The LSDVTR function block provides a discrete voter function for safety instrumented functions. A voter block monitors a number of input values and determines if there are enough votes to trip. The LSDVTR block monitors as many as 16 discrete inputs. If a configured number of the inputs vote to trip, the block trips and sets the output of the block to 0 (zero).
For example, a process shutdown might be required if a tank exceeds a certain temperature. Three temperature sensors are installed in the tank and a discrete voter block is configured to monitor the sensors and trip if two of the three transmitters detect a high temperature.
The LSDVTR block does not support modes.
Because the Logic Solver is a De-energized to Trip environment the normal operating value of the output is 1 (On) and the tripped value is 0 (Off).
The following diagram shows the internal components of the LSDVTR function block.
