Siemens 3RS10421GD70

The Siemens product 3RS10421GD70 is a temperature monitoring relay designed for use with sensors such as PT100, PT1000, and KTY83/84, as well as NTC types. It features two digitally adjustable threshold settings, allowing monitoring within a wide temperature range from -50 °C up to 750 °C, depending on the sensor used. The device operates on a 24 V AC/DC power supply and includes two changeover contacts plus one normally open contact for flexible integration. Its compact 45 mm width and screw terminal connections make it straightforward to install in control panels. While this particular model has been phased out, it remains available through BSP Automation, who can also assist with suitable replacement options.