Description of safety function block of the As-i bus

Description of the function

This DFB allows data processed by the security monitor to be obtained.

Representation in FBD

Representation of the security DFB:

Description of the parameters

The following table describes the input parameters:

Parameter	Type	Description
I0	EBOOL	Input variable 0: %I\b.e\r.m.0.
I1	EBOOL	Input variable 1: %I\b.e\r.m.1.
I2	EBOOL	Input variable 2: %I\b.e\r.m.2.
I3	EBOOL	Input variable 3: %I\b.e\r.m.3.

Legend:
b: AS-i bus number. e: slave number. r: rack. m: module.

The following table describes the input/output parameters:

Parameter	Type	Description
Enable	EBOOL	Activation of the DFB (Cold Start): if this bit is at "1", the DFB executes, otherwise it is deactivated. The information is only usable if Enable = 0.
Q0	EBOOL	Output variable 0: %Q\b.e\r.m.0.
Q1	EBOOL	Output variable 1: %Q\b.e\r.m.1.
Q2	EBOOL	Output variable 2: %Q\b.e\r.m.2.
Q3	EBOOL	Output variable 3: %Q\b.e\r.m.3.

Legend:
b: AS-i bus number. e: slave number. r: rack. m: module.

The following table describes the output parameters:

Parameter	Type	Description
Error	EBOOL	This bit is set at "1" if an error appears: DFB error or security bus error (at least one slave is faulty): if it is a DFB error (enable = 0): see Dfb_error (≠ 0) for more information. In the case of a DFB error, the information on the security project are no longer valid. it is a case of a security project error (Dfb_error = 0 and Enable = 1): see S1_ to find out the faulty slaves.
Running	EBOOL	This bit is set at "1" during execution of the DFB.

The following table describes the internal public variables:

Name	Type	Description
Abort	EBOOL	If this bit is at "0" in one cycle and at "1" in the next, all the changes between CPU and the security monitor are stopped and the DFB reinitializes. All the internal data of the DFB are set at 0.
Timeout	INT	Timeout of the data exchanges (time base of 100 ms). If the DFB does not receive a correction before this period, the transaction is cancelled, the DFB is deactivated and the error bit is set at "1" (Dfb_stat and Dfb_err are updated).
Moni_err	EBOOL	this bit is at "1" if the monitor is faulty.
Out_1	EBOOL	this bit is at "1" if the OUT1 contact is closed.
Out_2	EBOOL	this bit is at "1" if the OUT2 contact is closed.
SI_ready	DINT	each bit corresponds to the index of the security device that is in a test or read state.
SI_off	DINT	each bit corresponds to the index of the security device that is deactivated.
SI_error	DINT	each bit corresponds to the index of the security device that is faulty.
Dfb_stat	INT	this is the state of the DFB; this variable allows the user to check the progress of the DFB.
Dfb_err	INT	This word gives the error type: 16#90: the reply sent by the monitor is invalid, 16#91: the DFB has been deleted by the user, 16#92: the exchange has stopped on a Timeout, the DFB cannot receive data.

Searching for a security slave that has been activated

The search for the address of a security slave that has been activated can be facilitated by taking into account inputs I3/I2/I1/I0 of the slave. These inputs are equal to 0/0/0/0 if the slave is activated, and different from 0/0/0/0 if the slave is not activated. This information must not be taken into account in the security: only the security monitor provides security outputs.