Hello Guest it is April 15, 2024, 08:20:43 AM

Author Topic: DSPMC SIGNAL STAR GROUNDNG FOR ANALOG DRIVES  (Read 5083 times)

0 Members and 1 Guest are viewing this topic.

DSPMC SIGNAL STAR GROUNDNG FOR ANALOG DRIVES
« on: March 30, 2020, 10:10:55 PM »
Hi all,
Ive owned my dspmc for about 4 years running stepper motors,
sadly it is discontinued,
now i have dmm servos running on  +/- 10V analog torque mode
but im still confused about star grounding  multiple drives please if any one is still running  a dspmc a little help to understand
would be much appreciated!

is my real world ground wiring  interoperation of star grounding multiple servo drives with dspmc  correct ?
things that I'm most confused with are:

should my signal (com) ground bus be bonded to my earth ground power bus?
how to test if my switch mode power supply is already internally got com bonded to earth ground creating a ground loop? 
ground symbols in AnalogDriveConections.pdf from vital systems   don't seam to match standards  eg, attached image

taken from the dspmc manual :

Quote
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

trying to achieve this without creating ground loops not so easy
best regards
Amyl
Re: DSPMC SIGNAL STAR GROUNDNG FOR ANALOG DRIVES
« Reply #1 on: March 30, 2020, 11:21:46 PM »
UPDATED  INTERPERTION STAR GROUND
to include j7
Re: DSPMC SIGNAL STAR GROUNDNG FOR ANALOG DRIVES
« Reply #2 on: March 31, 2020, 12:48:50 AM »
or should it be done this way?
Re: DSPMC SIGNAL STAR GROUNDNG FOR ANALOG DRIVES
« Reply #3 on: March 31, 2020, 08:31:36 AM »
EDIT3
Re: DSPMC SIGNAL STAR GROUNDNG FOR ANALOG DRIVES
« Reply #4 on: March 31, 2020, 08:35:14 AM »
Anyone know how this works ? :o
cheers

Offline TPS

*
  •  2,505 2,505
    • View Profile
Re: DSPMC SIGNAL STAR GROUNDNG FOR ANALOG DRIVES
« Reply #5 on: March 31, 2020, 03:36:43 PM »
normaly you put  all chasis grounds to your earth potential.

for a anlaog Signal you use a two wire (twisted) shielded cable from the
source to the Destination and shield should be wired to the GND of the source
(of cource i hear all the voices witch say do no do this), but for a good start
it was the best soluition for me for the last 35 jears.
anything is possible, just try to do it.
if you find some mistakes, in my bad bavarian english,they are yours.
Re: DSPMC SIGNAL STAR GROUNDNG FOR ANALOG DRIVES
« Reply #6 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

Offline TPS

*
  •  2,505 2,505
    • View Profile
Re: DSPMC SIGNAL STAR GROUNDNG FOR ANALOG DRIVES
« Reply #7 on: April 01, 2020, 02:56:54 AM »
i would prefer to run AIN- and AIN+ directly via 2 wire shielded / twisted cable to the Motion Controller and
put shield on Motion Controller side to GND. the analog Input of your dmn dyn4 is isolated so do not connect
AIN- to Signal ground bus.

anything is possible, just try to do it.
if you find some mistakes, in my bad bavarian english,they are yours.
Re: DSPMC SIGNAL STAR GROUNDNG FOR ANALOG DRIVES
« Reply #8 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

Offline TPS

*
  •  2,505 2,505
    • View Profile
Re: DSPMC SIGNAL STAR GROUNDNG FOR ANALOG DRIVES
« Reply #9 on: April 01, 2020, 02:10:54 PM »
if you have a quick look to the dyn4 Manual it says clearly that all Input signals are isolated.
also the example wiring diagram of the analog Input Shows nothing to connect AIN- to somewhere else
as the analog out ground of the source.

so why are you trying to create Problems ?
anything is possible, just try to do it.
if you find some mistakes, in my bad bavarian english,they are yours.