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

ControlLogix I/O Modules 6-9The control, diagnostics and alarming functions must beperformed in sequence. For more information on faults, seeChapter 7, Faults in the ControlLogix System.• Use of external Relays to disconnect Module Power ifOutput De-energization is Critical: To make sure outputs willde-energize, users must wire an external relay that can removepower from the output module if a short or other fault isdetected. See Figure 6.7 on page 6-10 for an example method ofwiring an external relay.• Test outputs at specific times to make sure they areoperating properly. The method and frequency of testing isdetermined by the type of module–diagnostic or standard. Formore information on testing diagnostic module outputs, seepage 6-10. For more information on testing standard moduleoutputs, see page 6-11.• For typical emergency shutdown (ESD) applicationsoutputs must be configured to De-energize: Whenconfiguring any ControlLogix output module, each output mustbe configured to de-energize in the event of a fault and in theevent of the controller going into program mode. For exceptionsto the typical ESD applications, see Chapter 1, SIL Policy.• When wiring two digital output modules in series so that onemay break source voltage (as shown in Figure 6.10 onpage 6-12), make sure:– Both modules use identical configuration.– The same controller owns both modules.Publication 1756-RM001B-EN-P - October 2003