM »

hello,
     Can anyone confirm if the mounting hole pcb vias in 7535N and 7737 boards should be mounted electrically to an earth grounded panel?
or should they be isolated?

cheers

6

dspMC/IP Motion Controller / Re: DSPMC SIGNAL STAR GROUNDNG FOR ANALOG DRIVES

« on: April 01, 2020, 05:06:15 PM »

Thank you for taking the time to reply.
I'm not trying to create problems, i'm trying to understand.
i not trying to offend you ether.

yes the dmm manual Shows nothing to connect AIN- to somewhere else.
it also shows the shield of ain+ and ain- connected to JP4 shell
but like you have already mentioned connecting the shield to ground at the output side makes a lot more sense
its what i will do.
 The dspmc manual shows otherwise please see attached pdf, any thoughts on this ?

it also says relating to this attachment:

in order to filter the electrical noise from motors, drives and vfds, the GND (common)pins  on j2....j7 should be tied to the
earth ground at multiple points.
the following example shows GND pins on j2 tied to earth ground.
in addition, the power supply negative terminal should also be connected to any of the j2..j7 GND pins at two or more
terminals

yes those interface modules are great!! i have a few already in use

Best Regards

7

dspMC/IP Motion Controller / Re: DSPMC SIGNAL STAR GROUNDNG FOR ANALOG DRIVES

« on: April 01, 2020, 09:20:23 AM »

hi,
Thanks a lot for you feedback got me thinking
are you sure AIN- on dyn4 is isolated ? looks like its an opamp?


Com pin 5 on dyn4 is opto isolated so shouldn't connect to signal Gnd ?
have attached a simplified version is this what you mean ?

cheers

8

dspMC/IP Motion Controller / Re: DSPMC SIGNAL STAR GROUNDNG FOR ANALOG DRIVES

« on: March 31, 2020, 05:54:24 PM »

hello, thanks for your reply,
I understand the cable shielding should be grounded only at  the analog  source  end of a shielded cable,
what i'm  having trouble understanding is interpreting the schematic for properly grounding the entire system
in this instance should i keep common from dc power supply isolated from  service earth ground
and then run multiple earth returns from j2..j7 to earth ground and separately to  common ground?

Best Regards

9

dspMC/IP Motion Controller / Re: DSPMC SIGNAL STAR GROUNDNG FOR ANALOG DRIVES

« on: March 31, 2020, 08:35:14 AM »

Anyone know how this works ?
cheers

10

dspMC/IP Motion Controller / Re: DSPMC SIGNAL STAR GROUNDNG FOR ANALOG DRIVES

« on: March 31, 2020, 08:31:36 AM »

EDIT3