SRE + is a PLC-control system with touch display for the negative pressure units.
Optionally, the negative pressure or the volume flow can be measured and controlled.
The negative pressure is measured between the contaminated area and a reference point to be defined and is kept at the set point by continuous speed control of the electric fan.

Manual operation
In manual operation, the "+" and "-" keys are used to set the fan power.
The display shows the performance value in %, the measured negative pressure in Pa, the volume flow in m³/h and cfm, and the absolute pressure in Pa after the filters.

Automatic operation
In the automatic operation negative pressure, the set point in Pascal for the negative pressure is set with the "+" and "-" keys.
The "+" and "-" keys are used to set the set point in m³/h and cfm for the volume flow.
By comparing the entered set value with the permanently measured current actual value, the speed of the fan is automatically adapted meaning the fan runs automatically "up" or "down".
The display shows the performance value in %, the measured negative pressure in Pa, the volume flow in m³/h and cfm, and the absolute pressure in Pa after the filters.
A filter sensor monitors the particle concentration in the exhaust air and triggers an optical and acoustic alarm if a value of ca. 100 particles per liter is permanently exceeded.
A necessary filter change is indicated on the display.