Installation guide

Whistle/Tweeter Installation Guide Installation
MAN-WHTWIG (Ver. 1.5)
3-7
3.5.2 Grounds and Returns
The “Returns” of the Whistle and Tweeter are structured internally in a star configuration.
The returns in each functional block are listed below:
Functional Block Return Pin
Power PR (Power Return)
Internal Switch Mode P.S. PR (Power Return)
RS232 Communications RS232_COMRET (J1/3)
CAN Communications CAN_COMRET (J1/20)
Control section Internal, not accessible
Main Feedback SUPRET (J2/2)
Aux. Feedback SUPRET (J1/4)
Analog input ANLRET (J2/2)
The returns above are all shorted within the Whistle and Tweeter in a topology that results in
optimum performance.
1. When wiring the traces of the above functions, on the Integration Board, the Returns
of each function must be wired separately to its designated terminal on the Whistle or
Tweeter. DO NOT USE A COMMON GROUND PLANE. Shorting the commons on
the Integration Board may cause performance degradation (ground loops, etc).
2. Inputs: The 6 inputs are optically isolated from the other parts of the Whistle and
Tweeter. All 6 inputs share a single common “Return” (INRET - J1/15). To retain
isolation, the Input Return pin, as well as other conductors on the input circuit, must
be laid out separately.
3. Outputs: The 2 outputs are optically isolated from the other parts of the Whistle and
Tweeter. Each output has a separate floating return (OUTRET1 - J1/17 for output 1
and OUTRET2 J1/16 for output 2). To retain isolation, the Output Return pins, as well
as other conductors on the output circuit, must laid out separately.
4. Return Traces: The return traces should be as large as possible, but without shorting
each other, and with minimal cross-overs.
5. Main Power Supply and Motor Traces: The power traces must be kept as far away as
possible from the feedback, control and communication traces.
6. PE Terminal: The PE terminal is connected directly to the Whistle’s heatsink or to the
Tweeter's 2 PE strips on its lower board. In the Whistle, the heatsink serves as an EMI
common plane. The PE terminal should be connected to the system’s Protective Earth.
Any other metallic parts (such as the chassis) of the assembly should be connected to
the Protective Earth as well.