Reading Diagnostic Signals of Safety-related Modules

General Information

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

Beside the Safety Logic Controller exchange variables (see section Exchanging Data between Logic/Motion Controller and Safety Logic Controller), also the TM5/TM7 I/O modules provide diagnostic exchange signals.

After you have inserted a safety-related I/O module into your bus architecture (Devices tree in Logic Builder), and then confirmed the modified bus configuration in Machine Expert - Safety, these diagnostic signals are available in the Devices window.

NOTE: These signals are diagnostic signals for evaluation purposes in the standard application. They have no impact on the safety function. Diagnostic exchange signals always have a standard data type.
 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 the Physical State of a Safety-related Output Channel

This chapter describes the use of a diagnostic signal of a safety-related TM5/TM7 I/O module based on an application example: A safety-related TM5 output module provides one diagnostic signal per channel which mirrors the physical state of the safety-related output. These signals can be read in the standard Logic/Motion Controller application.

The following procedure describes how to map this signal in the standard application thus enabling the Logic/Motion Controller to react on the physical state of the safety-related output channel.

Procedure in EcoStruxure Machine Expert Logic Builder:

Step

Action

1

In the Devices tree, double-click the safety-related output module of which you want to read the output channel status.

2

Open the TM5 Module I/O Mapping editor.

3

In the signal table, locate the signal PhysicalStateChannelxx, where xx is the channel number. This signal is in the Status signal group.

4

Map a variable.

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.

5

Program a read access to the mapped variable in your application code (flag evaluation) and evaluate the variable in a way that the standard application can react on an undesired or unintended output channel status.