The MINIMUX® II PD138 is a microprocessor-based, eight-channel analog input scanner/multiplexer and annunciator that provides low-cost automatic switching for multi-point display and alarm systems. It can automatically switch up to eight inputs to another device such as a digital panel meter, controller, or PLC. Signal switching is done via reed relays making the PD138 ideal for switching thermocouples, RTDs, control loops, and AC/DC signals. They feature rugged NEMA 4X/IP65 fronts and a wide operating temperature range. They can be programmed for many common ISA alarm sequences including first out indication and they provide alarm signaling through front panel LEDs and a build in 85 dB horn.