DB9/G540 questions

[JC50]

Getting ready to wire up my motors to the G540. I'm using 22 AWG 7 strand shielded cable. This cable has one pair shielded separately inside the jacket, and then all 7 wires are covered by another shield. My question. Should the shields be connected to anything, and if so, what.

Also, the G540 manual says to ground pins 2, 3 & 4 of the DB9 connector. I'll be shorting those three pins together and just use one wire back to ground. Stupid question, as I'm pretty sure I know the answer, but does this ground go back to the VDC- of my PSU.

[cornbinder23]

Ground the shield to those pins in the DB9 and tie ALL grounds to the same place in your cabinet, only ground the shield at the driver end not the motor end
DISCLAIMER: I am not an electronics expert but this is the advice that was given to me and it has worked flawlessly on my system for almost 2 yrs now


JTCUSTOMS

[TheBulk]

Sorry to Highjack your thread but when you say ground to the same spot on the cabinet I'm not sure I am understanding you.

When I ground a gas line I drive a 3 foot steel stake into the ground and connect it to that, When I ground myself to my computer to do work in it I connect an aligator clip to myself and the other end to the shell of the computer.

Where does the other end of the ground wire connect to? The reason I ask this is because aren't pins 2,3 & 4 on the DB9 connected to Ground return inside the G540 so therefore there should be no need to connect the shielding to anything other than them?

Thanks in advance and again sorry for highjacking

Andrew

[cornbinder23]

If the ground on your input lines (AC) and your DC side are all connected then all the grounds should be at the same potential.
If you motor ( spindle ) is a three prong than the ground "should" also be at the same ground potential
All of these will also tie back to the ground rod on the main service, as that is connected to the ground plane in the breaker panel


hopefully this makes sense

JTCUSTOMS

[cornbinder23]

I am not sure I understand the question

The grounds on the DB9's all tie back to the main grounding lug in the panel
through the G540, the "shield" is just a drain for the multi conductor cable

JTCUSTOMS

[Al_The_Man]

Originally Posted by JC50 Should the shields be connected to anything, and if so, what. Also, the G540 manual says to ground pins 2, 3 & 4 of the DB9 connector. I'll be shorting those three pins together and just use one wire back to ground. Stupid question, as I'm pretty sure I know the answer, but does this ground go back to the VDC- of my PSU.

Confusing isn't it?
Unfortunately the term ground has come to be rather meaningless as it does not qualify the reference or what supply the 'Ground" is refereing to.
Especially if you are tieing in separate sytems, BOB's, Drives etc that refer to 'Ground' what does that mean?
Are these 'Grounds' all the same? Are they at Earth Ground or ?
Gecko mentions several terminals as Ground but does not qualify if if is a certain supply common or if it is, or not at Earth Ground?.
To avoid misunderstanding, IMO It is preferential to indicate a power supply common, i.e. 5v common, or 48v common and indicate if this is recommended to be connected to Earth ground or not.
Shield's should be connected to Earth ground or a central point where your service panel Earth Ground conductor comes into your system.
Al.