This device is a single channel, galvanically isolated intrinsic safety barrier that transfers discrete signals (NAMUR sensors/mechanical contacts) from a hazardous area to a safe area. The proximity sensor or switch controls a form C relay contact for the safe area load. The barrier output changes state when the input signal changes state.The normal output state can be reversed through the mode of operation switch S1. For a mechanical contact, LB monitoring can be selected by placing a 10 k7 resistor across the mechanical contact in the field and moving switch S3 to position I on the barrier. SC monitoring is added by placing a 4007-2 k7 resistor in series with the mechanical contact. NAMUR proximity sensors, however, are designed with the LB and SC functions, making external resistors unnecessary. In case of a LB/SC fault, the signal output relay reverts to thedeenergized state. LB/SC monitoring can be disabled with S3 in position II. If used in conjunction with P+F's Power Rail system, the unique collective error messaging feature can be utilized.
