Exchanging Data Between Logic/Motion Controller and Safety Logic Controller

General Information

The standard application (Logic/Motion Controller) and the safety-related application can directly exchange data.

When inserting an Safety Logic Controller into the Logic/Motion Controller project in EcoStruxure Machine Expert Logic Builder, a special memory area for exchange data is reserved. In this area, exchange signals are available. Which exchange data are to be used in your project must be configured in the I/O configuration of the Safety Logic Controller. Refer to the chapter Exchange Data Configuration for the SLC for details, limitations, and a step-by-step procedure.

NOTE: Exchange data between the standard and the safety-related application are always non-safety-related (standard) variables.
NOTE: In addition to the exchange signals of the Safety Logic Controller, also the TM5/TM7 I/O modules provide exchange signals. To map these signals in Logic Builder, double-click the respective TM5/TM7 module in the Devices tree and open the editor TM5/TM7 Module I/O Mapping. Refer to the section Reading the Status of Safety-related Output Channels for an example.
 WARNING
UNINTENDED EQUIPMENT OPERATION
  • Verify that the relevant diagnostic process data items provided by the Safety Logic Controller and the I/O modules involved in your safety-related application are monitored and evaluated so that your standard application can determine the state of the functional safety-related system.
  • Validate that the machine is set to the application-specific defined safe state (according to your risk analysis) depending on the safety-related diagnostic process data evaluation.
  • Use appropriate safety interlocks where personnel and/or equipment hazards exist.
  • Validate the overall safety-related function and thoroughly test the application.
Failure to follow these instructions can result in death, serious injury, or equipment damage.

Reading an SLC Exchange Variable in the Logic/Motion Controller

This chapter describes the possible use of an exchange variable with the data direction Safety Logic Controller to Logic/Motion Controller based on the following example:

A safety-related SF_EmergencyStop function block used in the safety-related application outputs a Boolean error flag.

The following procedures describe how to set up and configure the data exchange and read this value in the standard application thus enabling the Logic/Motion Controller to react on a function block error.

Procedure in EcoStruxure Machine Expert Logic Builder:

Step

Action

1

In the parameter group SlcIoConfiguration of the Safety_PLC (Devics tree), reserve one Boolean variable group SLC2LMC_NumberOfBoolGroups as described in section Configuring the Data Exchange.

Result: Eight Boolean exchange variables are available in the safety-related application.

2

Open the Schneider Electric Sercos III I/O Mapping editor of the Safety_PLC and map a variable to the exchange flag.

You have two possibilities:

  • Enter a variable name into the Variable table cell. This way, a new global variable is declared if the entered name is not yet declared.

  • Or double-click the … icon to select an existing variable from the Input Assistant.

3

Program a read access to the mapped variable in your application code (flag evaluation). Evaluate the variable in a way that the standard application reacts on a function block error, that is, if the variable is TRUE.

Procedure in Machine Expert - Safety:

Step

Action

1

Open the code worksheet where you want to insert and write the exchange signal. In the example, this is the code where the SF_EmergencyStop function block is used.

2

In the Devices window, open the devices tree on the left and expand the SLC (SL1.SM1) tree node.

3

Drag the Boolxxx exchange variable into the code worksheet.

Result: When releasing the mouse button, the Variable dialog appears.

4

In the Variable dialog, accept the proposed name, select an existing global variable, or declare a new global variable.

5

Confirm the Variable dialog by clicking OK and drop the variable at the desired position with a left click.

Result: The variable is inserted into the code and its variable declaration is automatically inserted into the global variable worksheet.

You can directly connect the variable to another object (for example, a formal parameter) or drop it unconnected at any free position.