FB_BA_AntBlkg

This function block FB_BA_AntBlkg prevents blocking of pumps or actuators after prolonged idle periods by issuing a switch-on pulse.
Generally, a pulse output only occurs if the function block at bEn is enabled.

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.

The input bExtReq should be used if the 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.

Inputs

VAR_INPUT
  bEn               : BOOL;
  bFdb              : BOOL;
  bExtReq           : BOOL;
  bLock             : BOOL;
  nOffMin           : UDINT;
  nImplLngt         : UDINT;
END_VAR

Name	Type	Description
bEn	BOOL	bEn is the general enable of the function block. If bEn is FALSE, the message output bQ is also FALSE.
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 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 a blocking protection pulse, then the blocking protection pulse is interrupted. After bLock is FALSE again, the blocking protection pulse is restarted.
nOffMin	UDINT	Minimum switch-off time of the actuator without movement of the motor or valve [s].
nImplLngt	UDINT	Length of the blocking protection pulse [s] at bQ.

Inputs CONSTANT PERSISTENT

VAR_INPUT CONSTANT PERSISTENT
  eMode    : E_BA_AntBlkgMode := E_BA_AntBlkgMode.eOffTime;
END_VAR

Name	Type	Description
eMode	E_BA_AntBlkgMode	Input that specifies the operation mode of the function block

E_BA_AntBlkgMode.eOff - the operation mode eOff is similar to the input bEn. If this operation mode is active, the pulse output bQ is FALSE.

E_BA_AntBlkgMode.eExternalRequest - External request for a pulse, for example from a schedule. With a rising edge the blocking protection pulse is started.

E_BA_AntBlkgMode.eOffTime - Minimum switch-off time of the actuator without movement of the motor or valve (bFdb = FALSE). After the timer has expired, the blocking protection pulse is started.

Outputs

VAR_OUTPUT
  bQ                 : BOOL;
  nRemOffMin         : UDINT;
  nRemImplLngt       : UDINT;
END_VAR

Name	Type	Description
bQ	BOOL	Output for the blocking protection pulse.
nRemOffMin	UDINT	Remaining time [s] before the next pulse is issued in the absence of movement.
nRemImplLngt	UDINT	Remaining residual time [s] of the pulse at bQ.

Requirements

Development environment	Required PLC library
TwinCAT from v3.1.4024.22	Tc3_BA2 from v5.2.5.0