RRM 3-14 dbCommon

EPICS Record Reference Manual

Fields Common to All Record Types

Introduction

This chapter contains a description of fields that are common to all records. These fields are defined in dbcommon.dbd.

Scan Fields

These fields contain information related to how and when a record processes. For a further explanation of these record processing and these fields, see Scanning Specification, Chapter 1, 1. A few records have unique fields that also affect how they process. These fields, if any, will be listed and explained in the chapter for each record.

Field Summary

Field	Type	DCT	Initial	Access	Modify	Rec Proc Monitor	PP
SCAN	GBLCHOICE	Yes	Passive	Yes	Yes	No	No
PINI	GBLCHOICE	Yes	No	Yes	Yes	No	No
PHAS	SHORT	Yes	0	Yes	Yes	No	No
EVNT	SHORT	Yes	0	Yes	Yes	No	No
PRIO	GBLCHOICE	Yes	Low	Yes	Yes	No	No
DISV	SHORT	Yes	1	Yes	Yes	No	No
DISA	SHORT	No	0	Yes	Yes	No	No
SDIS	INLINK	Yes	0	Yes	Yes	No	No
PROC	UCHAR	No	0	Yes	Yes	No	Yes
DISS	GBLCHOICE	Yes	No Alarm	Yes	Yes	No	No
LCNT	UCHAR	No	0	Yes	No	No
PACT	UCHAR	No	0	Yes	No	No
FLNK	FWDLINK	Yes	Null	Yes	Yes	No	No
SPVT	NOACCESS	No	4	No	No	No

Field Description

Name	Summary	Description
SCAN	Scanning Rate	This can be one of the periodic intervals (.1 second, .2 second, .5 second, 1 second, 2 second, 5 second, 10 second, I/O Intr, Event, or Passive.
PINI	Process at Initialization	If this field is set to YES during database configuration, then the record is processed once at IOC initialization (before the normal scan tasks are started).
PHAS	Scan Phase Number	This field orders the records within a specific SCAN group. This is not meaningful for passive records. All records of a specified phase are processed before those with higher phase number. Whenever possible it is better to use linked passive records to enforce the order of processing rather than phase number.
EVNT	Event Number	Event number for scan type SCAN_EVENT. All records with scan type event and the same EVNT value will be processed when a call to post_event for EVNT is made. The call to post_event is: post_event(short event_number)
PRIO	Priority	Scheduling priority for processing I/O Event scanned records and asynchronous record completion tasks.
DISV	Disable Value	If DISV=DISA, then the record will be disabled, i.e. dbProcess will not process the record.
DISA	Scan Disable Input Link Value	This is the value that is compared with DISV to determine if the record is disabled. Its value is obtained via SDIS if SDIS is a database or channel access link. If SDIS is not a database or channel access link, then DISA can be set via dbPutField or dbPutLink.
SDIS	Scan Disable Input Link	An input link from which to obtain a value for DISA. This field is ignored unless it is a database link or a channel access link. If it is a database or a channel access link, dbProcess calls dbGetLink to obtain a value for DISA before deciding to call the processing routine.
PROC	Process Record	A record will be processed whenever a dbPutField is directed to this field.
DISS	Disable Alarm Severity	When this record is disabled, it will be put into alarm with this severity and a status of DISABLE_ALARM.
LSET	Lock Set	The lock set to which this record belongs. All records linked in any way via input, output, or forward database links belong to the same lock set. Lock sets are determined at IOC initialization time, and are updated whenever a database link is added, removed or altered.
LCNT	Lock Count	The number of times in succession dbProcess finds the record active, i.e. PACT is TRUE. If dbProcess finds the record active MAX_LOCK (currently set to 10) times in succession, it raises a SCAN_ALARM.
PACT	Processing Active	See Application Developers Guide for details on usage. PACT is TRUE while the record is being processed. For asynchronous records PACT can be TRUE from the time record processing is started until the asynchronous completion occurs. As long as PACT is TRUE, dbProcess will not call the record processing routine.
FLNK	Forward Link	This field is a database link. If FLNK is specified, processing this record will force a processing of the scan passive forward link record.
SPVT	Scan Private	This field is for private use of the scanning system.

Alarm Fields

These fields indicate the status and severity of alarms, or else determine the how and when alarms are triggered. For a further explanation of database alarms, see Alarm Specification, Chapter 1, 4. Of course, many records have alarm-related fields not common to all records. These fields are listed and explained in the appropriate chapter on each record.

Field Summary

Field	Type	DCT	Initial	Access	Modify	Rec Proc Monitor	PP
STAT	GBLCHOICE	No	UDF_ALARM	Yes	No	Yes
SEVR	GBLCHOICE	No	INVALID_ALARM	Yes	No	Yes
NSTA	GBLCHOICE	No	No Alarm	Yes	No	No
NSEV	GBLCHOICE	No	No Alarm	Yes	No	No
ACKS	GBLCHOICE	No	No Alarm	Yes	No
ACKT	GBLCHOICE	No	Yes	Yes	No
UDF	UCHAR	No	1	Yes	Yes	No	Yes

Field Description

Name	Summary	Description
STAT	Current Alarm Status	These four fields are the alarm status and severity fields. STAT and SEVR are the values seen outside database access. NSTA and NSEV are the fields the database access, record support, and device support use to set new alarm status and severity values. Whenever any software component discovers an alarm condition, it uses the following macro function: recGblSetSevr(precord,new_status,new_severity) This ensures that the current alarm severity is set equal to the highest outstanding alarm. The file alarm.h defines all allowed alarm status and severity values.
SEVR	Current Alarm Severity
NSTA	New Alarm Status
NSEV	New Alarm Severity
ACKS	Alarm Acknowledge Severity	Highest severity unacknowledged alarm
ACKT	Alarm Acknowledge Transient	Is it necessary to acknowledge transient alarms?
UDF	VAL Undefined	This indicates that the record has never been processed or its value is UnDeFined. Typically this is caused by a failure in device support, a record that has never been processed, or where the VAL field currently contains a NaN (not a number). UDF is initialized to TRUE at IOC initialization. Record and device support routines which write to the VAL field are responsible for setting UDF.

Device Fields

These fields contain information about the device and record support used by a record.

Field Summary

Field	Type	DCT	Initial	Access	Modify	Rec Proc Monitor	PP
RSET	NOACCESS	No	4	No	No	No
DSET	NOACCESS	No	4	No	No	No
DPVT	NOACCESS	No	4	No	No	No

Field Description

Name	Summary	Description
RSET	Address of Record Support Entry Table	See Application Developers Guide for details on usage.
DSET	Address of Device Support Entry Table	This address of the device support entry table for this record. The value of this field is determined at IOC initialization time. Record support routines use this field to locate their device support routines.
DPVT	Device Private	This field is for private use of the device support modules.

Debugging Fields

These fields can aid in the debugging process.

Field Summary

Field	Type	DCT	Initial	Access	Modify	Rec Proc Monitor	PP
TPRO	UCHAR	No	0	Yes	Yes	No	No
BKPT	NOACCESS	No	0	No	No	No

Field Description

Name	Summary	Description
TPRO	Trace Processing	If this field is non-zero a message is printed whenever this record is processed, and when any other record in the same lock-set is processed by a database link from this record.
BKPT	BreakPoint	Indicates if there is a breakpoint set at this record. This supports setting a debug breakpoint in the record processing. STEP through database processing can be supported using this.

Miscellaneous Fields

These are miscellaneous fields common to all record types.

Field Summary

Field	Type	DCT	Initial	Access	Modify	Rec Proc Monitor	PP
NAME	STRING [61]	Yes	0	Yes	No	No
DESC	STRING [41]	Yes	Null	Yes	Yes	No	No
ASG	STRING [29]	Yes	Null	Yes	Yes	No
TSE	SHORT	Yes	0	Yes	Yes	No
TSEL	INLINK	Yes	Null	Yes	Yes	?	No
DTYP	DEVCHOICE	Yes	Soft Record Support	Yes	No	No
MLOK	NOACCESS	No	0	No	No	No
MLIS	NOACCESS	No	0	No	No	No
DISP	UCHAR	No	0	Yes	Yes	Yes	No
PUTF	UCHAR	No	0	Yes	No	No
RPRO	UCHAR	No	0	Yes	No	No
ASP	NOACCESS	No	4	No	No	No
PPN	NOACCESS	No	4	No	No	No
PPNR	NOACCESS	No	4	No	No	No
RDES	NO_ACCESS
TIME	NOACCESS	No	8	Option	No	No	No

Field Description

Name	Summary	Description
NAME	Record Name	A 60 character record name supplied by the application developer. This name is the means of identifying a specific record. It must have a unique value across all IOCs attached to the same local area subnet, and should use only this limited set of characters: a-z A-Z 0-9 _ - : [ ] < > ;
DESC	Description	An arbitrary 40 character record description supplied by the application developer.
ASG	Access Security Group	A character string value defining the access security group for this record. If left NULL, the record is placed in group DEFAULT.
TSEL	Time Stamp Event Link	An input link for obtaining the time stamp. If this link references the .TIME field of a record then the time stamp of the referenced record becomes the time stamp for this record as well. In this case, an internal flag is set and ".TIME" is then overwritten by ".VAL". If any other field is referenced, the field value is read and stored in the .TSE field which is then used to acquire a timestamp.
TSE	Time Stamp Event	This indicates the mechanism to use to get the time stamp. '0' - call get time as before '-1' - call the time stamp driver and use the best source available. '-2' - the device support provides the time stamp from the hardware. Values between 1-255 request the time of the last occurance of a generalTime event.
DTYP	Device Type	This field specifies the device type for the record. Each record type has its own set of device support routines which are specified in devSup.ASCII. If a record type does not have any associated device support, DTYP and DSET are meaningless.
MLOK	Monitor Lock	The lock used by the monitor routines when the monitor list is being used. The list is locked whenever monitors are being scheduled, invoked, or when monitors are being added to or removed from the list. This field is accessed only by the dbEvent routines.
MLIS	Monitor List	This is the head of the list of monitors connected to this record. Each record support module is responsible for triggering monitors for any fields that change as a result of record processing. Monitors are present if mlis count is greater than zero. The call to trigger monitors is: db_post_event(precord,&data,mask), where "mask" is some combination of DBE_ALARM, DBE_VALUE, and DBE_LOG.
DISP	Disable putFields	If this field is set to TRUE, then all dbPutFields (normally issued by channel access) directed to this record are ignored except to the field DISP itself.
PUTF	dbPutField Process	Did dbPutField cause the current record processing?
RPRO	Reprocess	Reprocess record when current processing completes.
ASP	Access Security Private
PPN	Address of putNotify	Address of putNotify callback.
PPNR	Next Record for putNotify	Next record for PutNotify.
RDES	Address of dbRecordType
TIME	Time	The time when this record was last processed, in standard format.

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EPICS Record Reference Manual