Dynomotion

Group: DynoMotion Message: 12384 From: seth7baseball Date: 10/12/2015
Subject: Kanalog Grounding
Hi all,
Does someone know how the FET Watchdog and the other eight relay drivers are grounded to Kanalog?  Right now the wiring schematic goes from:  +24V (supply has floating ground)>>>>load(which enables servos)>>>>>Kanalog Pin 9 on JP8 (SwitchEnableAll)
I am assuming the "SwitchEnableAll" is the watchdog relay enabler. Is there a connector on Kanalog to ground the FET relay enablers back to the 24V common? Or does it ground to earth ground through the standoffs? 
And does this mean I should be earth grounding the 24V and 5V common on my power supplies? I have heard it is best to try to avoid this for noise issues in the circuit.  Any advice on this would be appreciated.
Thanks,
Seth
Group: DynoMotion Message: 12385 From: Tom Kerekes Date: 10/12/2015
Subject: Re: Kanalog Grounding
Hi Seth,
The 8 Relay drivers are open collector type (switch to GND) capable of switching loads up to 1Amp at up 24V.  They share a common GND with Kanalog (are not isolated).  The outputs on Kanalog are not guaranteed to power up off until after KFLOP has booted.  The additional SWE relay driver should be used as a master enable to avoid momentary power up issues.  SWE is guaranteed to remain off until after all the Kanalog Outputs have been initialized off.

Kanalog has a single GND common to KFLOP, control logic, relay drivers, and Analog signals.  The GND should normally be isolated from Earth GND to avoid ground loops and injecting earth GND noise into Kanalog/KFLOP DC GND.  Standoff mounting holes are completely isolated with the exception of the GND lug holes marked "GND".

The Opto Inputs and Outputs are fully isolated.

HTH
Regards
TK