Description
This function block set is used to monitor if there is fan differential pressure before and after a fan switches on. If no, an alarm is generated to inform maintenance personnel of further inspection. A broken fan belt, for example, may cause such alarm to occur.
Function
The function block set starts timing when "Fan Command" is "1" (0-OFF/1-ON) and outputs "Fan Differential Pressure Alarm" as "1" if "Fan Differential Pressure Status" is detected as "0-OPN" after the counted time exceeds "Differential Pressure Time Delay". It doesn’t generate an alarm if the differential pressure status is "1-CLS".
Internal logic
Input
PIN | Data type | Unit | Default value | Value/range |
|---|---|---|---|---|
FAN_CMD | BOOL | - | 0 | 0-OFF / 1-ON |
FAN_DPS | BOOL | - | 0 | 0-OPEN / 1-CLOSE |
TIME_DELAY | FLOAT | s | 30 | 0...65535 |
Output
PIN | Data type | Unit | Default value | Value/range |
|---|---|---|---|---|
FAN_DP_ALM | BOOL | - | - | 0-OFF / 1-ON |
Example
