Instrumented Function Records

Instrumented Function records store details about a specific function of a safety instrumented system. This topic provides an alphabetical list and description of the fields that exist for the Instrumented Function family. The information in this table reflects the baseline state and behavior of these fields. This list is not comprehensive.

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Field	Data Type	Description	Behavior and Usage
Abnormal State	Character	A short description of the specific abnormal state of the operation.	This field does not appear on the datasheet.
Availability Target	Number	The percentage of time that the instrumented function must be operational.	Provide a value between 0 and 100. This value is compared with the availability of a Protective Instrument Loop to determine if the loop meets the availability target.
Concurrent Safe State Hazard	Text	A description of the hazardous event that could occur if the safe state associated with the instrumented function occurs simultaneously with the safe state of a different instrumented function.	This field appears on the Concurrent Safe State Hazard datasheet without a field caption, and a value is set by default. You can remove this value and enter your own value.
Concurrent Safe State Hazard?	Logical	Indicates whether the safe state associated with the instrumented function can cause a hazardous event if it occurs concurrently with the safe state of a different instrumented function.	This field appears on the Concurrent Safe State Hazard datasheet, which you can select to indicate that the safe state for the instrumented function can lead to a hazardous event if that safe state occurs simultaneously with the safe state of a different instrumented function.
Consequence Description	Text	A description of the risk that is associated with the hazardous event that exists in the Hazardous Event field.	If the value in the SIL Assessment Method field is PHA - Internal, after you select a Risk Assessment record from a Hazards Analysis, this field is populated with the value in the Consequence Description field in the Hazards Analysis Consequence record that is linked to the Risk Assessment record you selected.
Demand Rate (Source)	Character	The demand rate for the instrumented function (i.e., Low demand or High demand).	This field appears on the Safety Requirement Specification datasheet, and contains the text Low Demand by default. You can modify this value.
Equipment ID	Character	The ID of the Equipment that you want to link to the Instrumented Function.	On the datasheet, this field contains a button, which you can select to search for the Equipment. After you select an Equipment, a link is created between the selected Equipment and this Instrumented Function.
Equipment Key	Number	The Entity Key of the Equipment that is linked to this Instrumented Function.	The GE Digital APM system uses this value to populate the Equipment ID field that appears on the Instrumented Function datasheet.
Failure Rate UOM	Character	The unit of measure that is associated with the value in the Required Probability of Failure field.	This field contains the following values: PFD Avg. PFH When the value in the SIL Mode field is High Demand or Continuous, this field is disabled and populated with PFH. When the value in the SIL Mode field is Low Demand, this field is disabled and populated with PFD Avg.
Frequency of Initiating Event (Per yr)	Number	The number of times per year that the initiating event occurs.	If the value in the SIL Assessment Method field is PHA - Internal, after you select a Risk Assessment record from a Hazards Analysis, this field is populated with the value in the Cause Frequency (per year) field in the Hazards Analysis Cause record that is linked to the Hazards Analysis Consequence record that is linked to the Risk Assessment record you selected.
Function Type	Character	The type of the instrumented function.	This field contains a list with the following baseline values: Safety Protective
Functional Location ID	Character	The ID of the Functional Location that is linked to the Instrumented Function.	On the datasheet, this field a button, which you can select to search for the Functional Location.
Functional Location Key	Number	The Entity Key of the Functional Location that is linked to this Instrumented Function.	The GE Digital APM system uses this value to populate the Functional Location ID field.
Hazardous Event	Character	A description of the event for which the instrumented function exists to prevent or mitigate risk.	If the value in the SIL Assessment Method field is PHA - Internal, after you select a Risk Assessment record from a Hazards Analysis, this field is populated with the value in the Consequence Type field in the Hazards Analysis Consequence record that is linked to the Risk Assessment record you selected.
Hazards Analysis Date	Date	The date the Hazards Analysis to which this Instrumented Function is linked was last modified.	On the datasheet, this field is disabled and populated automatically with the value stored in the Last Modified Date field in the Hazards Analysis that is linked to this Instrumented Function and whose ID appears in the Hazards Analysis Reference field.
Hazards Analysis Reference	Character	The ID of the Hazards Analysis that is linked to this Instrumented Function.	This field does not appear on the datasheet.
Hazards Analysis Reference Key	Number	The Entity Key for the Hazards Analysis that is linked to this Instrumented Function.	This field is used by the GE Digital APM system to populate this Instrumented Function record with information from the Hazards Analysis that is linked to this Instrumented Function.
Initiating Event	Character	A short description of the initiating event whose description exists in the Initiating Event Description field.	If the value in the SIL Assessment Method field is PHA - Internal, after you select a Risk Assessment record from a Hazards Analysis, this field is populated automatically with the value in the Cause Type field in the Hazards Analysis Cause record that is linked to the Hazards Analysis Consequence record that is linked to the Risk Assessment record you selected.
Initiating Event Description	Text	A description of the event which could initiate a series of events that present the risk whose description exists in the Consequence Description field.	If the value in the SIL Assessment Method field is PHA - Internal, after you select a Risk Assessment record from a Hazards Analysis, this field is populated automatically with the value in the Cause Description field in the Hazards Analysis Cause record that is linked to the Hazards Analysis Consequence record that is linked to the Risk Assessment record you selected.
I/O Functional Relationship Details	Text	A description of the relationship between the inputs and outputs for the process, including details such as logic and mathematical functions.	This field appears on the Safety Requirement Specification datasheet.
Last Modified By	Character	The name of the user who last modified the record.	On the datasheet, this field is disabled and updated automatically whenever the record is modified.
Last Modified Date	Date	The date on which the record was last modified.	On the datasheet, this field is disabled and populated automatically.
Maintenance and Test Requirements	Text	A description of the requirements for maintenance and testing procedures for the instrumented function.	This field appears on the Safety Requirement Specification datasheet, and a value is set by default. You can remove this value and enter your own values.
Maintenance Override	Logical	A logical field that stores the value True or False and indicates whether the process requires override procedures for maintenance activities.	By default, this field does not appear on the datasheet.
Manual Shutdown	Logical	A logical field that stores the value True or False and indicates whether the process requires manual shutdown.	By default, this field does not appear on the datasheet.
Max Process Variable	Number	A number representing the upper value for the process variable range.	This field appears on the Safety Requirement Specification datasheet. This value combined with the value stored in the Min Process Variable field make up the process variable range.
Min Process Variable	Number	A number representing the lower value for the process variable range.	This field appears on the Safety Requirement Specification datasheet. This value combined with the value stored in the Max Process Variable field make up the process variable range.
Normal Operation Mode	Text	A description of the normal operating mode for the instrumented function.	By default, this field appears on the Safety Requirement Specification datasheet and a value is set. You can remove this text and enter your own values.
Operation Mode Description	Character	The description of the abnormal mode of operation.	This field appears on the Safety Requirement Specification datasheet and is enabled only if the value for the Operation Modes field is ABNORMAL. If the value in the Operation Modes field is NORMAL, this field is disabled.
Operation Modes	Character	The mode of operation for the instrumented function.	This field appears on the Safety Requirement Specification datasheet and contains the following values: Normal : By default, this is the value that is selected. Abnormal : If you select this value, the following fields are enabled: Abnormal States Operation Mode Description
Operator Interface Requirement	Text	A description of the Operator Interface requirements.	This field appears on the Safety Requirement Specification datasheet, and a value is set by default. You can remove this text and enter your own values.
PIF Description	Character	Stores a description of the instrumented function.	On the datasheet, this field appears as a text box labeled IF Description, in which you can enter your own value.
PIF ID	Character	An ID for the instrumented function.	On the datasheet, this field appears as a text box labeled IF ID, in which you can enter your own value. This value will appear in the list of Instrumented Functions on the left pane on the SIL Analysis Summary page. This field is required.
Pre Alarm	Number	A number representing the point on the process variable range at which the pre-alarm should be triggered.	This field appears on the Safety Requirement Specification datasheet.
Process Service Description	Text	A description of the specifications for the process service.	This field appears on the Safety Requirement Specification datasheet.
Process Speed	Number	A number representing the time in seconds that the process for which the instrumented function takes to complete.	None
Required Probability of Failure	Number	A number that represents the target probability that an instrumented function failure will occur.	If the value in the SIL Assessment Method field is Risk Matrix - Internal, this field is disabled and populated automatically based on the SIL requirements from the Risk Matrix. If the value in the SIL Assessment field is Layer of Protection Analysis Internal, this field is disabled and populated automatically with the difference between the values in the Mitigated Consequence Frequency field and the Required Mitigated Consequence Frequency field on the LOPA datasheet. For all other SIL Assessment methods, you can type a value manually in the Required Probability of Failure field. Note that: The value that you type must fall within a certain range, which is determined by the value in the Selected SIL Level field. If you modify the value in the Selected SIL Level field, the value in this field will be updated automatically to fall within the correct range of values for that level. If you try to type a value into the Required Probability of Failure field without first selecting a value from the Selected SIL Level list or you type a value that is outside of the acceptable range, an error message will appear. If the value in the SIL Mode field is Low Demand, when you type a value in the Required Probability of Failure field, the value in the Risk Reduction Factor field will be populated automatically with the inverse of the value you type. Likewise, if you type a value in the Risk Reduction Factor box, the value in the Required Probability of Failure field will be populated automatically with the inverse of the value that you type. After you type a value in the Required Probability of Failure field, it is converted automatically to scientific notation form (e.g., 1E-07).
Required SIF Action	Text	A description of the action that the instrumented function performs in response to a triggered alarm.	This field appears on the Safety Requirement Specification datasheet.
Reset Requirement	Text	A description of the requirements for resetting a process after it has been tripped.	This field appears on the Safety Requirement Specification datasheet and a value is set by default. You can remove this text and enter your own value.
Response Time	Number	A numeric value that represents the time in seconds that it takes for the instrumented function to respond to the initiating event and bring the process to a safe state.	None
Risk Reduction Factor (RRF)	Number	A number representing the factor by which the risk should be reduced for the instrumented function.	If the value in the SIL Mode field is Low Demand and the value in the SIL Assessment Method field is Layer of Protection Analysis - Internal or Risk Matrix - Internal, this field is disabled and populated automatically with the inverse of the value in the Required Probability of Failure field. For all the other SIL Assessment methods, when the value in the SIL Mode field is Low Demand and the value in the SIL Assessment Method field is not Layer of Protection Analysis - Internal or Risk Matrix - Internal, this field is enabled and you can type a value directly into the Risk Reduction Factor field. Note that: The value that you type must fall within a certain range, which is determined by the value in the Selected SIL Level field. If you modify the value in the Selected SIL Level field, the value in this field will be updated automatically to fall within the correct range of values for that level. If you try to type a value in the Risk Reduction Factor field without first selecting a value from the Selected SIL Level list or you type a value that is outside of the acceptable range, an error message will appear. If you type a value in the Risk Reduction Factor field, the value in the Required Probability of Failure field will be populated automatically with the inverse of the value that you type. Likewise, if you type a value into the Required Probability of Failure field, the value in the Risk Reduction Factor field will be populated automatically with the inverse of the value that you type. If the value in the SIL Mode field is High Demand or Continuous, this field is disabled and does not contain a value.
Safe State Description	Text	A description of the safe state to which the process should be taken via the instrumented function.	None
Selected SIL Level	Number	A number representing the SIL value that is required for the instrumented function.	On the datasheet, this field is disabled and populated automatically if the value in the SIL Assessment Method field is anything other than External. If the SIL Assessment Method field contains an External value, this field is enabled and appears as a list that is populated with values from the MI SAFETY INDEX LEVEL System Code Table. You can select a value from the list. If a value exists in the Required Probability of Failure field and you try to delete the value in the Selected SIL Level field, an error message appears, and you will not be able to delete the value.
SIL Analysis Key	Number	The Entity Key of the SIL Analysis to which the Instrumented Function is linked.	This field is used internally by the GE Digital APM system.
SIL Assessment Method	Character	The method used to assess the risk that is associated with the instrumented function.	This field contains the following values: Risk Matrix - Internal Layer of Protection Analysis Internal PHA Internal External These values are defined in the MI_SIL_ASSESSMENT_METHOD system code table. If you select the PHA - Internal option, there must be a value in the Hazards Analysis Reference field. Otherwise, an error message will appear.
SIL Mode	Character	The SIL mode that is defined for this instrumented function.	This field contains the following baseline values: Low Demand High Demand Continuous
SIS System ID	Character	The ID of the Logic Solver to which the Instrumented Function is linked.	On the datasheet, this field appears as a list labeled SIS ID and contains the values that exist in the SIS ID field in the Logic Solvers that are linked to the SIL Analysis with which you are currently working. If a logic solver has been set as default, then the ID of the same logic solver is populated in the SIS System ID field.
Site Description	Character	A description of the site that is specified in the Site ID field.	None
Site ID	Character	The ID of the site that is associated with the instrumented function.	On the datasheet, this field is disabled and populated automatically with the value in the Site ID field of the associated SIL Analysis.
Spurious Trip Limit (per yr)	Number	A number representing the number of times per year it is acceptable for a spurious trip to occur for this instrumented function.	This value is used to determine the value in the Meets STR Limit field in a Protective Instrument Loop that is linked to the Instrumented Function.
Startup And Restart Procedure	Text	A detailed description of the start up and restart procedures for the process.	This field appears on the Safety Requirement Specification datasheet and a value is set by default. You can remove this text and enter your own value.
Survival Requirement	Text	A description of the requirements for the instrumented function to survive a catastrophic event, such as an earthquake.	This field appears on the Safety Requirement Specification datasheet and a value is set by default. You can remove this text and enter your own value.
Trip Mode	Character	A short description of the trip mode (i.e., energize to trip or de-energize to trip).	This field appears on the Safety Requirement Specification datasheet and the value is set to de-energize to trip by default. You can remove this value and enter your own value.
Trip Point	Number	A number representing the point on the process variable range at which the trip alarm should be triggered.	This field appears on the Safety Requirement Specification datasheet.
Unit Description	Character	A description of the unit that is specified in the Unit ID field.	None
Unit ID	Character	The ID for the unit where the instrumented function exists.	You can enter your own value.
UOM	Character	Units of measure for values such as Trip Point, Min Process Variable, Max Process Variable, Pre-alarm.	None