AADvance Safety Manual - Tuv-fs.com

Chapter 5 AADvance Functional Safety SystemImplementationProcess safety time faultsFor a digital output module, the process safety time represents the period of awatchdog timer that specifies the length of time the controller will allow the module torun without receiving updates from the application. If the module runs beyond this timeperiod without receiving any updates, it enters the shut down state.Shutdown stateThe shut down state can be configured for the following settings: off de-energize (fail-safe) hold last stateYou have to decide when you configure the module how you want the output channelsto behave in the shutdown state, the default is fail-safe.Careful consideration should be given to the affect on the process of using the'hold last state' setting.Disable line testThe digital output module incorporates line test functionality that can report andindicate 'no load' field faults. This functionality can be enabled or disabled. The settingsare: Yes - disables reporting and indication of 'no load' field faults No - 'No load' field faults are reported and indicatedAvailability of output modulesOutput modules support redundancy when configured in dual operation using theappropriate termination assembly. One redundant module may be inserted or removedat any time without any impact on the safety function of the system.DO termination assemblyThe DO termination assembly is safety critical, it comes in two sizes — simplex ordual. It has fuses for field output power and 8 field termination connections for theoutput signals.Input and Output ForcingThe AADvance Workbench supports forcing of individual inputs and outputs. TheWorkbench uses the term 'locking' to describe forcing.Document number 553630 Issue 7: February 2010 5-23