The local sensors send their measurement signals (4–
20 mA signal) to a PLC, and then, they are recorded in a
PC. The frequencies at the motors are recorded too. The
thermocouples placed at the rotating shell of the dryer
transmit their measurements via radio-signal to the
PC, to avoid the difficult associated to the movement.
The wet temperature sensor is of our own design, somewhat
roughness but very reliable. The flow meter is provided
with a pneumatic cleaning system, but it needed
frequently manual cleaning because of the oil vapours.