The UDC3500 has up to three universal analog inputs with a typical accuracy of ±0.10% of full-scale input and a typical resolution of 16 bits. These can easily be configured to operate as 2 universal and 2 high level or as 1 universal and 4 high level inputs. All analog inputs are sampled six times per second (every 166 milliseconds). The first, or process variable input, can be one of various thermocouple, RTD, radiamatic or linear actuations. Linear actuations have thermocouple, RTD and radiamatic transmitter characterization capability as a standard feature. Linear actuations also have square root capability. The optional second and third inputs are isolated from each other and all other circuits and accept the same actuations as input one. These optional inputs can each be split into two high level inputs. The fourth input is enabled by first configuring input 2 as a 20 mA or 5 Vdc input type (HLAI). Input 5 is then available as a high level input.