FAN_VFD Fan Variable Frequency Drive Control - Operation Manual - ELC.E14 - EM1.8D - EM1.8R - EM1.8U

Description

This function block set uses PID to adjust fan variable frequency according to the setpoint and current values such air pressure and CO2.

Of all the inputs, Fault Alarm is generated from a PID-adjustable primary sensor. Once there is such an alarm, the PID-calculated output is 0 %.

This set also has a manually override function. If "Fan Variable Frequency Drive Mode Select" is "0 - MAN (manual)", the output is "Fan Variable Frequency Drive Manual Setpoint". If "Fan Variable Frequency Drive Mode Select" is "1 - AUTO", the output is the automatic logic value of the application.

Note: PID control of CO2 is direct-proportional and that of air pressure is inverse-proportional.

Function

When "Fan Command" is "1" (0-OFF/1-ON) and "Sensor Fault Alarm" is "0" (0-OK/1-FLT), "Fan Variable Drive Control", based on PI calculation, outputs a frequency value that is equal to half of the PI output and between 0 and 50 Hz. The frequency value should also be limited between "Min. Output" and "Max. Output".

At any time when "Fan Variable Frequency Drive Mode Select" is "0" (0-MAN/1-AUTO), "Fan Variable Drive Control" is "Fan Variable Frequency Drive Manual Setpoint".

When "Fan Command" is "0" (0-OFF/1-ON) or "Sensor Fault Alarm" is "1" (0-OK/1-FLT), "Fan Variable Drive Control" is 0 Hz.

Note: PID control of CO2 is direct-proportional and that of air pressure is inverse-proportional.

The output priority is: Manual mode > Sensor Fault Alarm > PID calculated output in automatic mode.

Internal logic

Input

Output

Example