Logic Solvers, SISNet Repeaters, and SISNet Distance Extenders are powered separately from DeltaV controllers and I/O. This ensures that a loss of power to the DeltaV controller does not affect the operation of Logic Solvers, SISNet Repeaters, and SISNet Distance Extenders. In most installations, redundant 24 VDC power is used for both simplex and redundant SIS applications. When redundant 24 VDC power is used, both power supplies must be referenced to a common connection to ground.
CAUTION!Although the screw terminal connector on the Logic Solver, SISNet Repeater, and SISNet Distance Extender has two positive and two negative connectors, it is recommended that they not be used to daisy-chain power. Daisy-chaining could result in a loss of power to downstream Logic Solvers if power is removed or lost at an upstream Logic Solver.