MP_VAV
This function block is used to control and monitor a volume flow regulator.
MP_Address is used to specify the MP-Bus device with which the function block is to communicate. bStart activates communication with the MP-Bus device. bBusy indicates that the function block is active. If bStart remains TRUE, the device is addressed cyclically with a period specified by the time in TMPolling. The time should be set longer than 1 second. bError is used to indicate an error in communication with the drive. The type of the error can be read with iErrorID.
A rising edge at bReset clears any pending error messages from the drive. This resets errors that affect the output variables bErr_MecOcld, bErr_ActHunt and bErrMecTrv. If the error itself is still present, the drive will set these error bits again.
SetPoint is used to adjust the volume flow rate from 0..100%. The current position of the damper can be read through ActValue.
If a sensor is connected to the drive, iSensorTyp should be used to specify the sensor type. If no sensor is connected, the value "0" should be entered, or the variable should be left blank. A digital sensor should be parameterized with "1". The state of the sensor can be interrogated through bMP_Sensor_Digi. Analog sensors "2...6" are output in variable iMP_Sensor_Analog.
A rising edge at the bOpen or bClose inputs opens or closes the damper of the drive. A falling edge at these two inputs clears the command again.
MaxVol and MinVol can be used to store a maximum and minimum flow rate in the drive. A rising edge at bSet writes the data to the drive. You can obtain the current value from the output data act_MaxVol and act_MinVol. The current volume flow rate is output in the AirVolume_m3h variable.
Inputs
VAR_INPUT
MP_Address : USINT := 1;
bStart : BOOL;
bSet : BOOL;
bOpen : BOOL;
bClose : BOOL;
bReset : BOOL;
iSensorTyp : INT;
SetPoint : USINT;
MaxVol : WORD;
MinVol : WORD;
strDataKL6771 : DataKL6771;
TMpolling : TIME := t#10s;
END_VAR
Name | Type | Description |
|---|---|---|
MP_Address | USINT | MP-Bus address of the slave. |
bStart | BOOL | A positive edge starts the function block. If this remains continuously TRUE, the function block will be activated cyclically with a period specified by the time in TMPolling. |
bSet | BOOL | A positive edge writes the data MaxVol and MinVol to the actuator. |
bOpen | BOOL | A positive edge opens the dampers of the actuator, while a negative edge cancels the forced ventilation. |
bClose | BOOL | A positive edge closes the dampers of the actuator, while a negative edge cancels the forced closure. |
bReset | BOOL | A positive edge resets the actuator's error messages. |
iSensorTyp | INT | 0: no sensor connected, 1: digital sensor connected, 2: analog sensor connected (0...35 V), 3...6: output of a resistance in ohms (3..5 applies to PT1000, NI1000 and NI1000LuS; 6 applies to NTC). To convert to a temperature, use the corresponding conversion functions. |
SetPoint | USINT | 0…100 % set volume flow rate |
MaxVol | WORD | 30...100 % Maximum volume flow rate |
MinVol | WORD | 0…100 % Minimum volume flow rate |
strDataKL6771 | The data structure with which the KL6771() function block must be linked. | |
TMpolling | TIME | The time for which the function block should address the actuator. Default 10 s, minimum time 1 s. |
Outputs
VAR_OUTPUT
bBusy : BOOL;
bError : BOOL;
iErrorId : MP_Error;
ActValue : WORD;
bMP_Sensor_Digi : BOOL;
iMP_Sensor_Analog : INT;
AirVolume_m3h : WORD;
act_MaxVol : INT;
act_MinVol : INT;
bErr_ActHunt : BOOL;
bErr_MecTrv : BOOL;
bErr_MecOvld : BOOL;
END_VAR
Name | Type | Description |
|---|---|---|
bBusy | BOOL | This bit is set for as long as the function block is active. |
bError | BOOL | This output goes TRUE as soon as an error occurs. This error is described via the iErrorId variable. |
iErrorId | This output outputs an error code in the event of an error. bError goes TRUE at the same time. | |
ActValue | WORD | Contains the current position of the actuator (0...100 %). |
bMP_Sensor_Digi | BOOL | If a digital sensor is connected, its state is indicated through this variable. iSensorTyp must be "1". |
iMP_Sensor_Analog | INT | If an analog sensor is connected, its value is indicated through this variable. iSensorTyp must be "2...6". |
AirVolume_m3h | WORD | Output of the volume flow rate in m³/h. |
act_MaxVol | INT | Maximum set volume flow rate in %. |
act_MinVol | INT | Minimum set volume flow rate in %. |
bErr_ActHunt | BOOL | Actuator error, "Regulating oscillation"; the actuator is swinging backwards and forwards. |
bErr_MecTrv | BOOL | Actuator error, "Positioning angle exceeded"; the actuator has passed more than 10° beyond the adaptation position. |
bErr_MecOvld | BOOL | Actuator error, "Overload"; the set position could not be reached. |
Requirements
Development environment | required TC3 PLC library |
|---|---|
TwinCAT from v3.1.4020.14 | Tc2_MPBus from 3.3.5.0 |