Unlike single function devices, process calibrators are designed to offer the technician a one stop tool by covering a wide range of signal capabilities. Most are capable of measuring and simulating electrical and temperature based (RTD & T/C) signals. A good process calibrator will be rugged, with an alkaline or NiMH power system that will be able to drive into high loads for sustained periods. More advanced units feature options to add pressure modules or automated documenting features.