Cascade Control Of Reflow Ovens; Application - Omron E5AR - MANUAL 2 User Manual

3.4 Cascade control of reflow ovens

Cascade control is used to reduce the effects of disturbances in the manipulated system (disturbances in
the secondary loop) by adding a second PID loop to the regular PID loop.
Cascade control is also used in situations where a sensor is added close to the object to improve control
performance.

■ Application

Conventional temperature control of reflow ovens is performed using
only a sensor installed near the heater. In lead-free reflow ovens, the
melting temperature of solder is higher, and in order to minimize heat-
induced deterioration of the electronic components, a second sensor is
added inside the oven near the board to enable a higher precision of
temperature control.
E5AR
G3PX
Power controller
Work
Heater
Temperature sensor
• A thermocouple or platinum resistance temperature
input sensor can also be directly connected to input 2
Hint
(previously input 2 only supported 4 to 20 mA or 1 to 5
V, and an external converter was required).
• Auto tuning is now possible in both the cascade closed
and cascade open states.

3.4 Cascade control of reflow ovens

E5AR E5AR
G3PX G3PX
Power controller Power controller
N2 atmosphere
Conveyor
3-13