Dear Sir:

Maybe somebody can help me in understanding how to model a Modular Safety System 3RK3 in the Safety Evaluation Tools.

In my application, the MSS is composed by

- 1 basic unit,

- 1 expansion module 4/8-DI

- 1 expansion module 4/8-DO

On the input side, there are more E Push-buttons, or safety position switches, each one with 2 channels link. Some of these switches are connected to the Basic Module, others are connected to the expansion unit.

On the output side, there are couple of  channels each one driving a motor by two contactors.

So there are different  and independent STOP initiators for each of the two stop function.

Say there are 4 Stop initiators connected ad the basic unit,  each one stopping the motor A by the basic module outputs, and other 4 STOP initiators connected to the DI expansion, each one stopping the motor B by the outputs of the output expansion module.

My doubts is how to model this configuration on the Safety Evaluation Tool.

1) Must I create a safety function for each STOP initiator ?

2) Must I create two safety functions with the SRP as here below ?:

Function STOP MOTOR A

            DETECTION:

                        STOP initiator A1

                        STOP initiator A2

                        STOP initiator A3

                        STOP initiator A4

            EVALUATION:

                        MSS Basic Module

            REACTION:

                        Contactor A1

                        Contactor A2

Function STOP MOTOR B

            DETECTION:

                        STOP initiator B1

                        STOP initiator B2

                        STOP initiator B3

                        STOP initiator B4

            EVALUATION:

                        MSS Basic Module

                        MSS 4 F-DI

                        MSS 4 F-DO

            REACTION:

                        Contactor B1

                        Contactor B2

I hope you can suggest how to model this case.

Best regards