Standard practice is to ground the negative rail. However, the : “For redundant parallel operation, do not connect V- to ground at more than one point.” Violation creates ground loops and erratic error E-103.
That is the high-reliability variant with conformal coating. The standard manual applies to both, but the HR version has an additional note on page 67 regarding vibration tolerance (5g vs 2g). bsmce04u-pp manual