Description
This function block set is used to control the start and stop of an on-off humidifier. If the current humidity is below the subtraction of start/stop differential from the setpoint, the humidifier turns on; if it is above the sum of the start/stop differential and the setpoint, the humidifier turns off.
The humidifier is required to be switched off immediately in the event of a fault alarm.
Function
When "Fan Command" is "1" (0-OFF/1-ON) and "Humidity Input" is lower than the subtraction of start/stop differential from the setpoint, "Humidifier Command" is "1".
When "Fan Command" is "1" (0-OFF/1-ON) and "Humidity Input" is greater than the sum of the start/stop differential and the setpoint, "Humidifier Command" is "0".
When "Fan Command" is "0" (0-OFF/1-ON) or "Sensor Fault Alarm" is "1" (0-OK/1-FLT), "Humidifier Command" is "0".
Internal logic
Input
PIN | Data type | Unit | Default value | Value/range |
---|---|---|---|---|
FAN_CMD | BOOL | - | 0 | 0-OFF / 1-ON |
FAULT | BOOL | - | 0 | 0-OK / 1-FLT |
HUM_PV | FLOAT | % | 0 | 0...100 % |
HUM_SP | FLOAT | % | 50 | 0...100 % |
HYS | FLOAT | % | 6 | 0...100 % |
Output
PIN | Data type | Unit | Default value | Value/range |
---|---|---|---|---|
HUM_CMD | BOOL | - | - | 0-OFF / 1-ON |
Example