RRM 3-13 Event

EPICS Record Reference Manual

Event

The normal use for this record type is to post an event and/or process a forward link. Device support for this record can provide a hardware interrupt handler routine for I/O Event-scanned records.

Parameter Fields

The records in this field fall into the following groups of parameters:

• scan parameters
• read parameters
• event number parameters
• simulation mode parameters

Scan Parameters

The event record has the standard fields for specifying under what circumstances it will be processed. If the SCAN field specifies I/O Intr, then device support will provide an interrupt handler, posting an event number when an I/O interrupt occurs. These fields are listed in Scan Fields. In addition, Scanning Specification explains how the scanning fields work. Note that I/O event scanning is only supported for those card types that interrupt.

Input Specification

The device support routines use the address in this record to obtain input. For records that provide an interrupt handler, the INP field should specify the address of the I/O card, and the DTYP field should specify a valid device support module. Be aware that the address format differs according to the card type used. See Address Specification for information on the format of hardware addresses and specifying links. You can see a list of the device support modules currently supported at the user's local site by using the dbst utility in R3.13.

For soft records, the INP field can be a constant, a database link, or a channel access link. For soft records, the DTYP field should specify Soft Channel.

Field	Summary	Type	DCT	Initial	Access	Modify	Rec Proc Monitor	PP
INP	Input Link	INLINK	Yes	0	No	No	N/A	No
DTYP	Device Type	DEVCHOICE	Yes	0	Yes	No	No

Event Number Parameters

The VAL field contains the event number read by the device support routines. It is this number which is posted. For records that use Soft Channel device support, it can be configured before run-time or set via dbPuts.

Field	Summary	Type	DCT	Initial	Access	Modify	Rec Proc Monitor	PP
VAL	Event Number to Post	USHORT	Yes	0	Yes	Yes	Yes	No

Operator Display Parameters

See Fields Common to All Record Types for more on the record name (NAME) and description (DESC) fields.

Field	Summary	Type	DCT	Initial	Access	Modify	Rec Proc Monitor	PP
NAME	Record Name	STRING [29]	Yes	0	Yes	No	No
DESC	Description	STRING [29]	Yes	Null	Yes	Yes	No	No

Alarm Parameters

The Event record has the alarm parameters common to all record types. Alarm Fields lists other fields related to a alarms that are common to all record types.

Simulation Mode Parameters

The following fields are used to operate the event record in the simulation mode. See Fields Common to Many Record Types for more information on these fields.

Field	Summary	Type	DCT	Initial	Access	Modify	Rec Proc Monitor	PP
SIOL	Simulation Value Location	INLINK	Yes	0	No	No	N/A	No
SVAL	Simulation Value	DOUBLE	No	0	Yes	Yes	No	No
SIML	Simulation Mode Location	INLINK	Yes	0	No	No	N/A	No
SIMM	Simulation Mode	GBLCHOICE	No	0	Yes	Yes	No	No
SIMS	Simulation Mode Alarm Severity	GBLCHOICE	Yes	0	Yes	Yes	No	No

Record Support

Record Support Routines

init_record

This routine initializes SIMM with the value of SIML if SIML type is a CONSTANT link or creates a channel access link if SIML type is PV_LINK. SVAL is likewise initialized if SIOL is CONSTANT or PV_LINK.

If device support includes init_record, it is called.

process

See next section.

get_value

Fills in the values of struct valueDes so that they refer to VAL.

Record Processing

Routine process implements the following algorithm:

1. readValue is called. See Input Records for more information.
2. If PACT has been changed to TRUE, the device support read routine has started but has not completed reading a new input value. In this case, the processing routine merely returns, leaving PACT TRUE.
3. If VAL > 0, post event number VAL.
4. Check to see if monitors should be invoked. Alarm monitors are invoked if the alarm status or severity has changed NSEV and NSTA are reset to 0.
5. Scan forward link if necessary, set PACT FALSE, and return.

Device Support

Fields of Interest To Device Support

Each record must have an associated set of device support routines. The device support routines are primarily interested in the following fields:

Name	Summary	Description
PACT	Processing Active	See Fields Common to All Record Types for an explanation of these fields.
DPVT	Device Private
UDF	VAL Undefined
NSEV	New Alarm Severity
NSTA	New Alarm Status
INP	Input Link	This field is used by the device support routines to locate its input.
PRIO	Priority	This value must be used by the device support interrupt handler to set the scheduling priority for processing this record.

Device Support Routines

Device support consists of the following routines:

report

report(FILE fp, interest)

Not currently used.

init

init()

This routine is called once during IOC initialization.

init_record

init_record(precord)

This routine is optional. If provided, it is called by the record support init_record routine.

get_ioint_info

get_ioint_info(int cmd,struct dbCommon *precord,IOSCANPVT *ppvt)

This routine is called by the ioEventScan system each time the record is added or deleted from an I/O event scan list. cmd has the value (0,1) if the record is being (added to, deleted from) an I/O event list. It must be provided for any device type that can use the ioEvent scanner.

read_event

read_event(precord)

This routine returns the following values:

• 0: Success.
• Other: Error.

Device Support For Soft Records

The Soft Channel device support module is available. The INP link type must be either CONSTANT, DB_LINK, or CA_LINK.

If the INP link type is CONSTANT, then the constant value is stored into VAL by init_record, and UDF is set to FALSE. If the INP link type is PV_LINK, then dbCaAddInlink is called by init_record.

read_event calls recGblGetLinkValue to read the current value of VAL. See Input Records for details on soft input.

---

EPICS Record Reference Manual - 19 MAY 1998