Loop and Frequency CalibratorsDPI 832 electrical loop calibrator and DPI 841/842 frequency calibrator include common features such as large, bright, backlit displays for easy reading in all lighting conditions, rubberized exteriors for durability and ruggedness, intuitive menu systems for ease of use, and HART loop resistors. The new DPI 832/841/842 models also include an intelligent digital output sensors port, allowing remote pressure module connectivity from 10 inH2O to 3000 psi.