Encoder Wiring

Tommylight -- so connect drain to chassis then?

Edit: the analog servo drive connection recommends connecting the drain wire to GNDN, is this a different case?

RT

cngbrick wrote:

Tommylight -- so connect drain to chassis then?

Edit: the analog servo drive connection recommends connecting the drain wire to GNDN, is this a different case?

RT

Yes and no.
Yes connect to GROUND or chassis ground, and no that is not a drain.
Take PCW's advice and leave it not connected, do some testing and if you get interference, then tie it to ground.
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And i do understand the confusion, the internet is full of useless and plain wrong information's, especially calling the 0V or common rail "GND" or "ground", it is not.
GND or ground should be used only for the wire that actually and literally goes into the ground.
Oh well, modern era of misinformation is upon us ...

Part of my confusion comes from the following instructions in the 7i97 manual:

"Suggested wiring is shielded twisted pair with7I97 AOUTN to drive
AIN+, 7I97 GNDN (adjacent to AOUTN) to drive AIN- as the twisted pair and 7I97 GNDN
connected to the shield at the 7I97 end only. The drives common or GND signal should be
connected to the 7I97 power GND with a separate wire."

This relates to the analog servo interface, but nonetheless there is a suggestion that the shield should be connected to a GND terminal pin on TB3. Is this a case of misleading terminology and how is this different than the encoder connections on TB1 and TB2?

RT

Analog servo interface is completely separated from other stuff, so it has it's own rules, usually there is analog ground and digital ground on them.
Encoders are simple, connect the shielding only on the controller side to actual ground. Most of the time it works even without connecting the shielding at all, but high power stuff causes plenty of interference making use of it mandatory.