FB_BA_AntiBlocking
![FB_BA_AntiBlocking 1:](Images/png/12304290571__Web.png)
The template prevents blocking of pumps or actuators after prolonged idle periods by issuing a switch-on pulse.
A pulse output generally only occurs if the function block FB_BA_AntBlkg is enabled at bEn.
The maximum idle period before such a pulse is issued is determined by the value of the variable nOffMin. For logging the idle time, the input bFdb must be linked to the operating feedback from the aggregate. The length of the pulse is parameterized with the variable nImplLngt. For this function the operation mode E_BA_AntBlkgMode.eOffTime must be set (see E_BA_AntBlkgMode).
The input bExtReq should be used if the anti-blocking protection pulse is to be issued cyclically based on a schedule, rather than depending on the idle times. A rising edge at bExtReq immediately triggers output of a pulse to bQ. For this function the operation mode E_BA_AntBlkgMode.eExternalRequest must be set (see E_BA_AntBlkgMode).
![]() | The initialization of the template takes place within the method FB_Init. |
Block diagram
![FB_BA_AntiBlocking 3:](Images/png/14415499531__Web.png)
Syntax
FUNCTION_BLOCK FB_BA_AntBlkg EXTENDS FB_BA_View
VAR_INPUT
bFdb : BOOL;
bExtReq : BOOL;
bLock : BOOL;
END_VAR
VAR_OUTPUT
bQ : BOOL;
END_VAR
VAR_INPUT CONSTANT
IdlePrd : FB_BA_AV_Op;
ImpulseLength : FB_BA_AV_Op;
END_VAR
VAR_INPUT CONSTANT PERSISTENT
{attribute 'parameterCategory':='Operation'}
bEn : BOOL := TRUE;
END_VAR
VAR
AblkFnct : FB_BA_AntBlkg;
tonEn : TON;
END_VAR
Inputs
Name | Type | Description |
---|---|---|
bFdb | BOOL | Input for connecting the feedback signal of a motor or valve. This input is only considered in the operation mode E_BA_AntBlkgMode.eOffTime. |
bExtReq | BOOL | Active in the E_BA_AntBlkgMode.eExternalRequest operation mode. External request for a pulse, for example from a schedule. With a rising edge the anti-blocking protection pulse is started. |
bLock | BOOL | Active in the operation modes E_BA_AntBlkgMode.eExternalRequest or E_BA_AntBlkgMode.eOffTime. To prevent that e.g. the pump and the valve of a heater get a pulse at the same time, the output of the pulse is always suppressed until bLock is FALSE again. If bLock becomes TRUE during the output of an anti-blocking protection pulse, then the anti-blocking protection pulse is interrupted. After bLock is FALSE again, the anti-lock protection pulse is restarted. |
Inputs CONSTANT
Name | Type | Description |
---|---|---|
IdlePrd | AV object for input of the maximum pump standstill duration until an anti-blocking protection pulse is issued. | |
ImpulseLength | A rising edge at this input switches the output value fOut to the input value fIn. |
Inputs CONSTANT PERSISTENT
Name | Type | Description |
---|---|---|
bEn | BOOL | General enable of the template. If bEn is FALSE, the message output bQ is also FALSE. |
Variables
Name | Type | Description |
---|---|---|
bAblkFnct | The function block AblkFnct for the output of an anti-blocking protection pulse is the core of this template. | |
tonEn | TON | Start-up delay of the function after the controller has started up. |
Requirements
Development environment | Necessary function |
---|---|
TwinCAT from v3.1.4024.35 | TF8040 | TwinCAT Building Automation from V5.0.0.0 |