DeltaV SISTM Logic Solver

Local Peer Bus (SISnet):

Logic Solvers communicate with other Logic Solvers and with local SISnet Repeaters through the carriers over a 2 channel local peer bus. The same message is broadcast over both channels. The local peer bus must be terminated at both ends. The local peer bus is terminated at the left end through the 2-wide power/controller carrier and at the right end through a terminated 1-wide carrier.

The SISnet Repeaters can be located anywhere on a local peer bus – between the DeltaV Controller(s) and the terminated 1-wide carrier

Remote Peer Ring

: SISnet Repeaters hosted by one DeltaV controller communicate with SISnet Repeaters hosted by a different DeltaV controller over a fiber-optic remote peer ring. A local SISnet Repeater collects locally generated messages that have been designated as global variables into a single message and sends it to the next SISnet Repeater in the ring. Upon receipt of a message, the receiving SISnet Repeater broadcasts it on its local peer bus (SISnet) and forwards the message to the next SISnet Repeater in the ring. A global message is forwarded around the ring once. The primary SISnet Repeaters form one fiber-optic ring and the secondary form a separate, independent ring.

Carrier extender cables and local peer bus extender cables connecting a DeltaV controller and 8-wide carrier with standard DeltaV I/O and DeltaV SIS Logic Solvers to a second 8-wide carrier (hosted by the same controller) are installed with Logic Solvers, SISnet Repeaters, and a terminated 1-wide carrier. Logic Solver messages are communicated to a remote DeltaV SIS (hosted by a separate controller) through fiber-optic cables.

Line Fault Detection — The Discrete Input channels have line fault detection for detecting open or short circuits in field wiring. To use this capability you must:  Enable line fault detection in your configuration. Enable line fault detection on a channel-by-channel basis when you configure the channels.  Connect the dry contact to external resistors. Connect the dry contact to a 12 KΩ resistor in parallel (allows the open circuit detection) and a 2.4 KΩ resistor in series (allows short circuit detection). Line Fault Detection in NAMUR Sensors — Line fault detection is built into NAMUR sensors. Do not use external resistors with NAMUR sensors; however, you must enable line fault detection in your configuration when using NAMUR sensors.