The 5440 Series Direct Voltage Calibrators are programmable or stand-alone dc voltage calibrators with an output voltage range of -1100V dc to 4T100V dc and uncertainty of three to four parts per million (referred to national standards). Designed for use in production environments as well as in calibration laboratories, the 5440 Series Calibrators operate without degradation of uncertainty specifications over a temperature range of ±5°C from the calibration temperature. The 5440 Series can accurately calibrate meters of up to 7-1/2 digits. The 5440 Series are convenient to operate. The front panel is tilted to make data entry- easy. and the two vacuum fluorescent displays are easy to read. A numeric Output Display shows the output value; a separate, 40-character. Alphanumeric Display indicates the operating mode, displays menus of operating features, prompts for entries, and shows other instrument messages. The 5440 Series are equipped with features that simplify operation. Special features include: • You can preset output voltage and current limits, and can preset tolerance limits for the unit under test. • An automatic Internal Calibration procedure corrects for drift in internal offsets and resistor ratios. • A display-prompted, semi-automatic External Calibration procedure corrects for long-term reference drift. • Output voltage and current levels are automatically monitored. • Output settings can be entered directly with the keyboard and can be incremented and decremented with convenient front panel controls. e Automatic self-tests check the Calibrator’s status and diagnose internal faults. • The IEEE-488 bus address and RS-232-C baud rate can be set from the front panel keyboard.