Steve Hoover, Ontario Canada
I use a Fluke 744 Process Calibrator for bench testing devices, using the internal 24 Volt D.C power supply. The Fluke 744 eliminates the need for 120 V AC and a rectified step down transformer (24 V DC). It's especially handy when elevated and installing 4-20 transmitters in HVAC ducts (pitot tube differential pressure transducers). The 744 is also an excellent tool for calibrating Smart transmitters using Hart protocol, since the transmitters can be powered and calibrated with one instrument.