Patent ID: 7512521

Claim:
A hand held configurator for coupling to a two wire process control loop for use in configuring and monitoring field units coupled to the two wire process control loop, comprising: loop coupling circuitry configured to couple to the two wire process control loop; a first power island having a first maximum allowed power draw based upon a maximum allowed surface temperature of a first component under a fault condition; a second power island having a second maximum allowed power draw based upon a maximum allowed surface temperature of a second component under a fault condition; a power supply configured to provide total power to the power islands which is greater than a sum of the first maximum allowed power and the second maximum allowed power; and barrier circuitry coupled to the first and second power islands configured to limit power entering the first power island to a value less than the first maximum allowed power draw and further configured limit power entering the second power island to a value less than the second maximum allowed power draw to thereby maintain intrinsic safety of the first and second power islands.