Microprocessor-based Model TB82PH monitors its own circuitry and that of attached pH/ORP sensor, sold separately. User reads diagnostic data on front-panel display or handheld communicator. Multifunction keys speed configuration and interrogation. Transmitter shares data with HART-based communication device, PC, or DCS. Mounting in panel or field, it has two security levels, adjustable damping, and hold output to simplify calibration.