Bourdon Haenni has introduced the TED50, a programmable digital pressure switch, made of stainless steel, for controlling pressures in industrial processes. Accurate to +/–0.5% at 20°C, it is able to measure absolute pressure in the ranges 0 to 1 bar and 0 to 40 bar, or relative pressure and vacuum in the ranges –1 to 0 bar and 0 to 400 bar. With its built-in microprocessor, the TED50 can be configured in situ using the integral, sealed keypad to provide five different operating functions: Triggering point at two independent thresholds; hysteresis value of each adjustable threshold; threshold active state for alarm configuration; zero setting; parameter self-test and protection of settings with a four digit code. The breaking capacity of the micro-switches is 400mA without polarity at 60V DC or 40V AC, and optional 4-20mA analogue and RS 485 digital outputs enable the switch to operate in a variety of modes. A clear four-digit LED display also gives a visual indication of the fluid pressure. Current trials include Modbus protocol, with Profibus PA and other industry standard protocols planned for the future. The TED50 can operate on an unregulated power supply of between 18 and 24V DC, and it is protected against polarity reversal. Power consumption is 20mA at 24 V. Voltage free CMOS contacts are used, rather than the pnp contacts found on some other pressure switches. The TED50 is CE-marked and meets European standards for electromagnetic compatibility in terms of immunity and emissions.
