FB_BA_FdbCtrlBinary

The function block FB_BA_FdbCtrlBinary is used for feedback monitoring of an actuator by means of digital feedback. Application examples of the function block are, for example, an operation feedback monitoring, a process feedback monitoring or the run monitoring of a drive by means of limit switches.

The function block monitors a limit switch in two steps, for example. Step 1 includes monitoring while the actuator is moving. Step 2 includes monitoring of the opened state of the actuator.

Step 1: If a TRUE is present at the input bActuator, then the travel time of the actuator nFdbDelay/nRemTiFdbDelay expires. If no TRUE is present at input bSwitch within this time, this is indicated via output bQ. If bSwitch becomes TRUE within the time nFdbDelay, step 1 is complete and step 2 becomes active.

Step 2: bActuator and bSwitch are TRUE. If bActuator becomes FALSE, step 1 becomes active again. If bSwitch becomes FALSE and within the time nInterruptionDelay/nRemTiInterruptionDelay is not TRUE again, this is indicated via the output bQ.

In addition, the idle position of the actuator is monitored. That is, if bActuator is not active and the feedback signal bSwitch indicates a TRUE, then after the time nFdbDelay has elapsed, the output bQ is set to TRUE.

bQ signals that the monitoring of the feedback signal has a fault.

Inputs

VAR_INPUT
  bEn                      : BOOL;
  bActuator                : BOOL;
  bSwitch                  : BOOL;
  nFdbDelay                : UDINT;
  nInterruptionDelay       : UDINT;
END_VAR

Name	Type	Description
bEn	BOOL	General enable of the function block. If bEn is FALSE, the message output bQ is also FALSE.
bActuator	BOOL	The switching actuator output of the aggregate to be monitored is connected to this input.
bSwitch	BOOL	Used to connect the feedback signal, e.g. of a differential pressure switch, flow monitor or limit switch.
nFdbDelay	UDINT	Response delay [s] of the monitoring function when the actuator is started. The input of the time is limited to the global parameter BAComn_Global.udiMaxSecInMilli from the Tc3_BA2_Common library (see BAComn_Global).
nInterruptionDelay	UDINT	Delay time (e.g. of a limit switch) in the open state in [s]. The input of the time is limited to the global parameter BAComn_Global.udiMaxSecInMilli from the Tc3_BA2_Common library, see (BAComn_Global).

Outputs

VAR_OUTPUT
  bQ                       : BOOL;
  nRemTiFdbDelay           : UDINT;
  nRemTiInterruptionDelay  : UDINT;
END_VAR

Name	Type	Description
bQ	BOOL	bQ is used to signal that the monitoring of the feedback signal indicates a fault.
nRemTiFdbDelay	UDINT	Remaining time [s] until output bQ is set. The default comes from nFdbDelay.
nRemTiInterruptionDelay	UDINT	Remaining time [s] until output bQ is set. The default comes from nInterruptionDelay.

Requirements

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