1756-RM001B-EN-P, Using ControlLogix in SIL2 ... - Tuv-fs.com

6-4 ControlLogix I/O ModulesModule Fault Reporting forany ControlLogix I/OModuleUsers must make sure that all ControlLogix I/O modules are operatingproperly in the system. If the modules are not operating properly, theuser must initiate a fault routine when a fault occurs. This can beaccomplished in ladder logic through the use of the Get System Valueinstruction (GSV) and an examination of the MODULE object’s ’EntryStatus’ attribute for a running condition.An example of how this might be done is shown in Figure 6.2. Thismethod, or something similar, must be used to interrogate the healthof each I/O module in the system.Figure 6.2 Example of Checking a Module’s Health in Ladder LogicGSVObtain MODULEObject’s Entry StatusANDMask Off Lower 12Bits of ValueNEQCheck Entry Status tomake sure module isrunningFaultFor more information on the GSV instruction and MODULE Objects,see Chapter 7, Faults in the ControlLogix System. For moreinformation on creating Fault Routines, see Appendix B, SystemSelf-Testing and User-Programmed Responses.Using DigitalInput ModulesControlLogix digital input modules are divided into two categories:• Diagnostic input modules• Standard input modulesThese modules share many of the same inherent architecturalcharacteristics. However, the diagnostic input modules incorporatefeatures that allow diagnosing of field-side failures. These featuresinclude broken wire (that is, wire-off) detection and, in the case of ACDiagnostic modules, loss of line power.Publication 1756-RM001B-EN-P - October 2003