Thermatel FCI 12-64 Sensor Design Active RTD Reference RTD Heater Constant wattage heater (5 watt, maybe even 10 watt depending upon application). Reference RTD measures process temperature. Active RTD measures temperature of heater. Sensors are 3/8" diameter by 1.5 " long (big thermal mass) Flow cools heater, detected by active RTD. Set point adjusts the delta Temp where the switch will trip. Note the large thermal mass which results in long response time. and the sensor will overheat if run dry. Reference RTD Heater

Thermatel FCI FLT 93 Sensor Design FLT-F FLT-S RTD RTD Heater Heater After Magnetrol introduced the TDF, FCI developed a twin pin sensor. One sensor has a heater and a RTD. The other sensor has a RTD. The operation is the same as the 12-64. However the FLT-93 now has smaller thermal mass, faster response time, and one sensor for any fluid. The FLT-S is a heavier duty sensor with greatr thermal mass. RTD RTD Heater Heater

Thermatel vs FCI Magnetrol Magnetrol FCI FCI TDF/TDL TSF/TSL 12-64 Basic FLT 93 Tiempo de respuesta (seg) 1 a 10 1 a 10 10 a 300 1 a 10 Diseño del sensor Twin tip Spherical tip Twin tip Spherical tip 3 high mass 2 medium mass Calentador (vatios) 0.5 max. 0.5 max. 5 a 10 0.6 a 3.0 Calentador Variable Variable Constante Constante Operación seco Si Si No Quizás Construcción del sensor 316 SS Welded 316 SS Welded 316 SS with nickel braze 316 SS Welded