Safety Considerations Guide for Triconex General ... - ICEWeb

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38 Chapter 3 Fault Management Digital Output Module Alarms Digital output module faults are reported to the control application and can be used to increase availability during specific multiple-fault conditions. Loss of field power or logic power is reported to the control application. The inability of a digital output module to control an output point is reported to the control application as a Load/Fuse alarm. This condition can result from a loss of field power or a field short condition. The alarm can be used to modify the control strategy or direct effective maintenance action. Pulse Input (PI) Module The pulse input module points use a combination of comparison and reference diagnostics. Under system control, each channel is independently compared against the measured value of all channels. If a mismatch is found, an alarm is set. Each channel’s measured values are also compared against the channel’s internal references. These diagnostics are executed independently by each channel, thus assuring nearly 100 percent fault coverage and fail-safe operation under all single-fault scenarios, and most common multiple-fault scenarios. Pulse Input Module Alarms Pulse input module faults are reported to the control application. These alarms can be used to increase availability during specific multiple-fault conditions. Loss of logic power is reported to the control application. Solid-State Relay Output (SRO) Modules Solid-state relay output module points are not intended for safety-critical applications. The diagnostics used by the solid-state relay output points cannot detect faults in the relay contacts. Solid-State Relay Output Module Alarms Solid-state relay output module faults are reported to the control application. Safety Considerations Guide for Triconex General Purpose v2 Systems
Module Diagnostics 39 Calculation for Diagnostic Fault Reporting Time Typical and worst-case fault reporting times can be determined by using the formula in this section. For typical configurations with less than eight AI modules, the calculation is not required and the default values can be used. The default values are: • 500 milliseconds for a typical case • 725 milliseconds for a worst case For configurations with more than eight AI modules, the formula allows you to calculate typical and worst-case fault reporting times. This table provides a sample calculation. Table 5 Module Type Procedure Calculating Diagnostic Fault Reporting Time Example Number in System Multiplier Result AI 10 16 160 DI 2 1 2 PI 0 6 0 AO 0 5 0 DO 2 1 2 SRO 0 1 0 164 x 1.2 = 196.8 Typical Case: 196.8 x 3 = 590.4 milliseconds + 1/2 scan time Worst Case: 196.8 x 4.5 = 885.6 milliseconds + 1 scan time 1 Enter the number of modules and multiply each by the multiplier for the module type and then add the results. 2 Multiply the result of step 1 by 1.2. 3 If the result for step 2 is greater than 150, use the greater number; otherwise, use 150. 4 To determine the typical case, multiply the result of step 3by 3, and then add 1/2 the application scan time. 5 To determine the worst case, multiply the result of step 4 by 4.5, and then add 1 application scan time. Safety Considerations Guide for Triconex General Purpose v2 Systems
Page 1 and 2: Triconex General Purpose v2 Systems
Page 3 and 4: Contents Preface vii Summary of Sec
Page 5 and 6: Contents v Partitioned Processes. .
Page 7 and 8: Preface This guide provides informa
Page 9 and 10: Preface ix • All other requests a
Page 11 and 12: 1 Safety Concepts Overview 2 Hazard
Page 13 and 14: Overview 3 Protection Layers Method
Page 15 and 16: Hazard and Risk Analysis 5 Hazard a
Page 17 and 18: Hazard and Risk Analysis 7 Sample S
Page 19 and 20: Hazard and Risk Analysis 9 Safety L
Page 21 and 22: Hazard and Risk Analysis 11 • Eac
Page 23 and 24: Safety Standards 13 CAN/CSA-C22.2 N
Page 25 and 26: 2 Application Guidelines Overview 1
Page 27 and 28: General Guidelines 17 General Guide
Page 29 and 30: Guidelines for Triconex Controllers
Page 41 and 42: 3 Fault Management Overview 32 Syst
Page 43 and 44: System Diagnostics 33 System Diagno
Page 45 and 46: Operating Modes 35 Operating Modes
Page 47: Module Diagnostics 37 Analog Output
Page 51 and 52: Module Diagnostics 41 External Comm
Page 53 and 54: 4 Application Development Developme
Page 55 and 56: Development Guidelines 45 Array Ind
Page 57 and 58: Setting Scan Time 47 application. T
Page 59 and 60: Sample Safety-Shutdown Programs 49
Page 69 and 70: Alarm Usage 59 Alarm Usage To imple
Page 71 and 72: A Triconex Peer-to-Peer Communicati
Page 73 and 74: Data Transfer Time 63 Data Transfer
Page 75 and 76: Data Transfer Time 65 A typical dat
Page 77 and 78: Examples of Peer-to-Peer Applicatio
Page 79 and 80: B HART Communication Overview 70 HA
Page 81 and 82: HART Position Paper from TÜV Rhein
Page 89 and 90: C Safety-Critical Function Blocks O
Page 91 and 92: SYS_CRITICAL_IO 81 SYS_CRITICAL_IO
Page 93 and 94: SYS_CRITICAL_IO 83 Library Trident
Page 95 and 96: SYS_CRITICAL_IO 85 END_IF ; PREVIOU
Page 97 and 98: SYS_SHUTDOWN 87 Output Parameters (
Page 99 and 100:
SYS_SHUTDOWN 89 * the safety system
Page 101 and 102:
SYS_SHUTDOWN 91 ALARM_DISABLED_POIN
Page 103 and 104:
SYS_VOTE_MODE 93 Example For shutdo
Page 105 and 106:
Index A abbreviations, list of viii
Page 107 and 108:
Index 97 N NFPA 85 12 O operating m
Page 110:
Invensys Operations Management 5601
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