Safety Considerations Guide for Triconex General ... - ICEWeb

24 Chapter 2 Application Guidelines
6 Print all logic elements and verify that the changes to networks within each element do
not affect other sections of the application.
7 Test the changes according to the test specification using the Emulator Panel. For details,
see the TriStation 1131 Developer’s Guide.
8 Write a test report.
9 Review and audit all changes and test results with the SCCC.
10 When approved by the SCCC, download the changes to the controller.
• You may make minor changes online only if the changes are absolutely necessary
and are tested thoroughly.
• To enable a Download Change command, select the Enable Programming and
Control option in the Set Programming Mode dialog box on the Controller Panel if
it is not already selected.
Note
Changing the operating mode to PROGRAM generates an alarm to remind the operator
to return the operating mode to RUN as soon as possible after the Download Change.
For more information, see Programming Permitted Alarm on page 59.
11 Save the downloaded project in the TriStation 1131 software and back up the project.
12 Archive two copies of the project file and all associated documentation.
Maintenance Overrides
Three methods can be used to check safety-critical devices connected to controllers:
• Special switches are connected to the inputs on a controller. These inputs deactivate the
actuators and sensors undergoing maintenance. The maintenance condition is handled
in the logic of the control application.
• Sensors and actuators are electrically disconnected from a controller and manually
checked using special measures.
• Communication to a controller activates the maintenance override condition. This
method is useful when space is limited; the maintenance console should be integrated
with the operator display.
TÜV recommends that the TriStation 1131 workstation used for programming is not also used
for maintenance.
Using Triconex Communication Capabilities
For maintenance overrides, two options for connection are available:
• DCS (distributed control system) connection using an approved protocol.
• TriStation 1131 PC connection, which requires additional, industry-standard safety
measures in a controller to prevent downloading a program change during
maintenance intervals. For more information, see Alarm Usage on page 59.
Safety Considerations Guide for Triconex General Purpose v2 Systems